#⚛️┃physics | Official Unity Discord | Page 44

meager ledge Jan 10, 2020, 3:35 PM

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Like my forklift isn't one solid gameobject, the animations are create in unity. There is no rig for the forklift

pseudo laurel Jan 10, 2020, 4:38 PM

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hi guys, i'm new here. I'm trying to learn unity so i started to create a platform controller to understand movements etc. i started by taking the character controller of Lost Cypt (the new demo that use the new features of unity) and I started to tweak it. Unfortunately i can't find a way to fix the physic of my character. I used sprite shape to create the world but if the player stands on a slope it start to slide down and it keeps moving for a while. I created a physic 2d material with friction 0 bounce 0 and i applied it to both the player collider and spriteshape collider but it didn't help. Anyone can point me to the right direction if you faced already the same issue?

sly violet Jan 10, 2020, 6:18 PM

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I am using wheel colliders that make my forklift move
But i am guessing that all the parts are separate objects, might interfere with the physics
Hmm. That really should be fine in itself; the wheels normally move the whole based on joints, which work entirely within the physics engine. Something else going on.

strong leaf Jan 11, 2020, 7:57 AM

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I just implemented a constant distance jump, while the x velocity is increasing

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The problem is, giving a lower y velocity will result in a lower max height too

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Is there any workaround to keep constant distance and height while increasing the x velocity?

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I'm really curious how endless runners achieve this

peak panther Jan 11, 2020, 2:13 PM

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Anyone have experience writing a 2D Kinematic Character Controller?

charred vault Jan 11, 2020, 2:22 PM

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What's your question Igotlazy?

peak panther Jan 11, 2020, 2:29 PM

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@charred vault How exactly would you code a pushing behaviour? When an object calculates it's move would it preform a GetComponent on hit colliders and see if they're pushable? Wouldn't so many GetComponents be taxing?

charred vault Jan 11, 2020, 2:36 PM

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well you collide then you would check if its 'pushable' but that wouldn't necessarily have to be done with GetComponents

peak panther Jan 11, 2020, 2:37 PM

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Also what method of collision detection should I even use? I've seen a lot of raycasts based ones be pretty inaccurate. A tutorial that Unity put out uses Rigidbody2D.Cast. Should I use that?

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What other methods are there for detecting if its pushable, other than a tag or something?

sturdy ibex Jan 11, 2020, 2:58 PM

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Id say void OnCollisionEnter or OnCollisionStay generally gets the job done

peak panther Jan 11, 2020, 3:05 PM

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This is for a Kinematic controller though

sturdy ibex Jan 11, 2020, 3:05 PM

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Oh ok

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Does it have colliders?

peak panther Jan 11, 2020, 3:12 PM

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Kinematic Rigidbodies are not under the influence of forces or collisions by default.

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Doesn't matter if it has a collider, it won't collide by nature.

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The point of them is to define your own movement code.

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While still being able to interact with most other things in the physics simulation (like triggers).

sturdy ibex Jan 11, 2020, 3:13 PM

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Oh ok

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Maybe boxraycasting or just regular old raycasting would do it

ocean horizon Jan 11, 2020, 3:26 PM

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@peak panther One method is to use a Layer to indicate a pushable. That way you can include that layer in the filter when you perform physics either exclusively that layer so all results are only "Pushables" or as part of many layers. Then you only have to check the layers on the results which is very quick.

twilit fable Jan 11, 2020, 5:48 PM

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Does the triangleIndex of a RayCast hit always refer to the MeshCollider's mesh? Can't that be different to the actual mesh of the object?

jovial creek Jan 11, 2020, 5:49 PM

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I'm using a raycast to allow my character to interact with the world (pickup objects/drop them etc.) on one scene everything works perfectly but when I do it on another scene the raycast doesn't hit the object it picks up (I debugged with a draw ray it looks like it should be hitting the object) I've also put a "focusedobject" in the inspector to get info on what it's looking at and it doesn't show the object once it's picked up, any ideas?

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it's the exact same scripts and prefabs in between the scenes

sly violet Jan 11, 2020, 6:32 PM

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@strong leaf

Is there any workaround to keep constant distance and height while increasing the x velocity?
Yup - increase gravity. It might look dumb, though.
I'm really curious how endless runners achieve this
Every Endless Runner I've ever played - and I've played a lot - simply let you jump further as you go faster.

vivid arch Jan 11, 2020, 6:32 PM

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RaycastHit hit = new RaycastHit(); RaycastHit[] wheelHits = Physics.RaycastAll(tr.position, -upDir, hoverDistance, GlobalControl.wheelCastMaskStatic);
how do i make it detect collisions with something other than Default layer?

strong leaf Jan 11, 2020, 6:34 PM

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@sly violet thanks, i've found a workaround tho

glad heart Jan 11, 2020, 6:34 PM

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@vivid arch you can give a layer just after all of your parameters 😉 Just add , Layer.NameToLayer("Enemy")); for example 😉

strong leaf Jan 11, 2020, 6:35 PM

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@sly violet instead of using gravity while jumping, I've designed my own parabola and just teleporting the ball in different points based on timePassed since jumped

vivid arch Jan 11, 2020, 6:35 PM

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ima try it

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@glad heart Returns error

📎 unknown.png

glad heart Jan 11, 2020, 6:37 PM

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Did you created your layer previously ?

vivid arch Jan 11, 2020, 6:38 PM

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im using Randomation vehicle physics.

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but no, the script doesnt create any layers

glad heart Jan 11, 2020, 6:42 PM

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Just open your project with Unity, create an empty GameObject (or select an already existing GO) and under Layer select Add Layer then add the name of your layer (here it will be Map I suppose) . Now the Layer is created and known by Unity. After that, all you need to do is to set gameObject.layer of all the objects that are considered to be your Map and you'll be good to go 😉

vivid arch Jan 11, 2020, 6:42 PM

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removing this fixed it

📎 unknown.png

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i have many objects with map layer.

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the hover car thing didnt detect Map layer colliders so it just fell on the ground instead of hover.

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now it does hover

glad heart Jan 11, 2020, 6:43 PM

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Great !

strong leaf Jan 11, 2020, 8:52 PM

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I got a really strange movement behavior

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📎 unknown.png

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when I'm jumping while the character moves on x axis it will glitch out and teleport a small number of units on the z axis

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which doesnt really make sense, cuz I'm using the same position, the one I'm changing is the y position, trying to move it along a parabola, so I'm interpolating positions based on time since player pressed jumo

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jump*

peak panther Jan 11, 2020, 10:34 PM

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So I've got 2 colliders here. One is a box (blue) and the other (black) is a tilemap collider 2d that uses a composite collider so all the tiles fuse together. In a script I use Rigidbody2D.GetContacts and check if the normal of a contact is (0, -1), if so it makes the collider start to fall. For some reason I am getting this behaviour in this situation, where the collider is simply rubbing against the wall. This does not happen against every wall, and for some reason there IS a contact that is reporting a value of (0, -1). Why?
https://i.gyazo.com/015cf97d08cc0575de57530f3665d74a.mp4

▶ Play video

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📎 unknown.png

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Here is the code, called in FixedUpdate
Colstates is just a struct that contains 4 bools that represent whether it collided against a side.

Either Rigidbody2D.GetContacts isn't giving back the correct contacts or I'm doing something fundamentally wrong.
Is my collider sorta pushing into the tilemap collider, causing a bad reading?
If so how do I prevent it?

sly violet Jan 11, 2020, 11:56 PM

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Sure looks like you're hitting your head on the halfway point of that wall.

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Tilemap colliders are supposed to smooth those out.

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Maybe post the settings of your tilemap collider and composite collider.

peak panther Jan 11, 2020, 11:58 PM

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@sly violet Sure.

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📎 unknown.png

sly violet Jan 12, 2020, 12:00 AM

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Hey, here's something that might fix it right up for you: Go give a small Edge Radius to Box Collider 2d of the player. That makes it have rounded corners, making it impossible to hit the top on the edge of a corner.

strong leaf Jan 12, 2020, 12:13 AM

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@sly violet I just reverted my project, and managed to add a variable gravity and jump seed, with constant height and distance traveled. I wanted to thank you so much for all the help you're offering, you're doing a great job explaining! :))

sly violet Jan 12, 2020, 12:14 AM

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You're welcome, glad I could help!

peak panther Jan 12, 2020, 12:33 AM

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@sly violet I’ve done that and unfortunately it still happens occasionally.

golden eagle Jan 12, 2020, 3:15 AM

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i recall doing this a while ago but forgot: how can i make a game object ignore physics collisions with another object?

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i still want them to trigger collisions, but not collide with physics, like pushing each other

sly violet Jan 12, 2020, 3:32 AM

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You can set Colliders to Trigger, and they won't have physics interactions.

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Triggers still generate OnTrigger events.

golden eagle Jan 12, 2020, 3:39 AM

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oh cool thanks

gilded sparrow Jan 12, 2020, 6:22 AM

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But why?

📎 unknown.png

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I'm only using the CompositeCollider2D for Cinemachine purposes, so i won't need rigidbody. I guess i can set it kinematic. But still, why is it mandatory to have RB for CompositeCollider?

sly violet Jan 12, 2020, 7:33 AM

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Colliders have to be attached to the same rigidbody to use a composite. No rigidbody to group them with, no composite.
BTW, if you're moving a collider (or group of colliders) it's always more efficient to assign them to a rigidbody and move that.

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The physics system expects that static colliders (ones without a rigidbody) aren't going to move, and bakes in a bunch of stuff that has to be recalculated if you do. Same thing happens if you move colliders around within a rigidbody.

ocean horizon Jan 12, 2020, 10:14 AM

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@gilded sparrow What @sly violet says is spot on. Also, set the Rigidbody2D body-type to Static. This is identical to not adding a Rigidbody2D as the collider will get added to a static Rigidbody2D behind the scenes. It's not any overhead.

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This is actually the core problem I had when I created the CompositeCollider2D. The problem was that colliders that don't have a Rigidbody2D are added to the static ground-body that is created behind the scenes. This means all such colliders are attached to this body that never moves. If you were to tell such a collider to use a composite then there's a few problems. The first is that we have no place for you to define the CompositeCollider2D for this behind-the-scenes body (it's not even a Rigidbody2D but a physics body). The other problem, assuming we could define a composite, was that all colliders like this would go to the same composite making them more and more expensive as you added more of them. When shapes are created in the physics system, they are created and attached to a body otherwise they don't work.

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So the composite needs a body and it allows you to set that to static so you get identical behaviour and it allows you to control the scope of what gets blended with what. It also ensures that the colliders that are merged together are on the same rigidbody so they cannot move relative to each other which is how the physics wants to work as it moves bodies, not colliders. Moving colliders relative to the body is expensive. Moving bodies isn't because that's what the physics system is all about; moving bodies and updating transforms.

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Adding a Rigidbody2D and setting to Static isn't an overhead. Go ahead and create as many as you like. They're, for the most part, ignored by the physics system. It's colliders, contacts and joints and solving them that costs.

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Anyway, hope that info helps.

gilded sparrow Jan 12, 2020, 1:24 PM

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Super detailed! Cheers
I didn't expect the CinemachineConfiner would ask for a Composite now (maybe that's new)?
And i thought any child colliders under a parent RB used to be considered a Composite. Is the Composite now the way to explicitly declare that, and now child colliders has no connection with the parent RB otherwise?

ocean horizon Jan 12, 2020, 1:28 PM

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So I had to look-up CinemachineConfiner as I don't work with it. Yes, I can see it uses a 2D/3D collider as the bounding area. I can only assume though that all it really does is look at the AABB bounds and nothing else. It would operate on the base type of Collider2D presumably and wouldn't have to know about individual colliders if it's just AABB bounds. Probably uses: https://docs.unity3d.com/ScriptReference/Collider2D-bounds.html

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And i thought any child colliders under a parent RB used to be considered a Composite. Is the Composite now the way to explicitly declare that, and now child colliders has no connection with the parent RB otherwise?
Those are different things. The CompositeCollider2D is merging the geometry and acts as a single collider. That is different than having multiple individual colliders all attached to a single Rigidbody2D which is typically known as a Compound collider set-up.

gilded sparrow Jan 12, 2020, 2:24 PM

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Ah right. So basically child colliders without their "Used by Composite" checked, won't be optimized as a single collider. But as a rigidbody, it's still referring to the (closest) parent RB

ocean horizon Jan 12, 2020, 2:32 PM

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To be clear, the composite has nothing to do with compound colliders. At a more basic level, when you check "Used by Composite" on a Collider2D, it's as if the collider doesn't exist anymore. Only its geometry is used by the composite to build a single composite. If you look at the Inspector on any Collider you'll see "Info -> Shape Count". This is the number of primitive shapes the collider produces and it's these that are attached to the Rigidbody2D. When you use a composite, you'll notice that the Shape Count for that Collider goes to zero because it doesn't exist in the physics system anymore.

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The compound set-up you're referring to isn't a special feature, it's just that you can have multiple primitive shapes at different poses attached to the rigidbody.

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When you add any Collider2D into the hierarchy we simply create the collider primitive shapes at the appropriate position relative to the Rigidbody2D.

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Shapes live in Rigidbody2D space so you move the body and the shapes "move" with it.

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Again, nothing to do with a composite which is the act of looking at all the shapes on colliders with the composite option on, merging the geometry together which can produce different numbers of shapes covering the same area. If you use the outline mode then they are even completely different shapes (they are edges rather than polygons).

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Hope that explains it and doesn't make it more confusing. The two are different concepts.

gilded sparrow Jan 12, 2020, 3:04 PM

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Yep. Got it.
I guess it's just from the "Composite needs RB" that i assumed it's related. But they're not. Cheers

glacial jolt Jan 13, 2020, 4:22 AM

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got an issue with calculating velocities when joints are involved, drinks are on me (forever) if anyone knows the solution: https://forum.unity.com/threads/precisely-controlling-velocity-of-rigidbodies-that-are-using-joints.808308/

Unity Forum

Precisely controlling velocity of rigidbodies that are using joints

I am working on a VR project where the player has physical hands that directly interact with the world. Previously, the hands were a single rigidbody...

native plover Jan 13, 2020, 9:30 AM

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So im making an FPS character controller. I haven't added anything to do with gravity, but my player is falling anyway. What can be causing this?

tight leaf Jan 13, 2020, 10:02 AM

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So you didn't add a RigidBody to your Player?

tardy sapphire Jan 13, 2020, 6:53 PM

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I have a boxcollider2d set as is trigger that detects if my player runs through it but if I go to fast I just go right through it and it doesn't detect anything I need some help

marsh portal Jan 13, 2020, 7:01 PM

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I've had the same problem both in 2D and 3D. I think it's something behind the scenes in Unity (my most plausible theory is that if something is going fast enough it "slips in between" of the times that Unity checks for a collision, although if all calculations are done each frame, that wouldn't be the case)

tardy sapphire Jan 13, 2020, 7:52 PM

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I'm doing this in 2d and I wish I could find a fix as it's needed for my game

sly violet Jan 13, 2020, 8:25 PM

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IIRC, the various things you can do to prevent the time step from skipping collisions - e.g. continuous collision detection - don't work for triggers. So it's possible for fast moving objects to just skip over the trigger collider if they're going fast enough, and there's not a simple fundamental solution.
You can make the trigger larger.
You can use some type of raycast or sweepcast in code.
You can even reduce the time step.

tardy sapphire Jan 13, 2020, 8:34 PM

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I think a better solution is for me to limit speed currently you can build up infinity speed so yeah that will probably fix it as building infinite speed isn't necessary

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And I already know how I'm gonna limit speed so no worries about that

sly violet Jan 13, 2020, 8:43 PM

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There's a Max Translation Speed (and Max Rotation Speed) in the Physics 2D Project Settings.

tardy sapphire Jan 13, 2020, 10:25 PM

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I use addforce so I'm not sure if that applies to that

rugged mulch Jan 13, 2020, 10:32 PM

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Would anyone have an idea of how to deal with this challenge. I would like the camera to go the direction of its z-axis local reference but not following it. That is to say, staying in a constant y-axis value.

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📎 unknown.png

glacial jolt Jan 13, 2020, 10:36 PM

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you want to project the Z direction onto the up plane @rugged mulch

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https://docs.unity3d.com/ScriptReference/Vector3.ProjectOnPlane.html

rugged mulch Jan 13, 2020, 10:37 PM

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Thank you! That seems to be exactly what I might need

sly violet Jan 14, 2020, 2:14 AM

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@tardy sapphire I use addforce so I'm not sure if that applies to that
Of course it does, it's simply setting new positions that it wouldn't apply to.

glacial jolt Jan 14, 2020, 9:26 PM

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anyone here used Unity Physics at all? Kind of confused whether DOTS is actually required or not, since there's stuff like:

Modular
Core algorithms are deliberately decoupled from jobs and ECS to encourage their reuse and to free you from the underlying framework and stepping strategy. As an example of this see the immediate mode sample which steps a physical simulation multiple times in a single frame, independent of the job system or ECS, to show future predictions.

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My project doesn't currently use DOTS, but I'm interested in Unity Physics for stateless/determ/open source

lapis plaza Jan 14, 2020, 10:23 PM

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@glacial jolt you need entities package

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but if you look at unity physics samples from dots sample repo, they use it from monobehaviours

lapis plaza Jan 14, 2020, 10:39 PM

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that being said, there are some basic things missing atm

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like, being able to simulate on fixed timesteps out of the box, having interpolated RB's etc

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that is, unless you couple it with dots netcode

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out of the box, unity physics just steps the physics world on each update, using fixed timestep value for sim, making the physics sim faster and slower depending on your framerate

glacial jolt Jan 14, 2020, 11:01 PM

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ahh, that's kinda too bad. I haven't dabbled in DOTS, but I find it a tough sell for a project where performance isn't really a major issue (at the moment, anyways)

split current Jan 14, 2020, 11:17 PM

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@lapis plaza I mean for consoles where you can sort of guarantee the framerate (if you optimise it), it doesn't sound so bad

lapis plaza Jan 14, 2020, 11:22 PM

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there isn't even way to set the physics timestep out of the box

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Unity acknowledges all this, but they are still figuring out the proper way to handle it

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I'm still surprised they haven't done some workaround from day one tho

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because, you can mod it to do both interpolation + fixed timesteps in day or two

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instead they just keep it broken, waiting for official solution for soon full year

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it's kinda situation where everyone just raises hands up and lets the task sit at the end of backlog because it's not the right time for them

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for physics team, I got impression it's not their responsibility but more of regular DOTS framework thing

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and for latter, there's a lot going on with netcode and other stuff where you need to be able to step physics differently from single player games

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here's someones hack for it: https://forum.unity.com/threads/unity-physics-runs-at-diffrent-speeds-depending-on-editor-game-window-size-and-if-its-a-build.804171/#post-5364423

glacial jolt Jan 14, 2020, 11:29 PM

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at least it's open source :S

lapis plaza Jan 14, 2020, 11:29 PM

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that's the main reason I'm looking at it myself 🙂

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I got stuck with Unity's physx implementation due to lack of sources and not getting the feats I need exposed

glacial jolt Jan 14, 2020, 11:30 PM

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I was hoping to upgrade to something open source, since I'm pretty comfy editing physics stuff, but this seems really early

lapis plaza Jan 14, 2020, 11:30 PM

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Unity actually planned to ship this Q3 last year

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nobody really thought it would happen tho

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(talking about Unity Physics, not DOTS itself)

glacial jolt Jan 14, 2020, 11:30 PM

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yeah, pretty sure the InputSystem was due in August

lapis plaza Jan 14, 2020, 11:30 PM

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😄

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yeah, lets not go there again

glacial jolt Jan 14, 2020, 11:31 PM

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👍

jade comet Jan 15, 2020, 8:25 AM

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hey
I want to make a physics based game
where you have to block the path of enemy waves with obstacles. the enemies have to push their way trough those to get to your base and kill you.
is the standard unity physics stuff enough or do I have to download somethign from the store or make my own solution. i have not dealt with more complex/fancier physics stuff yet.

south plover Jan 15, 2020, 7:19 PM

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Anyone know why these entities clipping in builds but not in the editor?

📎 Untitled.png

lapis plaza Jan 15, 2020, 7:29 PM

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@south plover yes

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You probably didnt create/bring link.xml over to prevent ecs stuff from getting stripped in build

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Just copy one from dots sample repos physics examples

south plover Jan 15, 2020, 7:47 PM

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that was suppose to be fixed in 19.3 ... implementing now to test

orchid pelican Jan 15, 2020, 7:47 PM

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@jade comet you could just give the enemies and the obetacles rigebodys and colliders make one obestacles a triger and push it when triggerd

lapis plaza Jan 15, 2020, 7:48 PM

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@south plover I thought so as well but definitely needed that myself still

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@south plover also if you use the recent entities package, you probably need to use the new build system for it

south plover Jan 15, 2020, 8:02 PM

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you talking about the buildsettings thing?

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that might be it

south plover Jan 15, 2020, 9:02 PM

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hmmm I switched to the built in render pipeline and things work.. so this is renderer problem not a physics problem.

south pilot Jan 16, 2020, 4:04 PM

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this was an interesting article from a year back – does anyone know if it'll come into production any release soon? (or what it's status is?) https://connect.unity.com/p/unified-physically-based-audio-rendering-and-the-future-of-audio-in-games

Unity Connect

Unified Physically-Based Audio Rendering and the future of audio i...

Approaching game audio from a different angle

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thought I'd ask in this thread as it might get a wider response than just #🔊┃audio

weary wind Jan 17, 2020, 2:29 AM

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I'm moving my player around with rigidbody.MovePosition() - I move on to a platform that is rotating 360 degrees - I have a script set up to child my player to the platform - however the player can no longer move. If I stop the rotation of the platform however, the player can move. Any ideas?

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I'm not a huge fan of childing the player to each platform anyway, so if I can figure out a solution to not have to do that - that would also be great

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Though at the moment if I don't do that, the player will not move along with the rotation

craggy grove Jan 17, 2020, 2:51 AM

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Hi everyone, I've been working with the Unity Wheel Colliders in 2019.2.17f1. So far, when using them in this game I'm developing, most of the physics behavior is OK, but two things: 1.) When colliding into a hill, I can't climb up it evenly - the car "jitters" back and forth, bounces, etc 2.) When I collide into something like a wall head on at a fast speed, or maybe even fall off a cliff, the car kinda "spirals" clockwise in the air as it falls down. My car has all of the parts like tires, axles, body chassis containing convex mesh colliders to help calculate a more accurate center of mass. Perhaps, however, this isn't accurate enough? Anyone have other thoughts/recommendations? I'm also trying to use things like the "Easy Suspension" script by Anthony Yakovlev, and still have mostly these same issues

sly violet Jan 17, 2020, 5:02 AM

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@weary wind I would avoid reparenting rigidbodies. What you could do is put an empty "ghost" GameObject that becomes a child of the platform. Then, when you move via MovePosition, take into account any movement that's been done by the ghost object, and finally reposition the ghost object (in world space) to the same place your player now is.

weary wind Jan 17, 2020, 5:04 AM

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Yeah, I've actually ended up setting the platform as rigibody, unparented, and rotated the platform with rb.MoveRotation - which works as far as I can tell for positioning

sly violet Jan 17, 2020, 5:04 AM

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If you don't want to do that, technically all the tools needed to accomplish that effect are in the Transform script. In this case, you'd be looking at creating a "RotateAround" call that mimicked the platform.

weary wind Jan 17, 2020, 5:04 AM

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The issue with this now though is the Player's rotation doesn't reflect the rotation of the platform

sly violet Jan 17, 2020, 5:05 AM

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https://docs.unity3d.com/ScriptReference/Transform.RotateAround.html

fair marsh Jan 17, 2020, 7:50 PM

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Are there any optimizations to do in terms of the unity character controller?

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Seeing each update for 1 player taking 1-2 ms 😅

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In a 1k terrain scene with only few colliders

hybrid beacon Jan 17, 2020, 9:18 PM

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you can make your own if you don't need all of the functionality the charController has to offer

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I am getting some super odd behavior using Physics.BoxCastAll(). I am casting down from my player to check for grounded. However when I test on an angled plane, it returns the hit at the origin and with a normal of (0,1,0) as I move across the plane. Any ideas why?

sly violet Jan 17, 2020, 9:52 PM

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Huhhh. Odd. Is the initial position of the box intersecting the plane? Maybe it doesn't like that.

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What kind of collider is the angled plane? I want to replicate.

hybrid beacon Jan 17, 2020, 9:59 PM

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box collider on my player and on the plane (its a stretched cube)

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i move the player to the plane during the run

sly violet Jan 17, 2020, 9:59 PM

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...Are you absolutely sure you're not just picking up the player?

hybrid beacon Jan 17, 2020, 9:59 PM

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yeah i debugged the name of the objects

sly violet Jan 17, 2020, 9:59 PM

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Just checking. 🙂

hybrid beacon Jan 17, 2020, 9:59 PM

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i can provide code/screenshots if you would like

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i can also let you clone my repo if you would like to get the exact conditions 🙂

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i found the issue

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for some reason if i cast down with a distance of 0.01 it doesn't work, but 1 does... My thought was to test the player being barely above the ground

sly violet Jan 17, 2020, 10:10 PM

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Strange.

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I wonder what the minimum is.

lyric storm Jan 18, 2020, 1:06 AM

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Any advice for how to calculate the physics for objects being pulled along a route like a spline

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I have a good spline solution in, one simple enough where I tell it a speed and it'll move an object appropriately along it

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But I'm trying to figure out how I can have something "pull" other things along the same spline realistically

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other things that are on the same spline

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Obviously probably can't use Unity's own physics engine for this

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I may have to end up pretty much writing my own physics around this, just not sure how to even get started figuring this out

lapis plaza Jan 18, 2020, 1:22 AM

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why can't you use built-in physics for that?

lyric storm Jan 18, 2020, 1:28 AM

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I don't really see a way to use physics on a spline like that

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Everything I've seen has suggested otherwise because of all the quirks of the engine in how it interacts with things and how I'd have to constrain objects to it.

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Unless I constrain objects to the spline, ignore collisions, and only use raw forces to push items?

lapis plaza Jan 18, 2020, 1:46 AM

#

so you mean you have to contrain the objects strictly along the spline?

#

if that's the case, then calculating your own physics might not be that hard

#

if you just need the objects get attracted to the spline location, that's doable with any physics engine

lyric storm Jan 18, 2020, 1:49 AM

#

I need them to be constrained to the spline, including orientation

#

I can imagine very abstractly how to do my own physics on it but am having trouble figuring how how to even get started on it, how to write physics for that

#

Or I wonder if I can grab and outside forces but apply them only along the tangent of the spline

#

I also keep imagining doing just 2D physics where the two axis to solve for are X and Y along the spline

#

This is suggesting they got this kind of solution with a Configurable Joint

#

http://stettj.com/unity-spline-physics-constraint

craggy grove Jan 18, 2020, 2:35 AM

#

Hi everyone, I've been working with the Unity Wheel Colliders in 2019.2.17f1. So far, when using them in this game I'm developing, most of the physics behavior is OK, but two things: 1.) When colliding into a hill, I can't climb up it evenly - the car "jitters" back and forth, bounces, etc 2.) When I collide into something like a wall head on at a fast speed, or maybe even fall off a cliff, the car kinda "spirals" clockwise in the air as it falls down. My car has all of the parts like tires, axles, body chassis containing convex mesh colliders to help calculate a more accurate center of mass. Perhaps, however, this isn't accurate enough? Anyone have other thoughts/recommendations? I'm also trying to use things like the "Easy Suspension" script by Anthony Yakovlev, and still have mostly these same issues
Hey guys, any further thoughts on this?

sly violet Jan 18, 2020, 3:19 AM

#

@lyric storm Do you have a good way to detect the closest point of the spline? Have a kinematic "ghost" object that always exists at the closest point and rotation of the spline and then make a "slider" joint out of a configurable joint between the ghost object and the, uh, train object.

drifting ridge Jan 18, 2020, 4:19 AM

#

Anyone have any good tutorials for active rag doll physics and animating them?

mighty sluice Jan 18, 2020, 5:38 AM

#

Anyone tried articulations yet?

#

im looking for some resources about best practices when making big complex articulation trees

#

(e.g: if i want to affix four articulation bodies into a rigid square with 4 corners, what should the parent/child structure look like for best results?)

#

the options are like:
-one central articulationBody with 4 children

one corner as the root, and the others extending around vertices as children/grandchildren

#

i realize merely making a fixed square is something that doesn't require joints or articulations, but for more complex articulation trees, knowing the best approach is relevant

mighty sluice Jan 18, 2020, 6:40 AM

#

Also, should I be centering the colliders, or should I move the pivot point over to the anchor point?

#

and what of collisions between parent and child colliders?

mighty sluice Jan 18, 2020, 7:45 AM

#

(collisions seem to not be a thing between parent and child articulation bodies, which is good

autumn jetty Jan 18, 2020, 5:00 PM

#

My physics object I convert get rotated it seems 90 degrees 😂 Anyone have any clue to what could cause this?
(fixed) How about use the EntityQuery when scheduling job x)

#

📎 unknown.png

craggy pivot Jan 18, 2020, 5:37 PM

#

Some help please

#

My player dont detect colision with the terrain

#

What i need to do?

marsh shuttle Jan 19, 2020, 3:57 AM

#

Hello guys, any way to disable gravity in a PhysicsBody in the Ecs physics? I looked at pyshics body while keeping all the other things on the object like in the normal RigidBody

#

Nevermind me guys, anyone interested look at PhysicsGravityFactor component

polar citrus Jan 19, 2020, 4:08 AM

#

@craggy pivot box collider?

cobalt crest Jan 19, 2020, 5:39 AM

#

hey there, I'm having some weird trouble where it's really difficult (very jittery movement) to move around in this hallway mesh I've made and I'm not sure what to do

#

Currently I have the floor and walls be one mesh. Should they be instead seperate meshes?

cobalt crest Jan 19, 2020, 6:27 AM

#

ah, I found my problem. I was colliding with the ceiling

hazy fiber Jan 19, 2020, 5:23 PM

#

how can i fix this

📎 2020-01-19_18-09-53.mp4

dapper wigeon Jan 19, 2020, 8:28 PM

#

Hey forum! ^^

How can I make a landed "rocket" move with a constantly rotatiing planet? I realized I have to use .AddTorque() and not just rotation, but this keeps adding rotational speed to the planet.

📎 planet_rotation.jpg

#

Wow, I actually figured it out, using .MoveRotation() instead

stuck bay Jan 19, 2020, 8:56 PM

#

When I add a polygon collider 2D component to an attack sprite my game freezes. When I remove the component it moves forward like it should but will not hit the enemy.

#

Is there any way to fix this?

azure ruin Jan 19, 2020, 9:49 PM

#

hey

#

i am really new to unity and i need to program with c sharp or something. i have microsoft visuals but i dont own the c sharp script or something. it doesnt get the thing that i wanna type like xRotation = Mathf.Clamp(xRotation, -90f, 90f)

#

like the colors

unkempt totem Jan 19, 2020, 9:52 PM

#

Hi, can anyone help me keep my ragdoll in 2d bounds? using 3d physics but want to keep my ragdoll frozen in the x and y rotation and the z position. If I just freeze those on the rigidbody component it spazzes out so that doesnt help, any suggestions? (Using config joints) https://i.imgur.com/u0v8uKf.png

Imgur

mighty sluice Jan 20, 2020, 10:01 PM

#

is there any way to set the inertia tensor of an articulation body?

#

ah found it

#

it has tis own set metho

#

method*

marsh shuttle Jan 21, 2020, 1:27 AM

#

https://hastebin.com/ihekivajuv.cs
The issue is that i set the lifetime to be based on a maxAttackRange/Speed after debugging it the initial lienar speed for PhysicsBody is set to the correct values on creation, but the bullet always goes further than what maxAttackRange says it shoud be, like for about a half
And here it is how I'm creating the bullet https://hastebin.com/ovaciqesoq.cs ```

I wrote a simple move by speed and acceleration, and it indeed works as expected with the timings. I'm unsure what I'm doing wrong with PhysicsVelocity component as I'm setting the Linear speed here but the object moves faster than It should be.

I have as well debugged in the Entity Debugger and the magnitude of LinearVelocity matches the desired speed but the object still moves faster than what it should.

Any help with this?

crisp island Jan 21, 2020, 3:18 AM

#

@marsh shuttle did you try logging the float3 speed (which you should probably rename to vel) to ensure it's what you expect

#

I'm not sure what you mean by "faster than it should be"

marsh shuttle Jan 21, 2020, 3:51 AM

#

@crisp island yes I tried logging it, about the naming speed VS velocity I usually go with speed because less characters but never thought of vel.

What I mean by moving faster than it should is that I instantiate the entity give it a position and a velocity and by that velocity the object should reach certain point in certain time, but it does get past the object by 50% of the expected travel distance by that time, I have set a gravity factor of 0 and a linear damping of 0 too

crisp island Jan 21, 2020, 3:56 AM

#

what velocity did it log and what travelled distance did you measure after what duration

marsh shuttle Jan 21, 2020, 4:17 AM

#

I have it set to travel 10 units in 2 seconds so the float3 gave a velocity in the range of (4.999983,0,-0.000027) in other words the magnitude was 5, this meant that that the speed was 5 units/second but after two seconds the object finishes by the mark of 15 units

#

Sorry if answer late, I'm away of my pc right now I can provide the unity project so you can look at it if you are interested in it.

I have a cube in scene that is controlled by the keyboard and its moves speed is of 5 units/second (I have set it to kinematic Physics Body) and by adding to Translation.Value += vel * deltaTime it moves as it should.

While the PhysicsBody from Unity.Physics that handles the movement of the bullet(I even debugged the bullet in the Entity Debugger and the Linear Velocity component of it had a magnitude of 5), then I cannot think of why the bullet ends at 15 units after 2 seconds, I tried to find how the pyshics system to see how the linear velocity adds up(yet haven't found the actual job that does it) so I have no luck with this

marsh shuttle Jan 21, 2020, 6:35 AM

#

I've actually created a thread on the forums with better information and explanation for anyone interested https://forum.unity.com/threads/unity-physics-physicsvelocity-does-not-reflect-the-current-velocity-of-the-physics-body.813036/

Unity Forum

[Unity.Physics]PhysicsVelocity does not reflect the current veloci...

Hello.

I have been playing with ECS and now I'm transfering that to Unity.Physics. I tried to ask this in the discord server but didn't got much help...

naive remnant Jan 21, 2020, 7:46 AM

#

@marsh shuttle Unity Physics uses 'UnityEngine.Time.fixedDeltaTime' to step simulation, but the system itself updates every frame. I bet this is the problem.

marsh shuttle Jan 21, 2020, 7:49 AM

#

@naive remnant I'm using the preview package, and the default physics systems so I have not defined which delta does the simulation uses, nor if its running every frame

naive remnant Jan 21, 2020, 7:51 AM

#

force physics system to update in fixed steps or at at least at normal delta time

marsh shuttle Jan 21, 2020, 7:56 AM

#

So I should get the system inside a MonoBehaviour and Call its Update() method manually?

naive remnant Jan 21, 2020, 8:01 AM

#

you can move SimulationSystemGroup(SSG) to Unity's internal FixedUpate, or you can edit some files in entities package and make SSG update at regular intervals internally

#

or you can make physics package use normal delta time, but it will be kinda unstable

marsh shuttle Jan 21, 2020, 8:04 AM

#

Reading this it looks like it already runs in FixedUpdate https://forum.unity.com/threads/why-is-simulation-the-default-system-group.639058/

Unity Forum

Why is Simulation the default system group?

In regular Unity you use Update for the game logic while FixedUpdate is recommended for physics-related things. Is this different in ECS? Why?

#

ups, this link https://forum.unity.com/threads/why-is-simulation-the-default-system-group.639058/#post-4289911

Unity Forum

Why is Simulation the default system group?

In regular Unity you use Update for the game logic while FixedUpdate is recommended for physics-related things. Is this different in ECS? Why?

naive remnant Jan 21, 2020, 8:06 AM

#

no it is not, it is in regular update loop but uses fixedDeltaTime to step simulation

#

so every frame it advances simulation by 0.02s

#

no matter the framerate

#

faster framerate = faster movement

marsh shuttle Jan 21, 2020, 8:08 AM

#

Okay then I should work on my lecture comprehension skill, I though it said it was on fixed update

naive remnant Jan 21, 2020, 8:08 AM

#

it was some time ago

marsh shuttle Jan 21, 2020, 8:09 AM

#

Point me towards the correct method in the api to do this: you can move SimulationSystemGroup(SSG) to Unity's internal FixedUpate and I will work it out

naive remnant Jan 21, 2020, 8:11 AM

#

i have to make your custom 'ICustomBootstrap' 😅

#

easiest and fastest way for you is just edit 'StepPhysicsWorld.cs'

#

#if !UNITY_DOTSPLAYER
            float timeStep = UnityEngine.Time.fixedDeltaTime;
#else
            float timeStep = Time.DeltaTime;
#endif```

#

into this cs ///#if !UNITY_DOTSPLAYER /// float timeStep = UnityEngine.Time.fixedDeltaTime; ///#else float timeStep = Time.DeltaTime; ///#endif

marsh shuttle Jan 21, 2020, 8:16 AM

#

I found it, Wouldn't it be easier to change the update group in RunTime if possible? like for example at the Convert phase of some IConvertGameObjectToEntity

#

rather than make a ICustomBootstrap

naive remnant Jan 21, 2020, 8:17 AM

#

maybe, but i don't know how

#

and if you make physics system update in fixed steps, you will need some sort of interpolation system

marsh shuttle Jan 21, 2020, 8:20 AM

#

I will go with the change to Time.DeltaTime for the time being, then if they did change this to be updated each frame to not create an intepolation system(yet or maybe never) Why was left it so UnityEngine.Time.fixedDeltaTime in use?

naive remnant Jan 21, 2020, 8:24 AM

#

in the link you posted,engineer who worked on this explained why they moved simulation systems to regular Update

marsh shuttle Jan 21, 2020, 8:25 AM

#

I did read that comment, but did not find why they are still using fixedDeltaTime

#

Other thing I changed StepPhysicsWorld.cs to use Time.DeltaTime but does not seem to have an effect do i need to take any extra step?

naive remnant Jan 21, 2020, 8:33 AM

#

📎 Unity-ECS-TEST-master_-_SampleScene_-_PC_Mac__Linux_Standalone_-_Unity_2020.1.0a19.2395_Personal_PRE.mp4

#

is this how you wanted it to be destroyed?

marsh shuttle Jan 21, 2020, 8:37 AM

#

Yes, I put the cube there as a measure of the 10 units so I knew i was just not being crazy, As well i reviewed my inspector and for some reason the values of the object in the scene where resetted to 20 now it looks to work but goes a bit further than the cube it may be that the cube is not at 10

#

10 units from the spawn

#

but in your video it does inded stop inside the cube where the 10 units mark from the spawn is

naive remnant Jan 21, 2020, 8:39 AM

#

and you will need to edit StepPhysicsWorld.cs every time you open you project

#

or make Unity.Physics package local

marsh shuttle Jan 21, 2020, 8:39 AM

#

wow

#

btw what did you do in the video? just changed it to Time.DeltaTime?

naive remnant Jan 21, 2020, 8:40 AM

#

yes

#

i just edited StepPhysicsWorld.cs

marsh shuttle Jan 21, 2020, 8:42 AM

#

gotcha, sometimes it goes a bit further and sometimes it doesn't I guess it's because of it being unstable due to a variable timeStep?

#

how would I make the package local? deleting the reference from Packages.json and copying the folder to the assests folder?

naive remnant Jan 21, 2020, 8:45 AM

#

you can just copy you package from 'YourProject\Library\PackageCache' to '\Packages'

marsh shuttle Jan 21, 2020, 8:47 AM

#

I see

#

I just realized that it goes a bit further because for some reason after shoting the bullet the physics body in the player goes a bit further which is weird as I have set IsTrigger to true on the bullet prefab

#

and the player physics body is set to kinematic

#

nevermind me It was resetted to dynamic for some reason too

#

and it works perfectly now, thank you

#

Do you mind posting your answer into the unity forums? it may be helpful for someone else aswell

#

Night and thank you again

crisp island Jan 21, 2020, 2:32 PM

#

how does one create a PhysicsCollider component (ecs) via code?

#

I'm trying to create a simple box collider for each tile in my 2d tilemap, since no ecs tilemap collider seems to exist yet

#

nvm, according to https://docs.unity3d.com/Packages/com.unity.physics@0.2/manual/core_components.html it seems that Unity.Physics.BoxCollider.Create() is what I'm looking for

crisp island Jan 21, 2020, 4:07 PM

#

where/how do I see the ecs physics debug display?

naive remnant Jan 21, 2020, 4:36 PM

#

Add Physics Debug Display component to some entity

crisp island Jan 21, 2020, 5:09 PM

#

I did, nothing appeared to happen

#

@naive remnant

#

checked all the draw boxes, and the GO has the Convert to Entity script set to "convert and destroy", and a Physics Shape and Physics Body

#

also tried creating an entity through scripting and using AddComponentData() to add a PhysicsDebugDisplayData component to it, still nothing

naive remnant Jan 21, 2020, 5:12 PM

#

maybe try without Physics Shape and Physics Body 🤔

crisp island Jan 21, 2020, 5:13 PM

#

like replace them with a box collider and rigidbody?

#

no difference

#

the debug display component sounds useful but apparently is quite mysterious

naive remnant Jan 21, 2020, 5:13 PM

#

empty entity with PhysicsDebugDisplay

crisp island Jan 21, 2020, 5:14 PM

#

nothing

#

it's unfortunate because it would be nice to visually see the PhysicsColliders for my tilemap I'm creating in code

#

I wonder if they put the authoring component in the package but it's just currently unused by any system

naive remnant Jan 21, 2020, 5:20 PM

#

But it kinda works in my projects

crisp island Jan 21, 2020, 5:22 PM

#

how on earth

#

the debug graphics show up in the scene view? and you don't need any other windows open?

#

just one single empty gameobject in your scene with the component?

naive remnant Jan 21, 2020, 5:25 PM

#

PhysicsDebugDisplay and ConvertToEntity on a single empty gameobject

crisp island Jan 21, 2020, 5:25 PM

#

oh, it worked

#

I apparently had another one on a different GO that I forgot about which had nothing checked

#

I'm guessing the system just uses the first one it finds and ignores all the rest

#

thanks for your help

jovial creek Jan 21, 2020, 8:55 PM

#

I'm not quite sure if this qualifies as a physics specific question but it involves collisions etc. I'm trying to populate a list with all the objects a building block is in contact with when placed but it only ever does the first object, I've tried a foreach (ContactPoint contacts in collision.contacts) etc. but it just does it for each contact point on the collision with the first object

jovial creek Jan 21, 2020, 10:44 PM

#

I kind of found a workaround (rather than have the building block being placed populate it's list I have the building blocks it touches do it)

crisp island Jan 21, 2020, 11:22 PM

#

what's a clean way to make a system that "2D-ifies" the new unity physics? (prevents translation along the z-axis and rotation along the x- or y-axes)

#

i.e. something like the Constraints checkboxes of the classic rigidbodies

#

I feel like just zeroing those values out each frame isn't going to be ideal since it doesn't properly deal with correcting angular and linear velocity

open blade Jan 22, 2020, 12:01 AM

#

Hi, does anyone have ideas on how to create a more accurate mesh for PolygonCollider2D using SpriteShape?

📎 test.png

placid mortar Jan 22, 2020, 12:16 AM

#

Hi ppl... I'm trying to add a Wheel Collider to a car 3d model, but the circle is in a different rotation. How can I fix it?

jovial creek Jan 22, 2020, 2:40 AM

#

whenever I have a problem with rotation not matching I just make the object a child of an empty game object (but I still have problems from time to time) like I would suggest your car model and wheel be children of an empty game object

#

@placid mortar forgot to tag ya

placid mortar Jan 22, 2020, 2:41 AM

#

Thank you 😉

proud condor Jan 22, 2020, 3:36 AM

#

Not sure if it's a right channel to ask but anyone here worked with flowfield pathfinding?

mild adder Jan 22, 2020, 4:39 AM

#

Hi, I'm a beginner trying to create a simple fps controller with a sense of momentum, so I am using a rigidbody with addforce. The controller feels weird on the ground when trying to change directions, though, because the player has to slow down and then accelerate the other direction. Is there a simple fix for this?

naive remnant Jan 22, 2020, 5:10 AM

#

@crisp island look at Physics samples, in the joint section there is Limit DOF join. It is doing exactly the thing you want

crisp island Jan 22, 2020, 5:34 AM

#

@naive remnant thank you, I hadn't noticed it

sly violet Jan 22, 2020, 6:26 PM

#

@mild adder I mean, that's what "a sense of momentum" means, if you can just turn on a dime that's the opposite of momentum.
That being said, you might try cranking up the drag and/or friction. (You'll have to up the force to compensate.) This presents a bias towards being able to stop quickly, which is both realistic and might help it "feel" better.

hushed oasis Jan 22, 2020, 6:47 PM

#

Guys , Is there a way to change position of center of mass of an object in Unity

waxen edge Jan 22, 2020, 7:04 PM

#

hey people, i have a question
i want to be able to throw objects to the point i clicked with my mouse, but how do i know the power i need to let the thrown object travel exactly the needed distance?

ocean horizon Jan 22, 2020, 7:08 PM

#

@hushed oasis Docs: https://docs.unity3d.com/ScriptReference/30_search.html?q=center+of+mass

naive remnant Jan 22, 2020, 7:16 PM

#

@waxen edge https://www.youtube.com/watch?v=v1V3T5BPd7E&list=PLFt_AvWsXl0eMryeweK7gc9T04lJCIg_W

YouTube

Sebastian Lague

Kinematic Equations (E01: introduction)

This video introduces the 5 kinematic/suvat equations, and shows an example of their usage in the context of video game development. It also covers how the equations can be derived.

If you'd like to support these videos, you can make a recurring monthly donation (cancellable...

▶ Play video

waxen edge Jan 22, 2020, 7:33 PM

#

@naive remnant great thank you very very much

royal stag Jan 22, 2020, 8:15 PM

#

How can i make my player slide down this ramp, i have a slippy material on the ramp and fcource gravity on the player

📎 unknown.png

mild adder Jan 22, 2020, 9:56 PM

#

@sly violet Thank you for the advice. I guess I'm trying to achieve a controller that feels like a typical FPS controller where it's very responsive on the ground, but when you jump or take some other action in the air, you have a sense of momentum. I'll try messing with drag and friction though, thanks.

mild adder Jan 22, 2020, 10:13 PM

#

I'm trying to shoot a projectile that stops when it hits an object. It works just fine, except for the fact that when the object is instantiated, it stays still unless my player touches it, then it shoots forward. What's a possible reason for this? It has a rigidbody and it's non kinematic (bc I want it to collide with the environment and then stop when it hits)

naive remnant Jan 22, 2020, 10:15 PM

#

@mild adder https://catlikecoding.com/unity/tutorials/movement/physics/ maybe this will help you with your controller🤔

Physics

A Unity Movement tutorial about controlling a rigidbody sphere.

mild adder Jan 22, 2020, 10:17 PM

#

@naive remnant Ty, I'll take a look at it!

sly violet Jan 23, 2020, 1:53 AM

#

It works just fine, except for the fact that when the object is instantiated, it stays still unless my player touches it, then it shoots forward. What's a possible reason for this?
Umm... Are you adding a velocity or force to it upon instantiation, or not until your player touches it?

lapis orchid Jan 23, 2020, 4:35 AM

#

Hi, I have a very weird issue. I'm trying to make a small online kart game, and when I preview everything works fine

#

However, when I build the game and hit play, my player and every other phsyics object fall through the floor

#

I don't think it's linked to Photon (it would make no sense)

viral swallow Jan 23, 2020, 9:03 AM

#

Hey all, is there a way to stop a rigidbody child from inheriting parent movement?

#

trying to make a 1st person fishing setup, where the rod and lure are parented to the camera, but I want the lure to just be hanging connected by a joint

hollow echo Jan 23, 2020, 9:08 AM

#

It might make more sense to not have the lure under the camera and to just use a position constraint to form the relationship with the end of the rod

#

Or a fixed joint

viral swallow Jan 23, 2020, 9:11 AM

#

mmm had issues with having it separate

#

because the player gets teleported around

#

(presumably)

#

I'm not sure exactly, but prob should try another solution

hollow echo Jan 23, 2020, 9:13 AM

#

If you do do teleporting you probably would need to do something like rigidbody.position += relativeMovement; to avoid things freaking out

autumn jetty Jan 23, 2020, 9:26 AM

#

For the new physics system, anyone know what would be more performant. Having different layered (non touching) in the same place (i.e. they will overlap but never collider), or same layered spaced apart?

bleak coral Jan 23, 2020, 11:01 AM

#

guys, i have this setup
Spaceship
Spaceman inside Spaceship
I want them to move inside the spaceship as it was a fixed frame, spaceship movement "doesnt" affect them in any other way, than translating them in world position in the same rate as the spaceship.
my spaceship is rigidbody kinematic i change its position with the velocity prop
the spaceman are children of the spaceship and are rigidbody dynamic, their velocity is movement velocity * move speed + spaceship velocity
but if i turn the ship around it goes weird (understandable)
Whats the correct way for that approach?

#

pls ping me so i can see the answer

autumn jetty Jan 23, 2020, 11:50 AM

#

@bleak coral If you work in localspace and not worldspace for your player movement it should work fine

bleak coral Jan 23, 2020, 11:51 AM

#

@autumn jetty how should that work fine if rigidbodys are calculated in world space?

#

like, if i only add velocity to the rigidbody, it "falls behind" while movin the ship

autumn jetty Jan 23, 2020, 11:52 AM

#

I see, if you're using rigidbody for the character it is a bit more problematic

#

I have kind of same thing with spaceship and player on it, but I have spaceship as rigidbody and player as kinematic character controller.

#

My current solution is in DOTS and don't think it translates well back. But in the old system what I came up with was to have a local phyiscs representation that has a separate layer but no graphics, and then a visual one that is parented to the moving spaceship.

#

You might also be able to store the previous frames velocities and current frame, and recalculate the state of the rigidbody of the characters before you do any movement.

final oak Jan 23, 2020, 3:16 PM

#

hello! im working on a topdown 2d rpg and started running into this problem where my character's movement would be really jerky, its smooth at first but then it only seems to happen after I let the game idle for some time. initially i thought it was because i ran the movement through fixedupdate and multiplied the speed by time.fixeddeltatime, but regular update is resulting in the same jerky motion.
here's a condensed version of my player controller and a vid

using UnityEngine;

public class PlayerController : MonoBehaviour
{
    Rigidbody2D body;

    float horizontal;
    float vertical;

    public float walkSpeed = 250f;
    public float runSpeed = 500f;
    private float speed;

    void Start()
    {
        speed = walkSpeed;
        body = GetComponent<Rigidbody2D>();
    }

    void Update()
    {
        horizontal = Input.GetAxisRaw("Horizontal");
        vertical = Input.GetAxisRaw("Vertical");

        if (Input.GetButton("Fire3"))
        {
            speed = runSpeed;
        }
        else
        {
            speed = walkSpeed;
        }

        body.velocity = new Vector2(horizontal * speed * Time.deltaTime, vertical * speed * Time.deltaTime);
    }
}

📎 nKuduDUqZX.mp4

ocean horizon Jan 23, 2020, 3:20 PM

#

@final oak Because the physics system doesn't run per-frame unless you're setting it to do that. Update is called per frame render. Physics only updates per fixed-update which by default is 50hz. Also, you're setting velocity but scaling that by the frame-delta which makes no sense as the physics system will integrate velocity into changes in position.

final oak Jan 23, 2020, 3:21 PM

#

Gotcha, thanks!

ocean horizon Jan 23, 2020, 3:22 PM

#

If you want to keep the physics updating during the fixed update then you need to Set the Rigidbody2D to use interpolation. Then in a FixedUpdate callback you can set the velocity directly if you like.

#

Note that setting the velocity directly will stomp over any body velocity changes the physics system might make such as linear drag, gravity (probably not used here) or more importantly, changes due to collisions.

#

In the FixedUpdate you can calculate a position to move using body.MovePosition(body.position + new Vector2(horizontal, vertical) * speed * Time.fixedDeltaTime)

#

The way you do this depends on decisions on when you want the physics system to run.

final oak Jan 23, 2020, 3:26 PM

#

thanks so much! the moveposition method seems to feel a lot better so i dig it

ocean horizon Jan 23, 2020, 3:28 PM

#

It'll only be smooth though if you turn on Rigidbody2D interpolation. If you call MovePosition from Update then note it won't be actioned until the next fixed-update happens and there can be several frames before that happens. It'll only use the last one.

nova hatch Jan 23, 2020, 4:06 PM

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Hey does anyone has a tutorial to make something like this https://youtu.be/Sfrdb2tZQJY

YouTube

Kévin Drure

[Unity] Flight Camera Character Controller: quaternion based

3C on flight behaviour for Unity.

More here: http://kevind-portfolio.blogspot.fr/2015/10/unity-flight-camera-character-controller.html

▶ Play video

crisp monolith Jan 23, 2020, 6:57 PM

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@royal stag You can use rigidbody and the player would automatically slide if i'm not wrong

worthy grotto Jan 24, 2020, 3:04 PM

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Good morning. Is there anyone online that I can speak with today?

nova hatch Jan 24, 2020, 3:19 PM

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Ye

worthy grotto Jan 24, 2020, 3:37 PM

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Great. So, I'm looking for a recommendation for a code/script that can handle real time, direct volume rendering. Kind of like the tech that is being used to generate medical scans for patients, but it doesn't have to produce see-through slices of the interior of a piece of geometry. In your opinion, would this be something that Unity could handle working with?

nova hatch Jan 24, 2020, 5:55 PM

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I didn't quite get everything

#

UnityChanBusy

worthy grotto Jan 24, 2020, 6:04 PM

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Would an example of what I'm shooting for help @nova hatch ?

ocean horizon Jan 24, 2020, 6:12 PM

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@worthy grotto I used to work in the medical, security and industrial inspection industry doing non-destructive inspection and producing 3D models from various data-sets. Unity is capable of using 3D volumetric textures and shaders used to present them in various ways so the answer would have to be yes. There's also the DOTS stuff which would enable you to write pretty efficient parallel CPU code but it also has compute shader capability too to get access to even more processing power. Please note that this isn't a physics simulation question which this channel is focused on and you're more likely to get an answer in #archived-shaders or #💻┃code-beginner as it's more of a graphics/presentation question, assuming I've followed your question.

worthy grotto Jan 24, 2020, 6:54 PM

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@ocean horizon I'd say you're following it quite well. I came here as per the suggestion of someone that I was speaking to yesterday evening in the #💻┃code-beginner discussion area. So with this in mind, could we continue this discussion in #archived-shaders ? I would really like to get some more of your input on the matter.

stiff topaz Jan 24, 2020, 6:59 PM

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Does anyone know how to set my PPU in the editor and my sprites so that physics works right?

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so the physics are proportional to my sprites

ocean horizon Jan 24, 2020, 7:19 PM

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@worthy grotto Honestly, I'm a physics guy and my knowledge about compute shaders etc inside Unity is very limited. I would suggest asking specific questions and seeing who knows.

worthy grotto Jan 24, 2020, 7:23 PM

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@ocean horizon I see. Then I take my questions over to the shaders discussion. Thank you for replying back to me, though. That was real nice of you, and I appreciate it.

stuck bay Jan 24, 2020, 8:47 PM

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How should I go about making this https://github.com/LiquidStudioGames/AREA/blob/master/Area Game Files/Assets/Scripts/Core/Player/PlayerMovementFixed.cs a rigidbody based movement using Addforce only?

GitHub

LiquidStudioGames/AREA

AREA - A futuristic fast-paced FPS. Contribute to LiquidStudioGames/AREA development by creating an account on GitHub.

onyx cave Jan 25, 2020, 8:24 AM

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i have player and grass set up like this, one is rigidbody collider another is static trigger collider, i have my logic written in OnTriggerEnter2D aswell as in OnColliderEnter2D and tried both, neither detects collision, what could be the problem?

📎 1.PNG

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📎 2.PNG

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nvm i forgot to attach script to grass

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😩

hearty timber Jan 25, 2020, 4:03 PM

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does anyone have any thoughts why I cannot get smooth movement for my character? I'm trying to move a 2D sprite on a 3D plane and it keeps getting blurred when i move

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I'm moving in fixedupdate etc

stable shadow Jan 25, 2020, 6:47 PM

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have you changed up the friction on the physics material?

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oh for a sprite.. have you tried different texture filtering?

stuck bay Jan 25, 2020, 8:58 PM

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Is there a way i can increase the power or Weight/Mass of my sword that when i hit an enemy he fly away?

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like he get blown away

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any1 can help? and t hanks ❤️

rough basin Jan 26, 2020, 1:21 AM

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Why do i get this with convex mesh colliders on some fbx that i export from blender?

📎 Untitled.png

sly violet Jan 26, 2020, 1:23 AM

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Looks like they're really small?

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Physics are not scale invariant, and when it makes the colliders, it tries to minimize the complexity, particularly of small details. So when you get really small objects, you see stuff like that, where it's badly oversimplified because the vertices are just too close together.

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You might try importing them as something larger, and then shrinking the scale in Unity after the collider is generated. I think that works.

rough basin Jan 26, 2020, 1:27 AM

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ah.. that might be the problem. i didn't think that mattered

sly violet Jan 26, 2020, 1:28 AM

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Might ping melv to see if there's a way to change how they're generated. I know a lot of the scale variance in Unity is actually exposed and modifiable, but I'm not sure if that will change how the colliders are generated.

rough basin Jan 26, 2020, 1:30 AM

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ill just make it larger on import, that seems to fix it. Thank you

waxen edge Jan 26, 2020, 4:35 PM

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Hey people, I have a question..
I recently found a video series by Sebastian Lague, it's about Kinematic Equations. I could solve a problem I was having by following one of the videos, but I'd like to learn more about Kinematic Equations, does anybody know good resources for that?

jagged marlin Jan 26, 2020, 7:08 PM

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I am trying to make a flappy bird type game where when I die I get sent back to the menu. But when I click start again the player keeps the downward velocity from the round before making it impossible to regain control of the bird because it falls out of the scene almost immediately. help?

sly violet Jan 26, 2020, 9:39 PM

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You can stop this by setting Rigidbody.velocity to Vector3.zero upon restart.

loud rune Jan 26, 2020, 10:21 PM

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Hi everyone! There is a lot of debate on the internet about the Pixel Per Unit affecting the Unity 2D Physics. So my question is, if I set my PPU to 1 for all my assets, will this cause me trouble using Unity Physic Engine?

tardy depot Jan 27, 2020, 12:36 AM

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Hello I'm having some issues with my movement code using rigedbody2D. For moving I use a Vector2 .MovePosition code, but for Jumping I use a .AddForce code. Both codes work as intended separetly but when they're together the .MovePosition code makes the other one not work at all, while the move one works fine.
I think that the Vector2 Y-axis is the one causing this problem (It's set to 0), I just don't know how to fix it.
Edit: I can send you the code I a private message to avoid spamming.

dull cove Jan 27, 2020, 2:34 AM

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Has anyone here every worked with 2D pathfinding on platformers?

sly violet Jan 27, 2020, 4:56 AM

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@loud rune Physics is scale-variant and, by default in Unity, tuned around the notion of man-interactable objects at 1-unit=1-meter. So when you set PPU to 1, you're basically telling Unity that your 32x32 sprite is roughly the size of a medium building. Some of the tuning irrelevant depending on your project, some can be fixed in Unity Physics 2d settings, but others can be harder to work around. By my reckoning, PPU=1 is more trouble than it's worth.

ocean horizon Jan 27, 2020, 9:13 AM

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@tardy depot When you continuously ask the body to go to a position (and NOT let it determine how to move via gravity/forces) then it should be obvious why it's ignoring your forces. This is why typically it's used on Kinematic bodies however in 2D it can be used on dynamic ones. You should also notice that on dynamics where you get gravity, it isn't able to affect a dynamic body if its continuously being asked to move to a specific position so (at least in kinematics) it's why the gravity term is added to the movement position for instance.

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@loud rune As @sly violet stated well, it's not recommended to use 1=pixel as a meter scale. 2D physics uses Box2D and to quote from the Box2D manual, "Box2D works with floating point numbers and tolerances have to be used to make Box2D perform well. These tolerances have been tuned to work well with meters-kilogram-second (MKS) units. In particular, Box2D has been tuned to work well with moving shapes between 0.1 and 10 meters. So this means objects between soup cans and buses in size should work well. Static shapes may be up to 50 meters long without trouble. Being a 2D physics engine, it is tempting to use pixels as your units. Unfortunately this will lead to a poor simulation and possibly weird behavior. An object of length 200 pixels would be seen by Box2D as the size of a 45 story building." You can go beyond this but then you'll find that everything else has to scale up with it resulting in very large forces. You'll also find that gravity seems to cause things to move slowly but that's your scale so you end up massively increasing gravity etc and things start to get out of hand. Often small at first but then you find joints are struggling, you get weird reactions during stacking etc.

tardy depot Jan 27, 2020, 9:29 AM

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@ocean horizon thank you for your reply! In order to mantain gravity I just need to find a way to ask the body to only go somewhere in the X-axis,right? Is there any way to do that?

ocean horizon Jan 27, 2020, 9:32 AM

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Not really. MovePosition doesn't work as a delta position.

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You can calculate the new position including a gravity calculation but know that on a dynamic body, this is just treating it like a kinematic body

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gravity added like this won't affect its inherent velocity

tardy depot Jan 27, 2020, 9:33 AM

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I will try changing it to .velocity instead.

ocean horizon Jan 27, 2020, 9:34 AM

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That won't make any difference as its velocity isn't used if you're continuously using MovePosition.

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MovePosition on a dynamic body means you're taking control of movement so you need to be careful. It's not really that much different than setting velocity directly really.

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There are few golden rules on movement though. In the end, you just need to know what forces you want to affect your body and ensure that whatever you do, you don't stomp over them i.e. gravity, contacts with colliders in the scene etc. MovePosition just does a calc to enable you to move to a specific position but the price is that it has to override velocity for that frame.

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The reason we don't allow gravity to affect a dynamic body using MovePosition is that using it continuously means its velocity gets bigger and bigger forever and a long time ago, when 2D first came in, this was reported (correctly) as a bug.

tardy depot Jan 27, 2020, 9:43 AM

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Thanks a lot! I will check the Unity reference guides to see what fits best what I am looking for, then trial and error.

loud rune Jan 27, 2020, 10:05 AM

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@sly violet @ocean horizon thanks for the information I will most probably go back to 100 PPU and multiply everything by a Constant

stuck bay Jan 27, 2020, 3:04 PM

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future of physics is more like https://www.youtube.com/watch?v=atcKO15YVD8

YouTube

Two Minute Papers

AI Learns To Compute Game Physics In Microseconds ⚛️

❤️ Check out Weights & Biases here and sign up for a free demo: https://www.wandb.com/papers

Their blog post and their CodeSearchNet system are available here:
https://www.wandb.com/articles/codesearchnet
https://app.wandb.ai/github/CodeSearchNet/benchmark

📝 The pape...

▶ Play video

autumn jetty Jan 27, 2020, 3:35 PM

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Comparing results to 2 fps simulation xD

stuck bay Jan 27, 2020, 7:00 PM

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any physics gurus out there? I'm having troubles with making sinusoidal movement

glacial jolt Jan 27, 2020, 8:05 PM

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@stuck bay like having an object move along a sine wave?

stuck bay Jan 27, 2020, 8:06 PM

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yes, for some reason it doesn't move right, it looks like this

📎 unknown.png

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(instantiated 2 with opposite signed amplitudes so it's more visible)

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my script looks lke this private void FixedUpdate() { time += Time.fixedDeltaTime; sideVelocity = wave * Mathf.Cos(time * frequency) * amplitude; rb.velocity = forwardVelocity + sideVelocity; }

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where forwardVelocity is where it was originally fired to, and wave is perpendicular to it

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Sin for some reason has correct wave (shape-wise), but not the one im trying to achieve

glacial jolt Jan 27, 2020, 8:11 PM

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looks legit

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📎 unknown.png

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    {
        time += Time.fixedDeltaTime;
        Vector3 sideVelocity = transform.up * Mathf.Cos(time * freq) * amplitude;
        GetComponent<Rigidbody>().velocity = Vector3.right + sideVelocity;
    }```

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modified a couple things so I could test in isolation

stuck bay Jan 27, 2020, 8:12 PM

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hm, thats really weird then. on my picture as you couldve seen the amplitude is getting bigger and thinner each time it reaches the 0 point

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I reset time to 0f on Start(), because this is a bullet instantiation

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does it matter somehow?

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@glacial jolt can I see the settings of your rigidbody in inspector? That might be an issue

glacial jolt Jan 27, 2020, 8:43 PM

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I deleted the scene, but it was default, except with gravity disabled

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@stuck bay

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try just updated the transform's position directly, will show you if the issue is w/ the rigidbody or the equation

stuck bay Jan 27, 2020, 8:46 PM

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but doesnt moveposition nullify the velocity?

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oh wait you meant actually to change transform.position

glacial jolt Jan 27, 2020, 8:49 PM

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yeah

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remove the rb entirely

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just to see what the issue is

weary wind Jan 27, 2020, 11:47 PM

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Hello physics people. I have some questions. I have this beautiful shopper and his shopping cart. (Fig1 https://i.imgur.com/Vjt1jYo.png) I'm moving him around my level with addforce - so he needs a rigidbody, and I want to be able to have items in the cart. Unfortunately, none of the primitives allow for this, and you can't use non-convex mesh colliders with a rigidbody. As a result, I've set up 5 box colliders around my cart on separate game objects for each side and the floor. (Fig2 https://i.imgur.com/uXY6TGo.png). So, with that context, some questions:

If I drop some primitive shapes with rigibodies into my cart, they work as expected, until I start moving around the level. It would be fine if they escape out of the cart through the open top, but they often fall through the walls of the cart itself
The movement when I had a single box collider for both the player and the cart was much better, but now I have a bunch of colliders as child gameobjects, it barely moves around anymore with rb.AddForce.
Essentially I want the cart to move around the level, and to be able to contain items that also move around the level

Imgur

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Really struggling to get Unity physics to behave here so open to any suggestions or better ways of achieving this.

torpid basin Jan 28, 2020, 10:30 AM

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Hey guys. I'm trying to use Fixed Joint to attach objects together. However my objects keep going crazy, shaking violently and then throwing themselves off into the distance. I feel like this would be a common problem for beginners; anyone know where I can find some information on how to correctly use Fixed Joints?

exotic coyote Jan 28, 2020, 12:00 PM

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Greetings how does one go about creating realistic collision in unity,what i have here doesent seem right

📎 Desktop_2020.01.28_-_14.00.15.06.mp4

coral mango Jan 28, 2020, 1:32 PM

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Probably need to place the center of mass somewhere other than the center

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Because unity doesn't calculate it based on anything but the centroid of the rigidbody

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So it is almost always wrong for any asymmetrical shape

whole sequoia Jan 28, 2020, 1:44 PM

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Hello, I'm trying to make an object reflect off the surface of another object, but I want to compute the reflection parameters myself.

I'm trying to find the plane/normal at the collision point between the two objects. Is there a function that can help me do this?

As of now, I have the world space point of collision. Can I use this to calculate the normal vector?

exotic coyote Jan 28, 2020, 2:56 PM

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@coral mango I tried doing that but then it wont move at all

coral mango Jan 28, 2020, 3:08 PM

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Huh.

exotic coyote Jan 28, 2020, 3:53 PM

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Turning becomes harder when i change the center of mass

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Nevermind i fixed it

strange harness Jan 29, 2020, 4:32 AM

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So I'm running into an issue with the Character Controller component. The issue comes, at least in my scenario, when jumping at a wall / side of stairs. The controller will simply "jerk" or "snap" down slightly instead of continuing with the jump. The best thing I've found for how to repeat this behavior is with ProBuilder stairs. Using a simple FPS controller (such as in Brackey's recent video) should yield the same results. Attached is the only resource I've found so far that explains the issue I'm facing (albeit with no leads). (Issue that I'm facing is specifically the first GIF in the thread, where the controller snaps down when moving into a wall or obstacle)
https://forum.unity.com/threads/character-controller-unexpected-step-offset-behaviour.640828/

Wondering if anyone else has encountered this at all, and if there's a way to potentially fix this issue?

Unity Forum

Character Controller - unexpected step offset behaviour

I have a Character Controller component attached to the same Game Object as a script that moves the Character Controller on the XZ plane without...

glacial burrow Jan 29, 2020, 2:40 PM

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Hi. I don't know if it's the good topic to speak about this.

I want to set a balance of this Ringing Bell (2D object). The issue is that when I add Torque to rotate it, it takes at rotation reference point the center of the Sprite (the cross point), however I would like to use the position of the GameObject "Rotation" (the non texture one) as center of the rotation.

📎 Unity_u9QflD8XRV.png

stable shadow Jan 29, 2020, 3:30 PM

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@glacial burrow Have you tried changing the bells center of mass?

glacial burrow Jan 29, 2020, 3:33 PM

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@stable shadow Yes I achieve to do that in 3D but I didn't manage to do it in 2D. And also am not sure to fully understand how Center of Mass works. Because I tried it on just Cube, and it had occur some strange behavior.

ocean horizon Jan 29, 2020, 3:53 PM

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@glacial burrow The method to change it is identical in both 2D and 3D. Just set the "centerOfMass" property.

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It'll rotate around the center of mass.

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Open the "Info" properties, it'll show you the current local/world center-of-mass.

glacial burrow Jan 29, 2020, 3:57 PM

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Where is the "Info" proprieties ? I am new to Unity from 3 weeks ago.

ocean horizon Jan 29, 2020, 3:57 PM

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It's in your image above at the bottom of the Rigidbody2D component in the inspector

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That shows you a bunch of info.

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You can see this on the Rigidbody2D and any 2D collider.

glacial burrow Jan 29, 2020, 3:58 PM

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Oh I see.

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Then, how can I know where I need to put the center of Mass ?
Because I have no tools to see it. I will also try how to use these positions proprely.

ocean horizon Jan 29, 2020, 4:01 PM

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There's no gizmo in the scene to change it.

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It's auto calculated so it rotates around the center of mass of the colliders. To change it, you need to set the property: https://docs.unity3d.com/ScriptReference/Rigidbody2D-centerOfMass.html

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As soon as you change it though, the automatic one that is calculated is ignored.

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You can also read the world center of mass with: https://docs.unity3d.com/ScriptReference/Rigidbody2D-worldCenterOfMass.html

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You could create a simple script that lets you edit it.

glacial burrow Jan 29, 2020, 4:07 PM

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Ok. Thank you.

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I will try it.

ocean horizon Jan 29, 2020, 4:19 PM

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Note that you can make it easier for yourself by having the Rigidbody2D on the parent and at start set its center-of-mass to zero. Have your bell as a child with the sprite and collider and just use the Transform to position it where you like. Everything will rotate around the parent Rigidbody2D center-of-mass. If you don't set the center-of-mass to zero then it'll rotate around the child.

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Alternately, you can use a HingeJoint2D and have it rotate around any point in the world you like.

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@surreal wind I have maintain a GitHub repo that demonstrates a bunch of 2D physics features here: https://github.com/MelvMay-Unity/UnityPhysics2D

GitHub

MelvMay-Unity/UnityPhysics2D

Examples of various Unity 2D Physics components and features. - MelvMay-Unity/UnityPhysics2D

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I just added a Rigidbody2D center-of-mass scene because I realised it was missing. Take a look at it for help: https://github.com/MelvMay-Unity/UnityPhysics2D/blob/master/Assets/Scenes/Rigidbody/Rigidbody2D_CenterOfMass.unity

GitHub

MelvMay-Unity/UnityPhysics2D

Examples of various Unity 2D Physics components and features. - MelvMay-Unity/UnityPhysics2D

#

Note that the master branch is Unity 2020 as I always add new stuff with the latest Unity. There are however branches for previous versions but the above scene is only in 2020 for now.

glacial burrow Jan 29, 2020, 4:32 PM

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Oh thanks you. I will take a look at it.

ocean horizon Jan 29, 2020, 4:34 PM

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Np. When you get it up and running you should see something like this: https://gyazo.com/ba7bd5409b527b9b2d34f9ebd5e09a15

Gyazo

▶ Play video

#

You can change the center-of-mass interactively on the Red GO via the CenterOfMass script.

errant gazelle Jan 29, 2020, 7:14 PM

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How can I make a ragdoll stand up? I am using forces to try to keep each body part in his "relax position"

📎 media.io_2020-01-29_20-05-46.mp4

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Is there a guide on this topic?

gaunt fable Jan 29, 2020, 8:18 PM

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Hey Guys! My partner and I are working on a fellowship that combines Engineering and Art by means of collaboration between Engineering students and an established artist. As a result we've been working a lot in the Unity space and while we have some familiarity, it's been mostly a learning process. So my ask is this. We are currently working with motion capture data and training ML models that can emulate mocap information and we can successfully make a humanoid transforms move and emulate / interpolate different mocap animation clips. That being said we are trying to now move to a more physics based emulation using the different transform data by using Configurable Joints. This however has been quite troublesome and difficult as the documentation on Configurable Joints are pretty poor IMO. Does anyone here have any advice or can potentially help us figure out some of this? Would anyone be open to chatting with my team? Would really appreciate any advice or guidance 🙏

weary wind Jan 30, 2020, 3:00 AM

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Hey team, working through some fun physics things! https://forum.unity.com/threads/shopping-cart.817194/#post-5423289 Wondering if any of you have some ideas

Unity Forum

Shopping cart

Hello physics people. I have some questions. I have this beautiful shopper and his shopping cart. (Fig1 https://i.imgur.com/Vjt1jYo.png) I'm moving him...

#

Should I just be rolling my own at this point?

dense sky Jan 30, 2020, 7:39 AM

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Hello how to disable wasd movements but keep velocity when you jump with rigid body?

📎 666555.jpg

glacial burrow Jan 30, 2020, 9:40 AM

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Hello.
First, thanks melv for the HingeJoint2D. It seems to be the best solution for me now.

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📎 Unity_stqMZHEbeR.png

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However. The sprite rotate well around the Anchor point.

📎 Unity_R3mwglrdel.png

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But even if I link the RigidBody to my "Rotation SPrite Point". It doesn't move dynamically around the "Rotation SPrite Point" if I move it during the Play Manually

hollow echo Jan 30, 2020, 9:42 AM

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You should really be in Pivot mode and not Center whenever you're talking about pivot points

glacial burrow Jan 30, 2020, 9:42 AM

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What do you mean ?

hollow echo Jan 30, 2020, 9:42 AM

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it's hard to know what's what when you're in this mode

📎 unknown.png

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Perhaps it's okay with the 2D gizmos 😛

glacial burrow Jan 30, 2020, 9:44 AM

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Oh okay. It doesn't change anything for this screen so, I thinked it wasn't matter. ^^'

hollow echo Jan 30, 2020, 9:45 AM

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When you say move it manually do you mean yanking the transform in the scene view?

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Or do you mean driving the torque via code

glacial burrow Jan 30, 2020, 9:46 AM

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I mean : using the Move Tool in the Scene.

ocean horizon Jan 30, 2020, 9:48 AM

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@glacial burrow It's not clear but I think you're potentially making stuff harder for yourself. Whatever GO is your pivot (Rotation Sprite Point?), I would suggest that be the parent and be the one with the RB and hinge on it. Children can have sprites/colliders on it. This is pretty much how my example project above worked (without the hinge). Let me hierarchy work for you by doing this.

glacial burrow Jan 30, 2020, 10:01 AM

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@ocean horizon It's working !
Just if I move it manually it ... uhm ... going crazy.

📎 Unity_2018.4.13f1_Personal_-_FightingScene.unity_-_Bell_Rotation.mp4

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But I don't think I will need to move it during the scene, so it's okay. =)

hollow echo Jan 30, 2020, 10:02 AM

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You really can't yank things in the scene view and expect it to go okay ;P

glacial burrow Jan 30, 2020, 10:02 AM

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X'D Ok

hollow echo Jan 30, 2020, 10:03 AM

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Physics things want physics input, and dragging a joint away in the scene avoids the physics and puts it in a state where it has to do a lot of unrealistic behaviour to get it back, and game engine physics isn't great at that sort of thing

ocean horizon Jan 30, 2020, 10:05 AM

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Yes, it's not "moving" through space at all. It's teleporting from one position (pose) to another instantly. The physics system just sees stuff disappear from one position and instantly pop up in another. The joints then have to try to deal with this horrible discontinuous situation and then you keep on dragging and it finds it impossible to create a solution for you. This is no different than you setting the Transform position/rotation.

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Use the physics API to move stuff i.e. velocity, forces, MovePosition, MoveRotation.

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Only move stuff when you're authoring outside of play mode.

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If you need to interact with it then you can create an editor only script that can drag stuff etc.

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In the same repo as I posted yesterday you'll find how to do dragging like this: https://youtu.be/4NSKN3L0fvE

YouTube

Melvyn May

Example of Basic Dragging

Mouse Dragging in Repo: https://github.com/MelvMay-Unity/UnityPhysics2D

TargetJoint: https://github.com/MelvMay-Unity/UnityPhysics2D/blob/master/Assets/Scenes/Joints/TargetJoint2D_MouseDrag.unity

▶ Play video

glacial burrow Jan 30, 2020, 10:08 AM

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Oh. I see.

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Thank you very much.

hollow echo Jan 30, 2020, 10:09 AM

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That repo is really nice btw, it's really fresh to have a lot of good examples across the whole spectrum of the systems

ocean horizon Jan 30, 2020, 10:17 AM

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Thanks. It's a personal project I've maintained and I find it a useful way to communicate stuff so I don't need to do my usual verbose explanations. 😉

stuck bay Jan 30, 2020, 11:20 AM

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https://youtu.be/6ZS5JLdjZbg this is my new project, (note: this is just a test of the physics for ideas I have, not a real thing. I'm also using this to test how objects will work.)

YouTube

RainbowDev

PHYS1CS (Test #1)

Introducing PHYS1CS, a physics simulation game! I might make this into a bigger game later but I just wanted to shove this out right now to let people know about it. I have some ideas that I might experiment with later on in development...so stay tuned!

▶ Play video

narrow harness Jan 30, 2020, 8:19 PM

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I need help with this vehicle, or you could say bus. As much as i try, it refuses to go forward, it only goes to the side. Tried changing the scripts, didnt help. I tried everything in my skill which is not much since im a beginner kinda and been trying to fix it for hours and im losing hope. Can anyone help me please? https://cdn.discordapp.com/attachments/492048394890510356/672482016083574786/bus_test.mp4
https://cdn.discordapp.com/attachments/492048394890510356/672493616874258483/unknown.png

▶ Play video

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I tested multiple scripts and none of them are working so im thinking its related to physics but honestly, no idea

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📎 unknown.png

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📎 unknown.png

drifting wind Jan 30, 2020, 9:08 PM

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@narrow harness Could you please post your entire script on somewhere like hastebin?

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Will make it easier to read and should allow everyone to get a better look.

hollow echo Jan 30, 2020, 9:11 PM

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When you select the bus the forward vector points to the left. In your UpdateWheelPose function it sets the rotation to that. I suspect you're just rotating the wheels weirdly.

narrow harness Jan 30, 2020, 9:19 PM

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sure

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@hollow echo well yea, the wheels are turning weird and i know how to stop them but then they dont turn at all

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and the result is the same

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it wont go forward

onyx cypress Jan 31, 2020, 5:29 AM

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Hey everyone :)
This is a bit of a combination of #archived-dots and #⚛️┃physics , but I think this is a better spot.

I am wondering about the following, help on any of them would be greatly appreciated :)
Some info first though: I am currently using PhysX, components, and game objects. I am transitioning an existing project over to Unity Physics / DOTS. My knowledge is enough for me to understand from a high level how things work, but I don't know the fine details of how to get things to work.
Physics Mass

Am I right to assume the transform field of PhysicsMass is the center of mass? And if so, is it safe to set rotation to quaternion.identity?
For the InverseInertia of PhysicsMass, is this simply float3(6, 6, 6) * inverseMass? If so, is 6 a magic number or is it another detail I need to know?
For the AngularExpansionFactor of PhysicsMass, what is this, how can I calculate it, and what does it do?

Physics Simulation

Is simply just having an entity with PhysicsStep enough to get it to be used?
Is there a way to manually handle running a physics update? I have a custom update system (main thread) which needs to run it.

Worlds

What systems need to be in a world in order for physics simulation to work?
Tied to simulation is calling a world update manually something I can do in order to run a physics update?

Interaction

What is the proper way to raycast? And am I able to detect the exact collider in a compound collider that I hit with said raycast?
Are there any helper methods for applying forces? Specifically add force at position (impulse).

Misc

When I am accessing World.DefaultGameObjectInjectionWorld in an existing project, it is null, but in a new project, it is not. Is this a bug when adding DOTS and such to an existing project that was previously in 2019.2, something weird with packages, or otherwise?

Thanks in advance!

untold sand Jan 31, 2020, 7:53 AM

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is jiggle physics in unity?

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something like this: https://twitter.com/CloudyHasAPie/status/1222964340120150016

CloudyWAT (@CloudyHasAPie)

WHOOSH WHOOSH
#BatDR #Bendy #BatIM
#Bendy_and_the_Dark_Revival
#Bendy_and_the_Ink_Machine
#gamedev https://t.co/lh8ccqFdzl

▶ Play video

mighty sluice Jan 31, 2020, 11:20 AM

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working on a muscle thingy

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https://imgur.com/a/b6Npemf

Imgur

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uses articulations and custom force applications

untold sand Jan 31, 2020, 8:56 PM

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what muscle is that?

onyx cypress Jan 31, 2020, 10:25 PM

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Still searching for the answers to these questions, any help is greatly appreciated :)

https://discordapp.com/channels/489222168727519232/497874196274348032/672674730389667863

lapis plaza Jan 31, 2020, 11:08 PM

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@onyx cypress see https://docs.unity3d.com/Packages/com.unity.physics@latest and https://github.com/Unity-Technologies/EntityComponentSystemSamples/tree/master/UnityPhysicsSamples

GitHub

Unity-Technologies/EntityComponentSystemSamples

Contribute to Unity-Technologies/EntityComponentSystemSamples development by creating an account on GitHub.

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I mean they do show or describe many thing you listed there

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especially the manual is good read

onyx cypress Jan 31, 2020, 11:19 PM

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The parts about PhysicsMass, PhysicsSimulation, Worlds, and Misc I have found little to no information on using those sources. Considering I am doing this all in code, instead of using the authoring components, it is making it much more difficult to find information. I am trying to do this without having to use those since I want to have full control of everything, considering that I actually need that control. In the case of Physics mass, I would leave it alone, but I have a custom mass system in place, so I need to calculate everything. For Simulation, I need to be able to directly control when and how simulation is done. For Worlds, I need to be able to create 1-3 worlds on the client from scratch. (Local world visualization, local world simulation, server simulation)

For Misc, it seems that it is an issue that I can't find any information on.

For interaction, it seems the RaycastCar example has the information I am looking for.

Kind of why I asked here, since those resources haven't exactly gotten me too far, unless I missed something while digging through it.

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The manual especially hasn't been of much help, especially because of the whole setting up from scratch and all in code part. It is all done doing authoring components, which just is hiding everything in massive files which aren't really commented, making it very hard to tell how it actually works.

lapis plaza Jan 31, 2020, 11:23 PM

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https://docs.unity3d.com/Packages/com.unity.physics@0.2/manual/getting_started.html#control-over-the-physics-step

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I'm not going to go over each one where they are mentioned tho

onyx cypress Jan 31, 2020, 11:24 PM

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Literally an authoring component...

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I want to know how it actually works, how I can set this thing up on my own.

lapis plaza Jan 31, 2020, 11:24 PM

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so open the DOTS scripts for it 🙂

onyx cypress Jan 31, 2020, 11:25 PM

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...

lapis plaza Jan 31, 2020, 11:25 PM

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also you don't need to add that manually

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only if you need to alter it

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look, I'm not trying to be a smartass here, it's just at this stage, they haven't explained all dots bits as these things keep evolving a lot. if you go dots now, you have to be willing to dig deep down that rabbit hole :/

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as for raycasts / queries, that same manual has sample snippets for it too

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basically your source of information are

that manual
unity physics samples (altho they mainly use this from monobehavours)
actual Unity Physics source code
DOTS physics forum

onyx cypress Jan 31, 2020, 11:28 PM

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Do I just need to have an entity with PhysicsStep on it in my world? Are default values used if one doesn't exist? How does it handle multiple, does it use the first one? How does it work.

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Going through DLL files and uncommented code to figure that out isn't exactly why I am building a game in Unity.

lapis plaza Jan 31, 2020, 11:30 PM

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Unity only gives support for the authoring component setup atm, so if you want to do something different and learn how it's setup, see what these built-in components do

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but I really don't recommend going to Unity Physics at all at this stage unless you really want to figure out most things the hard way

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you have to handcraft a lot atm

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like the whole fixedupdate/interpolation which doesn't exist on the base package

onyx cypress Jan 31, 2020, 11:35 PM

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I would stick with PhysX if it wasn't complete garbage for what I am trying to do, hence why I am here. I need compound colliders, more control over physics, actually damn deterministic physics, performance increases, all of that stuff.

I quite honestly don't care if I need to build things myself, I am just trying to figure out the basics so I can do that. I am just trying to find something, anything, which actually has some information on this crap, since it seems like a black market secret.

Sorry if I am coming across as rude, I am just pissed off since I can't just find the information I need to get this to work.

lapis plaza Jan 31, 2020, 11:38 PM

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do note that unity physics doesn't have cache so it could be even slower than built-in physics on your open world scenario

naive remnant Jan 31, 2020, 11:38 PM

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but have you looked at Physics code and examples? I think everything is there, there is only 3 main systems and 3 authoring components 🤔

lapis plaza Jan 31, 2020, 11:38 PM

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havok physics could help there tho

onyx cypress Jan 31, 2020, 11:42 PM

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Performance wise it is collider count that is killing me, compound colliders should solve this issue since they are treated more like 1 big collider than 500 separate ones which need to be updated independently.

My world is simple in ways, the terrain is just basic Unity terrain. The problem is that you drive vehicles which are fully customizable, and are entirely physics based.

The code examples are based around the authoring components, and using those as a means to interact with everything. Considering that I am trying to have decent amounts of control over this system, it is difficult to get anything relating to how it actually works. The code that comes with the package is entirely undocumented, and is a mess. It is almost like trying to figure out what the hell is going on in an obfuscated DLL.

naive remnant Jan 31, 2020, 11:43 PM

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but it is not in dll it is in c# code🤔

onyx cypress Jan 31, 2020, 11:43 PM

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It is almost like trying to figure out what the hell is going on in an obfuscated DLL.

lapis plaza Jan 31, 2020, 11:43 PM

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authoring components are just helpers for setting the things on ECS side, they really are there to help you

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I dunno why you wouldn't use them if you need to use this today

onyx cypress Jan 31, 2020, 11:44 PM

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Try and create a compound collider using the authoring components, it straight up isn't possible.

lapis plaza Jan 31, 2020, 11:44 PM

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what?

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you just stuff the extra colliders as child GO's

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done

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just have authoring component on the parent

onyx cypress Jan 31, 2020, 11:45 PM

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My vehicles are generated at runtime, they aren't prefabs.

lapis plaza Jan 31, 2020, 11:45 PM

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ah, well, then you have to do it the hard way

onyx cypress Jan 31, 2020, 11:45 PM

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facepalm

lapis plaza Jan 31, 2020, 11:46 PM

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which means you open those authoring components source code and figure out how to do it on code at runtime

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and then after DOTS updates, be prepared to redo that work

onyx cypress Jan 31, 2020, 11:46 PM

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Ah, yes. The source code. https://hastebin.com/ehiqenizup.m

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The 1k lines of code which I need to now document myself to figure out what the hell is actually happening

lapis plaza Jan 31, 2020, 11:46 PM

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well, you want to do this

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😄

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it's not a finished system, DOTS is nowhere near finished

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so you'll get half baked solutions that change all the time and don't have official docs

hexed horizon Jan 31, 2020, 11:48 PM

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I am kinda bummed that Unity Physics seems content to leave all physics caching/sleeping optimizations to havok, which has a signifcant per seat cost. Seems like a middle ground should have been possible, at least as an opt in for scenerios where u dont need network replay for that entity.

lapis plaza Jan 31, 2020, 11:48 PM

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Unity Physics doesn't even have sleeping

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it computes everything again each time you step it

onyx cypress Jan 31, 2020, 11:48 PM

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Would it kill them to comment the damn code though?

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Havok is technically a 3rd party solution, so shrug

lapis plaza Jan 31, 2020, 11:49 PM

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I dunno, to me that code is quite human readable

hexed horizon Jan 31, 2020, 11:49 PM

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Olento understood, my question tho is was that hard line a good design choice.

lapis plaza Jan 31, 2020, 11:49 PM

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try reading physx source 😄

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or most physics engines for that matter

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they kept Unity Physics codebase relatively simple by design

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also, you wouldn't read 1k line classes just one row after another. Use IDE, navigate to the functions / classes through it so you can follow the code paths

hexed horizon Jan 31, 2020, 11:51 PM

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I am just concerned that the "default unitty physics" will greatly limit the types of games that can use it.. moving a lot of games to havok.

lapis plaza Jan 31, 2020, 11:52 PM

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current state of Havok plugin isn't going to make that fast 😄

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also I feel that many dislike physx for all wrong reasons

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most physics engines have similar basic simulations

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some give you more means to fix things manually

hexed horizon Jan 31, 2020, 11:52 PM

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well, given that physx wont support dots we are between a rock and a hard place here.... lol

lapis plaza Jan 31, 2020, 11:53 PM

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sure, my main grief is that Unity can't expose physx contact modifications for us

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if it did, I'd not even look at DOTS physics atm

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on c++ side, it's super simple to use that physx API

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I implemented and wrapped that physx feat on ue4 in one or two days

hexed horizon Jan 31, 2020, 11:54 PM

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if someone is starting a new game today where performance, world size, or scalability is a primary concern they would be insane not to start with dots, which for many games is going to push them into Havok.

lapis plaza Jan 31, 2020, 11:55 PM

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I'm sure Havok will be a good alternative in the future

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right now it's quite broken but it's super early too

hexed horizon Jan 31, 2020, 11:55 PM

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no doubt, havok IS a good physics engine, no doubt. However its going to be pricy

lapis plaza Jan 31, 2020, 11:55 PM

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it's free for Unity Personal/Plus and ~20 bucks month/seat on pro

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depending on your physics needs and team size, that's not that bad

hexed horizon Jan 31, 2020, 11:56 PM

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also, from my understanding the big problem with Havok is u will have no network replay, which is a bit of a deadend for open world games where u want to have predictable fast paced combat, with anything but fairly basic projectiles (e.g. hit scan).

onyx cypress Jan 31, 2020, 11:58 PM

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Considering I know a game which has used both Unity Physics, and is now transitioning to Havok, they are building a deterministic, networkable simulation of much greater scale and complexity than me, or most games for that matter. It is called GameCraft for those interested.

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So I would say network replay isn't going to be much of a problem.

hexed horizon Jan 31, 2020, 11:59 PM

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well its not that simple tho. There are different kinds of network problems.

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If I shoot a homing projectile that accelerates from a particular position at a target that is also accelreating away, I need to not only be able to hit that target, but make it looks good from the clients perspective.

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and not only for the target that shoot it, or the target that was hit, but for all others within view as well, and in many cases the non-homing version can be more of a problem as at least the homing ones can do some tricks on the client side to guess.

onyx cypress Feb 1, 2020, 12:02 AM

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That is more of a problem for the person working on that feature, not the physics engine.

In my case, my entire simulation is based around resim. Simulate the client ahead of the server, try and figure out where everything should be, and if the client was wrong, put them back on track and get back ahead of the server.

hexed horizon Feb 1, 2020, 12:03 AM

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Unity Physics Network Replay is designed specifically to solve the above problem.

onyx cypress Feb 1, 2020, 12:03 AM

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I do all of that on my own though, even in PhysX.

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I basically built an Overwatch / Rocket League like setup, at least for multiplayer, from scratch. Considering how much I am doing, ya, I am rolling my own setup for that.

hexed horizon Feb 1, 2020, 12:06 AM

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Hmm its not clear to me how great of a solution that would be in the dots/havok case... seems like u would be keeping entities awake and constantly shuttling data between various subsystems?

onyx cypress Feb 1, 2020, 12:10 AM

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Here is a general breakdown of how it works:

A message is received for the newest state the server has simulated
The game's current state is set to that state, which is all ID based. All of the entities that are needed can be found by grabbing everything which has, in my case, a Creation component
Run the normal simulation X times, where X is the amount of frames back you went to set that state

The game has things like time dilation to increase or decrease simulation rate to deal with networking and stuff, but it is pretty simple.

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You aren't really shuffling much data around, and systems don't really need to tell each other about what is happening. Simulation runs as normal every frame, with extra simulation being ran when needed, which doesn't talk to anything except the creation components, perhaps sending a network message out.

Setting the game state is pretty simple, considering we are talking like 1-16 entities here.

hexed horizon Feb 1, 2020, 12:13 AM

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but in dots a lot of the interesting entity states have been atomized, so to simulate them back with their entiteis u are going to lose much of the performance u were trying to gain with dots?

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well its not just the players, its the npc entities u are intereacting with as well. It would be one thing if it was a simple FPS player vs player game and if you have destructiable env then u must consider that as well, even tho its not moving the player and proejctiles are in unpredictable ways.

onyx cypress Feb 1, 2020, 12:15 AM

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I don't have NPCs, I don't have shops, I don't have anything like that. This isn't some open world adventure game, this is basically a 3rd person FPS with a really customizable character which has some complex physics.

hexed horizon Feb 1, 2020, 12:15 AM

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k, which is fair. My goals are obviously a bit different 🙂

onyx cypress Feb 1, 2020, 12:17 AM

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I have an entire setup which handles everything outside of Unity, outside of DOTs, ECS, everything. Most of my code is already doing ECS practices, and is doing pretty well on its own. Hell, the physics engine raycasts are taking longer than the rest of my code combined. I am not using Unity ECS for the advantages it brings, I am using Unity ECS so I can use Unity Physics, which should be a solution for the problem I am solving.

thick widget Feb 1, 2020, 12:34 AM

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Is there any way to make "one-way collisions" in Unity?
I don't mean platforms.
What I mean is having object A push aside object B, without object B pushing object A

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I'm working in 2D

mighty sluice Feb 1, 2020, 4:09 AM

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@thick widget just get the force of the impact (impulse i think?) while the colllision is happening, and apply the inverse of it to the body you want to be in god mode

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@untold sand it's a 2 degree of freedom ball joint style, but prototype

untold sand Feb 1, 2020, 4:11 AM

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A what?

onyx cypress Feb 1, 2020, 4:19 AM

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@thick widget You can use the Layer Collision Matrix, which you can find in Project Settings -> Physics 2D -> Scroll down

It allows certain objects to interact with others. This should allow you to have certain objects which don't interact with others, but others can interact with it.

thick widget Feb 1, 2020, 5:16 AM

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@onyx cypress I know about the Layer Collision Matrix, but that can't toggle specific directions to my knowledge. For example, you can't turn off A ➡️ B or B ➡️ A. I don't think that would even be possible since collisions aren't dealt with like that I don't think

onyx cypress Feb 1, 2020, 5:17 AM

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It is a Matrix, so you get to decide what X can interact with, and you can specify (separately), what Y can interact with.

So it should be possible.

thick widget Feb 1, 2020, 5:18 AM

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@onyx cypress See?

📎 collision_matrix.png

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I can't do Bullet > Tank or Tank > Bullet specifically

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The matrix doesn't care about that

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I want object A to affect object B's velocity etc in a collision but not the other way around

onyx cypress Feb 1, 2020, 5:19 AM

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Well right now your bullet doesn't interact with Tank or Bullet.

thick widget Feb 1, 2020, 5:20 AM

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I know.

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Nevermind, I'll probably just go with a script

onyx cypress Feb 1, 2020, 5:21 AM

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Actually your right, you can't specify one way collisions there...

thick widget Feb 1, 2020, 5:22 AM

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Yeah... I don't think Unity even registers that kind of data on a collision event

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I'll try @mighty sluice's suggestion and see if that works

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Thanks for your help though! I really appreciate it

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Sorry that I wasn't more clear 😝

onyx cypress Feb 1, 2020, 5:23 AM

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👍
Let me know how it goes! Interested to hear what your final solution will be.

thick widget Feb 1, 2020, 5:24 AM

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I will!

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@onyx cypress For some context, what I want to do is make it when the tank crashes into crates the tank pushes the crates aside, but the crates don't affect the tank's rigidbody in any way during the collision

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Maybe there's an easier way to do this that I'm overlooking 😅

onyx cypress Feb 1, 2020, 5:27 AM

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Well.. Could make the tank really heavy and the boxes really light, although it might not work in your setup.

thick widget Feb 1, 2020, 5:28 AM

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Wait a sec

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My tank's rigidbody is currently set up as kinematic

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So would any of this matter?

onyx cypress Feb 1, 2020, 5:31 AM

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📎 unknown.png

thick widget Feb 1, 2020, 5:31 AM

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Because the thing is that occasionally the collisions affect the rigidbody despite the fact that it is kinematic

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I probably should do some more testing

ocean horizon Feb 1, 2020, 9:54 AM

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@thick widget As you already hinted at, the reason you can't do directional collisions is because they don't exist. It's like arguing who walked into who when two people don't see each other then hit. A contact is when two colliders meet, they can either meet or they can't. To say A can't hit B but B can hit A doesn't really make sense. Maybe I'm misunderstanding what you want though but thought this important to point out.

pallid pawn Feb 1, 2020, 5:28 PM

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in my 2d unity game my collision script is not working, can anyone help?

stuck musk Feb 2, 2020, 4:21 AM

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I'm attempting to make a rope out of 2d objects strung together and running into an issue where they overcome the limiter and go further anyway the further it goes down the rope.

#

📎 unknown.png

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📎 unknown.png

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Any idea? When a single box is alone it doesn't go past the angular limits, but when stringing them together I figured it would be additively 3+3+3+3+3 angles for a total swing of something like 15 degrees in both directions for 5 links

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I'm assuming it has something to do with exactly how I attach the anchors but I'm having trouble finding a configuration that works.

ocean horizon Feb 2, 2020, 10:38 AM

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Only things that come to mind are to be careful that you're not linking bodies with high mass ratios (mass 1 connected to a mass 500 for instance). All bodies should be moved with forces, don't modify the transform. You can turn up the solver iterations.

#

It's not clear if you're only describing the angle limits or the bodies separating. One common thing to do is to add a DistanceJoint2D from the start to the end of the "rope" with its "MaxDistanceOnly" checked.

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For an example of this, you can load-up this scene in my GitHub examples project. It also uses angle limits too: https://github.com/MelvMay-Unity/UnityPhysics2D/blob/master/Assets/Scenes/Joints/DistanceJoint2D_MaxDistanceOnly_Chain.unity

GitHub

MelvMay-Unity/UnityPhysics2D

Examples of various Unity 2D Physics components and features. - MelvMay-Unity/UnityPhysics2D

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(Note that the "master" branch is the current 2020.1 alpha but there are other branches for earlier versions of Unity)

mighty sluice Feb 2, 2020, 11:49 AM

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📎 notaphallus3.gif

#

anyone know of existing muscle systems similar to this one?

stuck musk Feb 2, 2020, 3:55 PM

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Their masses were all 1, and I used a distance joint to attach the platform at the bottom to the rope. After turning the collision of the "rope" boxes to trigger, it bent only as far as I had set it to and worked as intended, however there was a consistent +2 degrees to whatever I set the limiter to which is still unsolved. Even with a single rotating object with a rotation of 0. Upon moving it with a 3 and -3 limiter it would go 5 to -5, and this was consistent regardless of the limiter. It would always be + - 2 higher angle than intended.

#

The previous tests were all done using collision with the player character which also has only 1 mass. I'm not modifying their transform directly. Though I'll keep that in mind when scripting the platforms to swing by updating their velocity. Thanks melv

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Are you suggesting to use a DistanceJoint2D on every link in the rope to the top?

ocean horizon Feb 2, 2020, 4:00 PM

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Are you suggesting to use a DistanceJoint2D on every link in the rope to the top?
No, one for the whole length as in the scene above.

stuck musk Feb 2, 2020, 4:03 PM

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I'm relatively new so sorry I may not be understanding. In this picture, what object to what object would have a distancejoint added?

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📎 unknown.png

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It's 5 boxes with 3 degrees of rotation each

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and the platform, and the above anchor

ocean horizon Feb 2, 2020, 4:03 PM

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I cannot be more clear than the explanations and an example scene above that you can load.up

stuck musk Feb 2, 2020, 4:04 PM

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I'll try it out, haven't tried 3D before.

ocean horizon Feb 2, 2020, 4:04 PM

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3D?

stuck musk Feb 2, 2020, 4:04 PM

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oh my bad, thought chris' picture was your own

ocean horizon Feb 2, 2020, 4:05 PM

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No, my GitHub project that demonstrates a lot of 2D physics features including all the joints and their settings

stuck musk Feb 2, 2020, 4:05 PM

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I'm downloading it now, thanks for your time.

ocean horizon Feb 2, 2020, 4:06 PM

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You should see this: https://youtu.be/EH9nj3zcfFQ

YouTube

Melvyn May

Rope/Chain Stability Project

A simple example of using a DistanceJoint2D with MaxDistanceOnly checked to ensure that chains of bodies connected together do not separate.

https://github.com/MelvMay-Unity/UnityPhysics2D

Scene: DistanceJoint2D_MaxDistanceOnly_Chain

▶ Play video

stuck musk Feb 2, 2020, 4:07 PM

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perfect

stuck bay Feb 2, 2020, 8:00 PM

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It's a long shot but is there some obscure resource eli5ing arcade plane physics for games? I'm tired of trying to figure out how to fake torque from NASA's info about aerodynamics equations and all Github repos with plane physics are either winging it with random equations or half applied real ones.

stuck bay Feb 2, 2020, 8:25 PM

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...aand as soon as I posted this I found a book called Physics for Game Developers. Man I looove the rubber ducky effect.

fiery lion Feb 3, 2020, 8:19 PM

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Is this place a good place to ask heavy math questions even though they may not specifically be considered physics?

autumn jetty Feb 3, 2020, 8:57 PM

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Anyone know if the only way to get rigidbody index for an entity is throught the physicsWorld extension function?

glacial jolt Feb 4, 2020, 12:55 AM

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@fiery lion it's prolly the most fitting channel for it

fiery lion Feb 4, 2020, 1:10 AM

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Now I gotta wait until I’m home to be able to ask though 😆 trying to copy/paste or even look at code from mobile is a bit difficult

stuck bay Feb 4, 2020, 7:51 AM

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does exists an method to using Physics.Raycast and Physics.OverlapSphere as Jobs?

autumn jetty Feb 4, 2020, 8:32 AM

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@stuck bay As in that you can use it in jobs if referring of using the DOTS Physics - yes.

stuck bay Feb 4, 2020, 8:49 AM

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so, how? can you take code sample?

lapis plaza Feb 4, 2020, 8:53 AM

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this is getting silly

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you crosspost to different channels and now in #archived-dots people respond to you about physx jobifying and in here about dots jobifying

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(would be better to keep the discussion on one place)

autumn jetty Feb 4, 2020, 9:17 AM

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@stuck bay You can check the physics sample within the ECS sample, you use it from PhysicsWorld which you can get from BuildPhysicsWorld which is a system. https://docs.unity3d.com/Packages/com.unity.physics@0.0/api/Unity.Physics.PhysicsWorld.html

prime flower Feb 4, 2020, 5:52 PM

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Anyone have any advice on Maximum Allowed Timestep settings? I have a networked game that runs on a fixed physics timestep and very often physics states are rolled back and resimulated on the Client. This results in about 20 calls to Physics.Simulate in a single tick.

Should I set Maximum Allowed Timestep to a very low value since I can be confident that my network updates will fix any desync that happens anyways?

lapis plaza Feb 4, 2020, 6:04 PM

#

@prime flower if you do manual physics.simulate's, that value doesn't limit them afaik in any way. that value is mainly there to limit how often FixedUpdate can run in case you run it on low end cpu and it's sole purpose is to prevent the cpu from getting starved (if the cpu can't keep up with physics and fixedupdate keeps chugging more updates for it, it'll starve itself, entering the spiral of doom)

#

so if you set that max allowed timestep to say 0.1, the client will stop running additional fixedupdate loops once framerate drops to 10fps

prime flower Feb 4, 2020, 6:06 PM

#

@lapis plaza okay well then maybe it makes even more sense for me to use after that explanation. I have a Game.cs script that all my game logic flows through. Game.FixedUpdate() runs the main game loop that receives network input, processes it, does the rollback and corrections, increments the tick number, and repeats

#

And my goal is that Game.FixedUpdate runs as consistent as possible regardless of performance

tough valley Feb 4, 2020, 8:42 PM

#

Hi! I recently switched to Blender (and Im no rigger anyway), and I'm wondering about mechanical rigs is it better to rig my assets in Unity with the differents joints it offers or am I good doing it in Blender ? Everything will be imported, all my contraints etc ? Also the goal after that is to have my pieces under physics

modest frigate Feb 4, 2020, 9:38 PM

#

Hi i'm new to Unity and I created one of my first games, the racing game. I tried to add a ramp that goes up but it didn't have car collision so I just went through it. After some time I fixed it and added collision(a pink ramp thing) but my car would just slide off instead of riding on the ramp. Anyone knows how to fix it? If you know please DM me.

onyx cypress Feb 5, 2020, 1:36 AM

#

Hey everyone :)
I am still trying to figure out Unity Physics, and stumbled into 3 things I am hoping I can get some help with:

Is there a way to prevent a physics object from rotating due to physics interactions? Don't exactly want my player rolling around when I try and move them XD
What is angular expansion factor? And how would I calculate it? Considering this relates to physics mass, and I am manually calculating the center of mass, mass, ect. for a game mechanic, it would be nice to know how to get this value, or at least understand what it actually is doing.
What systems are required to get Unity Physics up and running in a world? I am creating some worlds from scratch and need to figure out what is required to get it up and running.

Thanks in advance!

#

@prime flower I build a custom update loop on top of a very fast FixedUpdate for this, since I wanted to convert my game to a more frame based one.

So my FixedUpdate is running at about 200hz, and my custom update loop, which runs on top of it, can run 50 / 100hz nicely. It use DateTime (marks last frame time) and a double to keep track of the time that elapsed, and time which still needs to be simulated. Combined it allows me to guarantee the game is running at that frames rate, so long as performance is not a problem. It however will enter a death spiral if not managed properly, since it tries to always run the amount of frames that need to be ran.

The version I am using in my game: https://hastebin.com/ayabuyazaj.cs
I have another which is used for network simulation, which dilates the amount of frames which typically would be simulated, while otherwise acting the same.

hexed horizon Feb 5, 2020, 4:04 AM

#

Looking for any infromation on how to rig up Unity Physics + DOTs to dynmaically assign and spin up multiple physics instances (as dynamic entiteis enter their range) in a grid like pattern. Rather than origin shifting I want to expore the option of building large worlds with good floating point percision by transitioning entities between physics instances. Obviously ill have some challenges integrating this with the 32bit render, but ill worry about that later =).

onyx cypress Feb 5, 2020, 4:33 AM

#

You are going to be looking at treating the world like an MMO, having multiple regions, switching between them, transitioning, and other such things. So looking up how MMOs handle switching between different zones might be a good place to start to get the general idea of what you will be working on @hexed horizon

hexed horizon Feb 5, 2020, 4:34 AM

#

I am hoping for seamless transitioning.

#

my understanding is unity physics added this feature recently, to be able to spawn multiples any info on this? ideally I would not just say spawn 100 at start.

pine stirrup Feb 5, 2020, 6:39 AM

#

Hey I'm wondering how can I make an object like that in which red things are pivot and green things are just stick

📎 sketch-1580841281709.png

flint glade Feb 5, 2020, 8:32 AM

#

Hey guys, using Blender for modelling and wanted to ask if the physics are imported from Blender into Unity or they're made in Unity?

tough valley Feb 5, 2020, 2:52 PM

#

@flint glade unity

flint glade Feb 5, 2020, 2:52 PM

#

ok thanks

ocean horizon Feb 5, 2020, 4:22 PM

#

@pine stirrup The following test scene might help you. Look in the description for repo/scene details: https://youtu.be/t8B5gYslpIM

YouTube

Melvyn May

Basic Softbody Test.

A basic example of a softbody. In this case using hinges but you can also use DistanceJoint2D to produce a softer joint although you may find that you require more of them.

Also demonstrating the use of break force.

Repo: https://github.com/MelvMay-Unity/UnityPhysics2D/t...

▶ Play video

pine stirrup Feb 5, 2020, 4:26 PM

#

Thx

#

It's something like that but with stick linking the balls and letting the stick rotating around the balls

#

Idk if I'm clear or not x)

ocean horizon Feb 5, 2020, 4:31 PM

#

The stick is just rendering, they don't physically link the balls so you just need to dynamically render them at the positions between the pivots. I took the fact that you posted in the physics group to mean you're more interested in the physics of connecting them. You can use hinge joints or distance joints (although you'll need more distance joints but they'd give you more control over how soft).

#

the position would be the mid-point of both pivots and the angle would be easy to calculate.

#

(or draw the lines if you have access to a vector drawing asset)

pine stirrup Feb 5, 2020, 4:33 PM

#

Oh ok

ocean horizon Feb 5, 2020, 4:34 PM

#

If you try the demo scene I did, I had rotational limits on each HingeJoint2D but if I turn them off then they all rotate around each other and it essentially collapses.

#

I assume you want it like this: https://gyazo.com/7ed8eb787066c1fc2ddb01218b15c572

Gyazo

▶ Play video

pine stirrup Feb 5, 2020, 7:33 PM

#

@ocean horizon yes that was exactly what I wanted GWloopyGok

#

So I just have to download your scene with GitHub to see how exactly you did that?

ocean horizon Feb 5, 2020, 7:55 PM

#

Yes, it's all there and free to use for whatever you wish although the scene on there doesn't have lines drawn although I can add that if you like but TBH, all I did was add a test script to draw a line from one pivot transform position to the connected one.

#

If you have any questions then just ping me.

rain marten Feb 6, 2020, 1:47 AM

#

guys , for platformer game, charactercontroller or rigidbody?

#

for gamename1 i dont think i will be using forces and gravity for levels, like push or pull, etc

#

so i believe i am okay with Character Controller?

lapis plaza Feb 6, 2020, 1:48 AM

#

my vote would always go for custom char controller

#

not meaning anything that's based on built-in char controller

rain marten Feb 6, 2020, 1:49 AM

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im flipping a little with player movement and rigid bodys xD

lapis plaza Feb 6, 2020, 1:49 AM

#

issue with rigidbodies is that you are not in control

rain marten Feb 6, 2020, 1:49 AM

#

right

#

at some point is interesting

mighty sluice Feb 6, 2020, 7:49 AM

#

Anyone know why this is happening and how to avoid it? Iam merely altering the positions and rotations of each segment in these worms (resetting them to a starting pose and position)

📎 splosions.gif

#

I am zeroing out the velocity and angular velocity when i do so, but the segments just love to explode for one or two frames when i do so

#

something is causing the speed or velocity or center of mass to become fubard (NaN)

#

should i be making them kinematic while I reset their position and rotation?

mighty sluice Feb 6, 2020, 8:07 AM

#

there are joints on these segments so possibly they are involved

lapis plaza Feb 6, 2020, 4:35 PM

#

just added to 2020.1.0a22: ```md

Physics: Added: Expose ArticulationBody.jointPosition, ArticulationBody.jointVelocity, ArticulationBody.jointAcceleration and ArticulationBody.jointForce to access the corresponding values in reduced coordinate space.```

viral ginkgo Feb 6, 2020, 5:05 PM

#

@mighty sluice you probably shouldn't need to alter positions

#

if all segments are parented to eachother

#

just set the position of root segment
and then reset all rotations of segments
if all segments are parented to next segment

pulsar oracle Feb 6, 2020, 8:12 PM

#

Hey there!
I would like to build a good and realistic bus physics, including a slide suspension to move the bus up or down to let passengers get onto. Also, a gear transmition to change its torque depending on its velocity.

Anyone know tutorials or references that I can study and build it? Actually I already did it, but it's too simple! Soon I'll send a video to show my work. Thank you so much

📎 Captura_de_Tela_72.png

lapis plaza Feb 6, 2020, 8:17 PM

#

same vehicle basics apply to a bus, just like in a car

acoustic lynx Feb 6, 2020, 10:11 PM

#

is there any way to read the velocity of a Rigidbody right after using AddForce()?

#

it seems it's not updated instantly (engine probably waiting for physics update)

viral ginkgo Feb 6, 2020, 10:20 PM

#

@acoustic lynx

📎 unknown.png

acoustic lynx Feb 6, 2020, 10:20 PM

#

i guess that means it's updated one physics frame later

viral ginkgo Feb 6, 2020, 10:21 PM

#

yes

acoustic lynx Feb 6, 2020, 10:21 PM

#

any workaround there?

viral ginkgo Feb 6, 2020, 10:21 PM

#

velocity +=

acoustic lynx Feb 6, 2020, 10:21 PM

#

+= what?

viral ginkgo Feb 6, 2020, 10:21 PM

#

your force

acoustic lynx Feb 6, 2020, 10:21 PM

#

wow xD

viral ginkgo Feb 6, 2020, 10:21 PM

#

its still acceleration

acoustic lynx Feb 6, 2020, 10:21 PM

#

hmmm

#

another person told me the same

#

but i somehow don't get it

viral ginkgo Feb 6, 2020, 10:22 PM

#

acceleration is change in speed

stark bolt Feb 6, 2020, 10:22 PM

#

lol you moved here

acoustic lynx Feb 6, 2020, 10:22 PM

#

velocity unit is meter / second, isn't it?

viral ginkgo Feb 6, 2020, 10:22 PM

#

both that and addfoce does that

acoustic lynx Feb 6, 2020, 10:22 PM

#

while force is newton

#

from a physical point of view you can't just add them up. that's what i mean

stark bolt Feb 6, 2020, 10:22 PM

#

acceleration is just adding to the velocity

viral ginkgo Feb 6, 2020, 10:22 PM

#

yes accelarion is meter/second per second

acoustic lynx Feb 6, 2020, 10:23 PM

#

so you guys

viral ginkgo Feb 6, 2020, 10:23 PM

#

force causes acceleration

stark bolt Feb 6, 2020, 10:23 PM

#

also I got a D in highschool physics but I feel like this was well covered

acoustic lynx Feb 6, 2020, 10:23 PM

#

are talking of adding acceleration * fixed_delta_t (don't know what the time variable is)

#

?

viral ginkgo Feb 6, 2020, 10:23 PM

#

F=m.a
a = F/m

stark bolt Feb 6, 2020, 10:23 PM

#

~~acceleration == force * mass * timedelta~~ bargos got it

viral ginkgo Feb 6, 2020, 10:24 PM

#

if you did addforce(F)
now you do
rb.velocity += F/rb.mass

#

time delta is inside the F

acoustic lynx Feb 6, 2020, 10:24 PM

#

acceleration = force/mass *

#

😛

#

well thanks now it makes sense

viral ginkgo Feb 6, 2020, 10:25 PM

#

i made that meme now, what do you think

acoustic lynx Feb 6, 2020, 10:25 PM

#

oh yours?

viral ginkgo Feb 6, 2020, 10:25 PM

#

just did it now

acoustic lynx Feb 6, 2020, 10:25 PM

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it fits well

viral ginkgo Feb 6, 2020, 10:25 PM

#

i had a nasty bug related to that
that i solved yesterday

#

wanting to make that meme since

acoustic lynx Feb 6, 2020, 10:26 PM

#

i'm not happy that there's no way to compute the current velocity with the functions of engine tbh

viral ginkgo Feb 6, 2020, 10:27 PM

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you know what i think that is for @acoustic lynx

#

If velocity was changed immidently as you apply force, your simulation would depend on the execution order

acoustic lynx Feb 6, 2020, 10:27 PM

#

true

stark bolt Feb 6, 2020, 10:27 PM

#

also you need to ask the physics sim if theres a wall

#

so ya gotta wait for it

acoustic lynx Feb 6, 2020, 10:29 PM

#

Tront I would guess you can just apply forces immediately and manage the collision afterwards - from the physics engine perspective

stark bolt Feb 6, 2020, 10:29 PM

#

in a perfect world we'd have pre-and post physics hooks

#

most game engines do

#

not sure why unity said nope

viral ginkgo Feb 6, 2020, 10:30 PM

#

you read the state of the scene from previous frame when calculating what happens on a given rigidbody

#

because next scene is not complete yet

acoustic lynx Feb 6, 2020, 10:30 PM

#

perhaps for performance reasons

viral ginkgo Feb 6, 2020, 10:30 PM

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because order of execution shouldn't matter

acoustic lynx Feb 6, 2020, 10:31 PM

#

(to what you and Tront said)

#

so back to my problem. I definitely have to compute the current velocity myself?

viral ginkgo Feb 6, 2020, 10:32 PM

#

just pass in some value you think will fit

#

just like what you did with addforce

acoustic lynx Feb 6, 2020, 10:32 PM

#

the time delta i need is

#

fixedDeltaTime?

#

just out of interest: is unity doing it the same way internally? - applying the last fixedDeltaTime for physics computation?

#

(I would be happy if the function I make for this was consistent with the overall physics system :P)

stark bolt Feb 6, 2020, 10:35 PM

#

fixedDeltaTime, and deltaTime checked in FixedUpdate return the same value

#

by default its 50hz

#

0.02

#

configurable in the Time panel in project settings

acoustic lynx Feb 6, 2020, 10:36 PM

#

wait

#

I'm not entirely sure if that is right (I also said some bs up there)

#

fixedDeltaTime The interval in seconds at which physics and other fixed frame rate updates (like MonoBehaviour's FixedUpdate) are performed.

stark bolt Feb 6, 2020, 10:38 PM

#

📎 unknown.png

#

yeah Id recommend changing it

acoustic lynx Feb 6, 2020, 10:38 PM

#

thx i just opened it

#

but what i wonder rn is

#

will Update and FixedUpdate always run at the same speed?

stark bolt Feb 6, 2020, 10:39 PM

#

whoa my messsage got deleted lol

#

no they dont

#

Update runs at the maxfps of the device if vsync is disabled

#

FixedUpdate runs at a fixed rate

acoustic lynx Feb 6, 2020, 10:40 PM

#

what about that variable fixedDeltaTime

#

they say in the docs (like i cited above) "interval in seconds at which the physics [..] updates"

#

so this applies for FixedUpdate()? but not for Update()?

stark bolt Feb 6, 2020, 10:45 PM

#

yes exactly

acoustic lynx Feb 6, 2020, 10:46 PM

#

👍

#

also thanks @viral ginkgo

viral ginkgo Feb 6, 2020, 10:50 PM

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@acoustic lynx if you are doing this in update, Time.deltaTime
if doing this in fixedUpdate Time.fixedDeltaTime

acoustic lynx Feb 6, 2020, 10:50 PM

#

alright

viral ginkgo Feb 6, 2020, 10:50 PM

#

This wont make you game any smoother though

#

if you are moving with acceleration this doesn't matter at all visually

#

but you want your game to be framerate independent

#

and frametimes change

#

even in fixed update

#

its not completely fixed

acoustic lynx Feb 6, 2020, 10:51 PM

#

yeah so i wonder why fixedDeltaTime seems to be a constant then

viral ginkgo Feb 6, 2020, 10:51 PM

#

fixed delta time isnt always 0.02

stark bolt Feb 6, 2020, 10:51 PM

#

yes it is

#

o.O

#

go print it

#

even when you adjust timescale it doesnt change

viral ginkgo Feb 6, 2020, 10:51 PM

#

when your game lags, unity will space out fixed frames
it will increase so unity may catch up

stark bolt Feb 6, 2020, 10:52 PM

#

thats the entire point of FixedUpdate

acoustic lynx Feb 6, 2020, 10:52 PM

#

wow

#

that's a lot stuff the docs don't seem to mention

stark bolt Feb 6, 2020, 10:52 PM

#

no it just slows things down it doesnt increase it thats what the max allowed timestep is for

viral ginkgo Feb 6, 2020, 10:52 PM

#

@acoustic lynx

📎 unknown.png

acoustic lynx Feb 6, 2020, 10:53 PM

#

(assuming they mention it somewhere but when i look those variables up it seems misleading)

viral ginkgo Feb 6, 2020, 10:53 PM

#

by default settings, it may take 0.3333 at max to complete a fixed update

#

but you can complety lock it if you put 0.2 there

acoustic lynx Feb 6, 2020, 10:53 PM

#

📎 unknown.png

stark bolt Feb 6, 2020, 10:53 PM

#

Maximum Allowed Timestep

Fixed time stepping ensures stable physics simulation. However it can cause negative impact on performance if game is heavy on physics and is already running slow or occasionally dips to low frame rate. Longer the frame takes to process - more fixed update steps will have to be executed for the next frame. This results in performance degradation. To prevent such scenario Unity iOS introduced Maximum Allowed Timestep which ensures that physics calculations will not run longer than specified threshold.

If frame takes longer to process than time specified in Maximum Allowed Timestep, then physics will "pretend" that frame took only Maximum Allowed Timestep seconds. In other words if frame rate drops below some threshold, then rigid bodies will slow down a bit allowing CPU to catch up.

Maximum Allowed Timestep affects both physics calculation and FixedUpdate() events.

Maximum Allowed Timestep is specified in seconds as Fixed Timestep. Therefore setting 0.1 will make physics and FixedUpdate() events to slow down, if frame rate dips below 1 / 0.1 = 10 frames per second.

#

zzzzzz

#

basically unity will drop the framerate independence

#

if you're lagging so bad it cant catch up

#

it does NOT change the freakin timestep

acoustic lynx Feb 6, 2020, 10:55 PM

#

hm k. having a maximum allowed timestamp makes sense

viral ginkgo Feb 6, 2020, 10:56 PM

#

It is okay to not use these time deltas in fixedupdate though

acoustic lynx Feb 6, 2020, 10:56 PM

#

that avoids things glitching through walls etc

viral ginkgo Feb 6, 2020, 10:56 PM

#

it doesnt change much

acoustic lynx Feb 6, 2020, 10:56 PM

#

well

#

as i said earlier. I'd like to keep my physics computations consistent with unity's physics

#

if unity computes the new velocity with 0.333 s and I do with 0.02 cause i put it in the code with that number instead of using the Time.fixedDeltaTime varibale my calculations will be wrong

viral ginkgo Feb 6, 2020, 10:58 PM

#

oh wait wait sorry 0.333 is alot

acoustic lynx Feb 6, 2020, 10:58 PM

#

ya xD

viral ginkgo Feb 6, 2020, 10:58 PM

#

i though it was 0.0333

#

use the deltatime

acoustic lynx Feb 6, 2020, 10:58 PM

#

honestly i just noticed rn too haha

#

(but i already would have compained at 0.0333)

viral ginkgo Feb 6, 2020, 10:58 PM

#

but
maybe you want the forces to stop if your game lags like that

acoustic lynx Feb 6, 2020, 10:58 PM

#

to be clear the fixedDeltaTime?

viral ginkgo Feb 6, 2020, 10:59 PM

#

how long it took to complete last fixed update

acoustic lynx Feb 6, 2020, 10:59 PM

#

i mean you make games so they run on average computers ig, but you still want people with bad computers to be able to play it

#

so fixedDeltaTime seems to be like deltaTime just for the FixedUpdate() instead of Update()

stark bolt Feb 6, 2020, 11:00 PM

#

yes

viral ginkgo Feb 6, 2020, 11:00 PM

#

yeah

acoustic lynx Feb 6, 2020, 11:01 PM

#

I kinda wished the docs made that relation more clear, nvm though

viral ginkgo Feb 6, 2020, 11:02 PM

#

i never had any issues with weird forces because of this stuff

#

and i didnt use deltatimes often

stark bolt Feb 6, 2020, 11:02 PM

#

yeah in fixedupdate you dont actually ever need to apply the time because its always assumed that the time is unchanging between fixed frames

viral ginkgo Feb 6, 2020, 11:03 PM

#

most important place you need this deltatime is

in void Update()
when you are dealing with camera

stark bolt Feb 6, 2020, 11:03 PM

#

^ complete trooth

#

camera is the one thing where I need deltatime for my slerpy lerpy movement

#

smoothdeltatime

#

because I dont like hiccups

viral ginkgo Feb 6, 2020, 11:03 PM

#

or if you move your character in update but thats not a very good idea

stark bolt Feb 6, 2020, 11:03 PM

#

🤢

acoustic lynx Feb 6, 2020, 11:04 PM

#

i have something for you guys

#

📎 unknown.png

#

📎 unknown.png

#

note the difference 😛

viral ginkgo Feb 6, 2020, 11:04 PM

#

works both ways
but second will make you look cooler

acoustic lynx Feb 6, 2020, 11:04 PM

#

(just a parody of when both of you said something like: add the force to the mass :P)

stark bolt Feb 6, 2020, 11:04 PM

#

lmao

acoustic lynx Feb 6, 2020, 11:05 PM

#

na first won't work. i'm pretty sure 🤔

viral ginkgo Feb 6, 2020, 11:05 PM

#

mass is just a constant number

stark bolt Feb 6, 2020, 11:05 PM

#

yeah so is fixeddeltatime

#

so its basically the same

#

just a different multiplier

acoustic lynx Feb 6, 2020, 11:05 PM

#

the direction will be right. but the magnitude is wrong

stark bolt Feb 6, 2020, 11:05 PM

#

📎 unknown.png

#

dont forget we have forcemodes

#

so addforce can be applied in 4 different ways

viral ginkgo Feb 6, 2020, 11:06 PM

#

just adjust the magnitude and you'll be fine

acoustic lynx Feb 6, 2020, 11:06 PM

#

yeah thanks. sadly i couldn't solve that problem i came here with with those. but they're pretty helpful

viral ginkgo Feb 6, 2020, 11:07 PM

#

they are all the same as addforce but force is multiplied by deltatime/mass or not for each

acoustic lynx Feb 6, 2020, 11:07 PM

#

with forcemodes "adding a force works" if that's what you mean

viral ginkgo Feb 6, 2020, 11:08 PM

#

they are the same force but multiplied with different constant numbers

acoustic lynx Feb 6, 2020, 11:08 PM

#

yeah

stark bolt Feb 6, 2020, 11:08 PM

#

all I know is that my favorite is impulse

acoustic lynx Feb 6, 2020, 11:08 PM

#

📎 unknown.png

#

still don't see a good solution from unity for just reading the resulting velocity, because of that problem you mentioned

viral ginkgo Feb 6, 2020, 11:09 PM

#

you cant get resulting velocity because it is not calculated yet

acoustic lynx Feb 6, 2020, 11:09 PM

#

I think it gets even more complicated when working with torque

viral ginkgo Feb 6, 2020, 11:10 PM

#

maybe another object is going to touch that object until the end of the frame

acoustic lynx Feb 6, 2020, 11:10 PM

#

i would be fine with a function like: GetPredictedVelocity() : )

viral ginkgo Feb 6, 2020, 11:10 PM

#

what do you need

acoustic lynx Feb 6, 2020, 11:10 PM

#

na i'm good

#

📎 unknown.png

viral ginkgo Feb 6, 2020, 11:11 PM

#

say it in more higher level if you still need a workaround

stark bolt Feb 6, 2020, 11:11 PM

#

thats a good predictor

#

plus gravity 😛

#

throws a wrench

viral ginkgo Feb 6, 2020, 11:12 PM

#

in general you don't want functions that are doing these at the same time:

changing something in your scene, code, class variables or anything
returning a value

@acoustic lynx

#

Read that in "clean code"

acoustic lynx Feb 6, 2020, 11:13 PM

#

perhaps i will

#

My thoughts on this right now are: If a developer wants this kinda functions he probably should just write them themselves

#

for example a function like i mentioned: GetPredictedVelocity() - would it include gravity or not? might get pretty specific at one point

stark bolt Feb 6, 2020, 11:16 PM

#

yeah I mean thats always what it ends up being

#

if you want something good

#

you gotta do it yourself

acoustic lynx Feb 6, 2020, 11:16 PM

#

: )

viral ginkgo Feb 6, 2020, 11:17 PM

#

why do you want such a function though i'm wondering

stark bolt Feb 6, 2020, 11:17 PM

#

golf

acoustic lynx Feb 6, 2020, 11:17 PM

#

probably there are better solutions for this

stark bolt Feb 6, 2020, 11:17 PM

#

I mean idk his reasoning but I used to draw a predicted shot

#

thats why I needed it

acoustic lynx Feb 6, 2020, 11:18 PM

#

I wanted to decelerate my Rigidbody and at the point the resulting velocity goes in opposite direction of the velocity before the AddForce()

#

I would knew I would have to stop the Rigidbody (So in a nutshell: slowing down and then not overshooting)

#

therefore my original question about comparing velocities - before and after AddForce

#

I'm open for alternative solutions

viral ginkgo Feb 6, 2020, 11:21 PM

#

that function doesn't predict the velocity without altering it though

acoustic lynx Feb 6, 2020, 11:21 PM

#

AddForce()?

viral ginkgo Feb 6, 2020, 11:21 PM

#

ComputeResultingVelocity()

acoustic lynx Feb 6, 2020, 11:22 PM

#

wow

#

I seriously must have had a stroke when writing it

#

thanks

viral ginkgo Feb 6, 2020, 11:22 PM

#

just remove += with +

#

Thats why i said you are doing the two things you shouldn't be doing at the same time

#

Always will lead to bugs

acoustic lynx Feb 6, 2020, 11:25 PM

#

honestly the main problem was probably i was writing code and chatting at the same time 😉

#

I check out clean code though

#

this one? https://github.com/sampaiodias/unity-clean-code

GitHub

sampaiodias/unity-clean-code

Quick guide to help Unity developers create more robust, maintainable, and cleaner C# code. - sampaiodias/unity-clean-code

viral ginkgo Feb 6, 2020, 11:27 PM

#

Clean Code: A Handbook of Agile Software Craftsmanship

#

not unity related

#

I haven't read all of it

acoustic lynx Feb 6, 2020, 11:27 PM

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oh

viral ginkgo Feb 6, 2020, 11:27 PM

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but it's quite good

stark bolt Feb 6, 2020, 11:28 PM

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thats the bob martin book right?

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I found some other ones to be a bit easier to digest

viral ginkgo Feb 6, 2020, 11:28 PM

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it talks about importance in naming,
why small functions are good (even less then 5 lines)
that thing i said about 2 things at the same time
and other such stuff
at least in the beginning

acoustic lynx Feb 6, 2020, 11:29 PM

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Tront feel free to link some here

viral ginkgo Feb 6, 2020, 11:29 PM

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i haven't went far into hard to digest parts

stark bolt Feb 6, 2020, 11:30 PM

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well I didnt finish the book I switched from clean code to uhhh

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head first programming patterns

acoustic lynx Feb 6, 2020, 11:30 PM

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for digesting you need to do some work related

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that's why it's good to have a book that also serves for looking up thinks quickly

stark bolt Feb 6, 2020, 11:30 PM

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i found the head first book way easier but I'll give clean code another try

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everyone recommends it which is why I found it

viral ginkgo Feb 6, 2020, 11:31 PM

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ah, this book i've seen before

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better read it sometime

acoustic lynx Feb 6, 2020, 11:31 PM

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perhaps i'll check out the clean code one

viral ginkgo Feb 6, 2020, 11:31 PM

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@stark bolt don't take my recommendation on it though, i didn't read 1/4th of it probably

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design patterns would be good to learn

stark bolt Feb 6, 2020, 11:33 PM

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yeah there are a lot of em

left sierra Feb 7, 2020, 1:12 AM

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Ok, I'm really going crazy here^^ Is there any way to achieve deterministic 2d physics across different machines with the normal system, packages, external github projects whatever to use in a deterministic lockstep multiplayer game?

viral ginkgo Feb 7, 2020, 2:09 AM

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@left sierra
this could be what you are looking for

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https://github.com/SnpM/LockstepFramework

GitHub

SnpM/LockstepFramework

Framework for lockstep RTS, TD, and MOBA games. Contribute to SnpM/LockstepFramework development by creating an account on GitHub.

left sierra Feb 7, 2020, 2:16 AM

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Ah I just found the RTS engine version of that one in my google search. But this one still feels really "heavy". It has a lot of extra stuff around it, not really a physics engine but rather a full framework for a lockstep game.

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I'll take a look at it and see if i can simplify it, thanks B.A.R.G.O.S

pulsar oracle Feb 7, 2020, 3:08 AM

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Thanks for the help!!! 😶

drowsy idol Feb 7, 2020, 3:49 AM

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If I apply force to a rigidbody, will the parent object also recieve the force?

autumn jetty Feb 7, 2020, 9:11 AM

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@drowsy idol I've yet to meet a system that supports parented rigidbodies

viral ginkgo Feb 7, 2020, 11:07 AM

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@autumn jetty if you want to parent rigidbodies
only have rigidbody on root

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and you can have colliders in children

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those colliders in the children will be a part of the parents rigidbody

ocean horizon Feb 7, 2020, 11:16 AM

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@drowsy idol Kinematic bodies as children is the only hierarchy of bodies you really ever set-up. In that case they have special logic to defer to the relative position of the parent. but that's a non-physical link. It's just a hard link that the transform system imposes. For physical links you obviously use joint constraints if you want to constrain them i.e. add a force to a body and when it moves, it's physically constrained by the other. Don't use the Transform system (which isn't part of the physics solver) to drive physics like that.

mighty sluice Feb 7, 2020, 11:17 AM

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regular joints are best used without parent-child relationships between rigidbodies. 'Articulation joints' (available in unity 2020 a17) depend entirely on the hierarchy relationships though

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for joints, each "joint" requires its own rigidbody, and articulations simulate mass with a built in setting

silk sky Feb 7, 2020, 12:32 PM

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Hi im making somekind of circular gravity with 2 object, one represent a planet, and the other "the player" . The thing is that the script is continously being executed, and the player keeps quakening. the only way to fix in live, is to freeze the z axis when the player collides the planet... any idea of how implement this?