⚛️┃physics

[dusty stone]

Locked to z plane with z rotation

The hinge joint is rotating in all axis : ( i dont get it

Im trying to build a free deathmatch dungeoun

4player

[haughty scaffold]

Hi! I'm currently making a VR tennis game, and I'm having trouble with the racket physics. All i need is for the racket to always be tied to the player's hand. One way i did it was just by setting transform.position, which didn't work because the position wasn't being controlled by Physics.
(the racket went through the ball). Same goes for parenting the racket. Using Rigidbody.MovePosition makes the collision work, but its wayyy too hard of a collision. A simple hit will send the ball FLYING, same with using OVR Grabbable/Grabber. How do I get around this?

Like, is there a way for me to reduce the scale of the collision force for Rigidbody.MovePosition?

[dusty stone]

Setting the chain.z velocity to 0 seams good enough for government work

[dusty stone]

No not satified, not good enough

[mighty sluice]

@dusty stone still here?

i can explain how to use the configurable joint

Squirl?

@dusty stone i can explain the config joint to you but i need a few details about your desired use

depending on what you need, you must make sure that the joint anchor is oriented and placed correctly, that you're locking the right axes of linear and angular motion, and a few other settings

[dusty stone]

Nice

Im trying to make a 3d chain swing on the z axis only but use a 3d rigidbody

[mighty sluice]

i got my cirtual muscle controller worked out i think

[mighty sluice]

is the game meant to be 2d?

in other words, are you already constraining all rigidbodies on the Z?

[dusty stone]

Its 3d and 3d

Not all not all the time

I made two seperate links for 2d and 3d

[mighty sluice]

depending on how your physics is meant to operate, constraining the physics might lead to unrealistic immovable objects or cause strange feedback issues

this usually happens when an unconstrained rigidbody meets a constrained one in the wrong way

[dusty stone]

Mm hmm

[mighty sluice]

so if during this swinging stuff the player body is Z constrained, you can probably constrain the rope with no issues

im assuming the rope dangles from a high point?

[dusty stone]

Yes

[mighty sluice]

ah yea now i see it

[dusty stone]

Sometimes very high

[mighty sluice]

do you want it to just be a dead chain, that players can hang from?

[dusty stone]

Jump swing chain

[mighty sluice]

(swinging on chains/vines like george of the jungle isn't exactly physics realistic lol)

[dusty stone]

I know

Im suspending reality

[mighty sluice]

i actually made something like this in VR. one sec

https://i.imgur.com/5TywdWT.mp4

it basically works like i assume you want (except in 3d)

[dusty stone]

Yes exactly like that lo c ked to the z plane

[mighty sluice]

so aside from the chain itself, i am creating a joint at runtime to link the player to the chain

it's an OnCollision() thing

this way you dont have to fuck with the rigidbodies too much

[dusty stone]

Nice

[mighty sluice]

so assuming you get the chain working, you can do the grab feature with a runtime joint

it's tricky to initialize them in code, but you will quickly get used to it

[dusty stone]

Thats what i need is the chain working : )

The hinge joint wasnt acting like a hinge

[mighty sluice]

the hinge joint is hot garbage

never use it

all the joints except configurable are hot garbage actually

[dusty stone]

Ahh

[mighty sluice]

maybe the fixed joint might pass some tests

ok so about making a chain

[dusty stone]

: D

[mighty sluice]

first step is literally to make a chain of joints. the way that works well is to have one rigidbody be your anchor, and then the next link of the chain connects to it

let me make a quick drawing

[dusty stone]

I did that

I made the top and it builds to height

Set number of links with a gizmo

So i can visualize it in the room prefab variants

Links em together

[mighty sluice]

my guess is that you're not correctly setting up the joint axes or anchor points

why hasnt it been working?

[dusty stone]

It rotates in the x axis and y and i just want z rotation

[dusty stone]

The chain swings off the z plane 0

[mighty sluice]

you need to lock the axes you aren't using

that will do it through the joint, but you can also use rigidbody constraints

[dusty stone]

They werent playing nice with the hinge

[mighty sluice]

free will probably work for your angular motion in the z

[dusty stone]

Kewl ok got it

[mighty sluice]

and just lock everything else

if you constrain via rigidbody, then all the angulars set to free is fine

[dusty stone]

What makes them link together ill try it hold on

[mighty sluice]

actually..... yea... just make sure your rope doesn't twist

at the top

connectedBody

that is a reference to the rigidbody that the joint links to

[dusty stone]

Yes

[mighty sluice]

without that reference, the joint will pretend to have some kinematic anchor

[dusty stone]

Its still rotating in all axis

X y and z

[mighty sluice]

do you mean twisting?

[dusty stone]

I checked in chanell box while playing

Twisting and double bending just swinging around

[mighty sluice]

your joints aren't sharing the same rotation then

you are probably offsetting them when you build it, right?

to make the chain look like a chain?

[dusty stone]

Yes

[mighty sluice]

the joint axes probably are referring to different directions individually, so as a whole the chain can move in those dimensions

[dusty stone]

Hmm interesting

[mighty sluice]

so, the solution here is to change the nature of your chain-link prefab

this is something i ALWAYS do with rigidbodies

have an empty game object as the parent, with 1:1 scale, and give that parent the rigidbody

put whatever collider and renderers in as children, and reshape them there

this way, instead of offsetting the rigidbody to make your chain, you can just offset the renderer/collider

[dusty stone]

Yes i did that but the colliders are with the rigid body

[mighty sluice]

and since the joint will be on the parent/rigidbody, it can be given a sane starting rotation

colliders dont need to be with the rigidbody

they can be in children

[dusty stone]

Oh what

[mighty sluice]

it will still calculate the same center of mass, inertia, etc...

you will still get collision events in the rigidbody for all the child colliders

etc...

[dusty stone]

2d and 3d

[mighty sluice]

the major benefit of doing this is that you dont need to rescale your rigidbody

[dusty stone]

Could i use 3d colliders with to chain

Using children

Wd chain

[mighty sluice]

yes, 3d colliders will work for your 2d chain concept

and that is as it should be if you are working with 3d colldiers already

[dusty stone]

My rigid body is one to one, nice thanks ill give that a try i think youve solved it thank you anything else

[mighty sluice]

yes there is one more thing

[dusty stone]

I dont understand why all joints are acting like rope swings no matter how i cuntrain them

[mighty sluice]

you can constrain the Z motion of the rigidbody to make the chain stay on the Z plane. You might still need to deal with the chain links twisting, but that is a joint thing

it's because your chain building function makes them that way by offsetting their rotation

so each joint has an offset Z axis

you need them to all have the same origin rotation

[dusty stone]

Ill try it with configurable ahh kewl

[mighty sluice]

or else you need to approach it from rigidbody constraints

you can make your hinge version work

just use child colliders

make sure all the links have the same rotation

[dusty stone]

Thanks buddy yeay

[mighty sluice]

the rigidbody must have teh same rotation

the child collider and renderer can be offset

[dusty stone]

Itll be tricky to move the pivot right

[mighty sluice]

what do you mean?

you can offset the placement of the child collider

that way you can have the default pivot be exactly where you want it

[dusty stone]

Uh im preciceley positioning the chains and their pivots

Im confused but i think i can figure it out you want me to move the mesh and colliders but not rigid body right

I was shifting the links rigidbodies down the y axis

[mighty sluice]

yes. The position of the parent /w rigidbody should be your joint pivot point

that way you can spawn it in right at the place where you want the pivot to happen,

and the child collider offset will take care of the rest

i think your chain building func will just need to rotate the child collider instead of rotating the parent

[dusty stone]

Its not even rotating yet

The links are even

[mighty sluice]

they look rotated

[dusty stone]

I know i have two versions thats an old pic

I will try child collider technique thank you very much

[mighty sluice]

welcome

[dusty stone]

@mighty sluice its as i feared the boxcolleder doesnet push the 2d hinge, ill have to try configurable joint again

[mighty sluice]

@dusty stone why not try the 3d hinge?

[dusty stone]

@mighty sluice i did it swings in all axis for some reason : (

[mighty sluice]

constrain the rigidbody's of all the chain links

constrain the Z motion

or whatever is your depth

@dusty stone use the edit angular limits gizmo so you can visualize the joint rotation axis

it's the top button

select all the chain links and press that button

[dusty stone]

Ok i will i have all settings locked except for angular z hmm ok ill try limits too

[dusty stone]

The first configurable joint werks perfectly but the next one in the chain rotates in all axis

[mighty sluice]

how is that possible if you constrain the z motion?

check the freeze position option for Z

[timid dove]

Probably want to constrain x and y rotation too

[dusty stone]

@timid dove the hinge is not abiding by its set limits after the first link and freeze rotation x and or freeze position z on rigidbody makes the hinge malfunction

[haughty scaffold]

(bump)

[uneven shore]

anyone? any thoughts/ideas .. ?

[dusty stone]

@mighty sluice. I subtracted the joint position.z from room.z 0 and applied it to the velocity, and set the angular x velocity to zero and rotatation x and y to zero, a viola flawless 2d simulation of 3d chain omg its beautiful : D thanks for the help

[spare gust]

Hello I bought an asset off Unity and I have no idea how to turn it into a physical object. Now, with a 3D cube I know how to add gravity and make it a rigid body ect. Currently I'm working on a VR project and I've added scripts to cubes to pick them up. However, I have a glass beaker I want the model to have the same shape and what not while being a physical object. I wanna use Nvidia Flex for water physics and fill the beaker with water. I have no idea what I'm doin! halp.

Here is the object

[frigid pier]

Should start with a physics tutorial at least on Unity Learn, not going at it blindly. Dynamic object needs rigidbody and a convex collider.

[spare gust]

Ok great and I can find that on the Unity page?

[frigid pier]

https://learn.unity.com/search?k=["q%3APhysics"]

[torn parcel]

Why would someone use physics2d.circlecastall over a circle collider2d component, when building 2d melee mechanic?

[supple sparrow]

🤔 I'd say the first one allows you to check on-demand ? (only when player/agent punches for example). The latter would be always there and consume computing during the physics simulation step, every frame.

• maybe some other things I don't think about right now

[torn parcel]

so the circlecast is only active for the frame that its called? that's awesome! Attack the componant to follow a sword and draw it the size of the weapon, then animate it during the attack() call and you've got a hyper accurate collider. But I'm guessing it would only cast during the first frame of the animation?

[supple sparrow]

Yeah it will cast the circle from origin, towards direction, along a linear path. and yeah all the way in the frame, it won't lerp between the beginning and ending of your animation, if that's what you wonder about.

attaching a trigger collider to your sword and just animate your sword will work too

and allow non-linear movement

casting shapes helps a lot detecting missed collisions between 2 frames when movement is too fast for the engine

all depends on the complexity of your game and if it's arcade-ish or heavy simulation

you can go as simple as doing a distance check in the middle of the action, and below an attack range threshold you hit, above you missed

[torn parcel]

@supple sparrow you are saving me right now! Would you share your experience with me just for a moment? I am dreaming of this 2d physics arcade style game. It's top-down 2d pvp combat. The goal is to have many, flashy, differentiated abilities, which can interact with the environment, other abilities and players.

Understanding collisions and animations was just the beginning for me, because I wanted to be able to create a sword/shield character but wanted the physics of your placement to be important. The different between a few pixels, or how a sword swipes, being very important.

Last piece: So I started with attaching colliders and creating animations to swing the sword. For spells, I was creating effects and letting them collide as well. I was thinking about attaching effects on gameobjects I will instantiate, to create placable/moveable spells. What's your take on this? Some pointers, or just a piece of advice based on your experience would be amazing!

[supple sparrow]

That's a broad question 🙂 but that's a good start. I would probably start with instantiating GO for effects too, yeah.
Unity's physics can be nerve-racking sometimes, so just go with your ideas and see if that works. Don't forget to stress-test and profile with a lot of gameobjects when you think you get something working.

For instantiating a lot of quick effects as gameobjects, look into object pooling to recycle old ones instead of creating new ones each time (that's an optimisation that can be done later, focus on fun gameplay first)

If your idea does not work, search how others did on that specific topic but whatever you try, have fun along the way and you won't give up

[primal thicket]

I've recently implemented companions in my game (without a NavMesh Agent) and it all works nicely except for one thing.

If I'm colliding (Rigidbodies) with my companion, the player will stop.

I've tried to implement stuff like this:

    private void OnCollisionEnter(Collision collision)
    {
        // how much the character should be knocked back
        var magnitude = 1000;
        // calculate force vector
        var force = transform.position - collision.transform.position;
        // normalize force vector to get direction only and trim magnitude
        force.Normalize();
        myRB.AddForce(force * magnitude);
    }

And it does push my companion away, but not the way I want to. It's pushing the character in the way I'm moving, so that partner still blocks my path. I want it to push my helpmate away/aside, so that it doesn't block the path of my player.

This: https://imgur.com/a/mGcHNXN is what I'm trying to archieve.

I'd prefer to not change anything about the player's rigidbody, since I already adjusted these properties for a good movement.

If anyone has any idea on how to implement this, please let me know.

Thanks in advance!

Rigidbody properties

[dusty stone]

@torn parcel that sounds really fun top down pvp with swords and spellz, i get by with physics alright and design games, so message me if you want to chat 🐌

[muted kernel]

Why are these cubes slightly hovering above the ground? And why is one of them slightly higher than the other? They both have character controllers.

[wide nebula]

Try lowering the Skin Width

[muted kernel]

it seems slightly better, but there is still a height difference. i would be perfectly fine with the hovering as long as they were hovering at the same height

their skin widths are both the same

[wide nebula]

Is everything else the same? Including their transform scales?

[muted kernel]

yes

[timid dove]

I don't see any difference in those screenshots

[muted kernel]

its a difference of about 1 pixel on the screenshots but its very jarring

heres a more zoomed in shot

[wide nebula]

Are you sure it's just not the fact it's not pixel perfect?

[muted kernel]

i played with the positions of the ground and of the boxes and its fixed now

[hot solstice]

Hi guys!
I created code in unity based on C# language and Path Creator plugin(spline).
However, my code doesn't work with the plugin
I need to rewrite the code, or to make it always show the current speed in the variable.
So how do you do that?

My code: https://pastebin.com/FaLuKG0d

Is it possible to somehow adapt this data to the plugin?
I accept all proposals

Thanks in advance!

[timid dove]

Not sure you have explained what you're having trouble with exactly

[stuck bay]

I have made a rigidbody player movement controller and I am experiencing something weird... When I freeze rotation for the rigidbody, the rigidbody seems to experience friction with the surface, which does not happen when I do not freeze rotation. This is happening even though everything has an assigned physicsmaterial with friction set to 0. What is causing this?

nvm... I am stupid

[magic crow]

I'm having an issue a few people seem to have had, but I can't find a solution I like; Rigidbody objects being able to zoom up steep slopes

I'm making a car game, so I want to be able to traverse some slopes, but at the moment, cars can travel up vertical walls

[timid dove]

shouldn't happen unless you're doing some serious direct velocity or position modification

Rigidbodies will generally respect conservation of energy (though definitely not perfectly)

[magic crow]

what I've done is to alter the position of a sphere object and have the rigidbody follow it

transform.position = Vector3.MoveTowards(transform.position, theRB.transform.position, speedInput * Time.deltaTime);

where theRB is the rigidbody of the sphere

the options I've found so far are to set up a raycast (but that means if the car hits something the ray misses, it could shoot into the air) or a sphere cast. but I think that might inhibit the traversal of acceptable slopes

[timid dove]

I'm confused

which object is that code on

that code seems to be moving an object towards a rigidbody

[magic crow]

that code is on the vehicle

[timid dove]

so what is theRB?

[magic crow]

the vehicle is set to follow a sphere rather than be directly controlled

theRB is the sphere the vehicle is following

[timid dove]

oh

ok I mean... the real question is how is your sphere moving then

[magic crow]

adding a force directly to it

[timid dove]

then it's just a matter of how much force you add and in what direction, no?

[magic crow]

I don't know to be honest - this is how the sphere is being moved:

[raven summit]

Hi.
I have small problem with Rigidbodies and hierarchy on the scene.
I have a car with rigidbody, and in this car I have a hood, doors, screws wheels, etc. as children with rigidbody too.
In this car you can take off the wheel and screws, so they own rigidbody and colliders.
I want to make car non-kinematic, but it collides with its own children and car is flying because of these collisions.

I thought I can make simple script where the car detects OnCollisionEnter if a wheel is currently his child, and if is, to set Physics.IgnoreCollision with it.
Is it a good solution?

I don't want to create layers, because it has to be interactable with each other.

[timid dove]

OnCollisionEnter is too late

By that time the collision has happened and any depenetration/collision impulses will have happened too

[raven summit]

Ah, You're right.
So what can I do?

[timid dove]

THere's an experimental API that maybe could help you? https://forum.unity.com/threads/experimental-contacts-modification-api.924809/

But I would say that when you make something a child of the car the child should be kinematic

[raven summit]

It is when is a part of the car and is non-kinematic when you take it.

[timid dove]

Do the parts have to interact with the car when they're removed?

[raven summit]

They have to collide with this car.

[timid dove]

I guess you want it so they collide with the car but only after you've pulled them clear from the car?

[raven summit]

Yes, exactly.

[timid dove]

It's tricky but

you could probably do it with a separate trigger collider inside the car

moving, if you're using the physics engine for it

otherwise no

correct

that is a simple math calculation

[raven summit]

I'm using triggers to pick up items, so every part have colliders and one trigger collider.
If I understand correctly, I would add a trigger to the car that would turn ignoring on and off

But this will collide with picking up items

[timid dove]

yeah you'd have to probably put it in a whole separate layer... it would be quite messy

[raven summit]

I was afraid of using separate layers and wanted to avoid it.
Is there really no ready-made solution in Unity?
I thought that something like this should be because it would be very useful.

[timid dove]

layers are a ready made solution in Unity

but this whole car attach/detach thing is quite a specific use case

[raven summit]

Hm, What if I put a separate object into the car with its own trigger and without rigidbody on a different layer that would ignore picking up objects?
Would that make sense and would be the optimal solution?

[tropic imp]

i have an asset map for some demo game but the tree collider is not working, any way to fix this ?

[sour wadi]

Hey guys! Anyone can help me with a parabola projectile? I'm using a rigidbody and I want to give it the distance, speed and height desired and then have a method to calculate the force needed. After that just use rb.AddForce(force). But how can I do this?

[reef lance]

If you know the desired height and the gravity, you can calculate the y component and the time it takes.
Now that you have the time you can see how fast you need to go in the x/z directions.
You now have all 3 speed components of the force vector, you just need to adjust for object weight.

If this is 2d, then you can ignore z

[wind cipher]

Im trying to do a type of angry birds game, so this is my scene now

But when I press play, the bird place itselfe in a diferent possition...

Can someone help me fix my bird lol

Ok nvm, i got it

[sour wadi]

And how can I make all those calculations? Its 3d

[reef lance]

timeToFall= Math.Sqrt(2 * gravity * height);

Force is an impulse (only happens once) so you only need to worry about speed at first)
x and z speed is based on traveling those distances in 2 * timeToFall (since that is only half of the parabola)
y speed is gravity * timeToFall
Then you multiply this x,y,z vector by the mass of your object and you will have the force needed

[sour wadi]

like this? it is not working properly...

[severe merlin]

hello, could someone tell me why this does this when hitting corner of object. I am using boxcast

[daring bronze]

@severe merlin one if not all of your x,y,z coordinates match that of the object and because your object is assigned a collider your "player" can't go through it, so it's going on top of it.

[magic crow]

hellooo - I have an object following a path using the following:
transform.position = pathCreator.path.GetPointAtDistance(distanceTravelled);
transform.rotation = pathCreator.path.GetPointAtDistance(distanceTravelled);

it works fine, but because it's using transform.position, it's ignoring object collisions. What's the best way to change this so that it can interact with colliders properly?

[severe merlin]

I mean why it is going up and down

[magic crow]

I think rigidbody. is depricated it seems?

[severe merlin]

it is supposed to go on top of the object where hitting

it is coded like that

[daring bronze]

Hmm I'm not sure you'll have to wait for someone else, but it would probably help if you listed each objects component and a snippet of code related to the collision of both objects.

[severe merlin]

if(Physics.BoxCast(wall.GetComponent<Collider>().bounds.center, new Vector3(wall.transform.localScale.x-wall.transform.localScale.x/2, wall.transform.localScale.y, -range), cam.transform.forward, out hit, weaponPos[0].rotation, range)){
   if(hit.collider.name != "Terrain" && !hit.collider.isTrigger){
   weaponPos[0].position = new Vector3(weaponPos[0].position.x,  hit.collider.bounds.max.y+wall.transform.localScale.y/2, weaponPos[0].position.z);
  }
}

here is what changing position of the wall if boxcast hits object. weaponPos[0] is the position where wall is instantiated and also it is parent of wall

And on the video you can first see when it hits on corner of a object it starts going up and down but when hitting flat surface it is working fine

[magic crow]

hmm, I've changed my script to Rigidbody.MovePosition and Rigidbody.MoveRotation, but I'm still not having any luck in getting it to collide with an object

it's running in FixedUpdate, the collider of the object is fine (other things collide with it)

this method shouldn't ignore colliders should it?

[severe merlin]

and rigidbody positions aren't locked and it is not kinematic?

[magic crow]

correct

interpolate, continuous dynamic

I'm totally lost, the script is set to follow a path, which it is doing, and it's interacting properly with the ground

yet it can move through a box collider as if it's not there

[timid dove]

Does it have a collider (the rigidbody object)?

Is the box collider a trigger?

Is either collider a trigger?

[magic crow]

the rigidbody does have a collider, and neither are triggers

I am mystified

[timid dove]

share code?

and screenshots of the object inspectors?

[magic crow]

what's the best method? imgur for the screenshots?

[timid dove]

just paste them into discord

for sharing code use a paste site

[magic crow]

https://paste.ofcode.org/4U7vPvwba6V7TiXcKebJEv

ok, I hope that's enough!

[timid dove]

ok so you're trying to move the sphere on a bezier path

[magic crow]

yeah

[timid dove]

but have it stop at a collider

so it's just going through as if the box wasn't even there?

[magic crow]

yep

[timid dove]

Or is it stopping for a bit and then going through

[magic crow]

it just goes straight through

I thought it would stop and then eventually turn

as far as I understand it, the code just moves it towards the direction of the path, rather than altering it to be in the same position as the path

[terse thicket]

Hey Guys, I have a wand in VR and I am trying to catch the velociy of the wand (to cast a spell) and generate the velocity of the spawn prefab based on the magnitude of the wand movement.

@timid dove 🙂

void FixedUpdate()
    {
        velocity = rb.velocity.magnitude;
    }

I am displaying this velocity magnitude in this inspector and was expecting this to be updated constantly but its not the case.

it's changing but not instantly

[timid dove]

The physics update is not as frequent as your framerate

it's only every 50th of a second by default

[calm plank]

It certainly could be MORE frequent on weak hardware

[severe merlin]

hello, why the wall drops off so quickly.

here is the code

[magic crow]

phew, fixed it - edit > project settings > max depenetration velocity was set to 10

I've upped it to 1000 and that's working as expected now

[terse thicket]

So how would I transfer the velocity to another object then? I need to capture the movement of the wand ( in the meantime I configured a classic addForce to the spell for now but since I am going to create target to aim at, I would like to be able to put them in different depth

[viral ginkgo]

@terse thicket keep track of the position of the tip of the wand

(newpos - oldpos)/deltaTime is your spell shooting velocity

[terse thicket]

So we will not capture anything from the source Rb then? But only the transform?

[timid dove]

You should use the RB. Get the velocity of the tip with https://docs.unity3d.com/ScriptReference/Rigidbody.GetPointVelocity.html

As for transferring it to another object - if it needs to be in Update you will have to interpolate

[terse thicket]

Oh okay I will have a look @timid dove

Thanks

[plucky sierra]

If I have a an object with high bounciness collide with another object with high bounciness on a slope is there any reason the collision event would fire off (tested with debugging and noteworthily plays sound effect) but wouldn't actually cause a bounce to occur? The bounce works fine on other surfaces so long as they aren't sloped.

(This is in 3d physics not 2d)

[distant coyote]

How complex are the respective colliders?

[plucky sierra]

Box and Capsule

capsule landing on top of box

or moving into

The ground is a mesh collider though

[lapis plaza]

gif / video would help

@plucky sierra

[torpid prism]

how to convert rotation to a normal

Quaternion -> Vec3

[hollow echo]

rotation * Vector3.whicheverDirection

[torpid prism]

what is the default

i don't need to rotate a vector but to convert it

[hollow echo]

forward? I dunno, what are you looking for?

It's like asking what's the default side of a cube

[torpid prism]

given a quaternion u can draw an arrow , also given an normal u can draw a plane

[hollow echo]

Given a quaternion you can draw many arrows

[torpid prism]

how to do draw a normal given a quaternion then ?

[hollow echo]

depends what axis you care about

[torpid prism]

no ?

emm ok how do u convert euler to vec3 ?

[hollow echo]

euler angles are already a vector3

and again, they don't have a direction associated with them

[torpid prism]

but its rotational vec3 , i need directional vec3

aka point / normal

[hollow echo]

they don't have a normal.

If your system thinks a normal is the forward vector, then use that

if it thinks it's up, then use that.

[torpid prism]

normal u mean default

normal i mean normal to a plane

[hollow echo]

I mean normal to a plane.

[torpid prism]

how can i get a normal given rotation ?

[hollow echo]

I'm not going to repeat myself

[torpid prism]

lets say default is UP

[hollow echo]

rotation * Vector3.whicheverDirection

[torpid prism]

so rotation * UP ?

[hollow echo]

yes.

[torpid prism]

a bit weird. but ok

thanks , i just don't understand quats i guess

that's what i got and it does seem to work ...

Quaternion YToZ = new Quaternion(0, Mathf.Sqrt(2) / 2f, Mathf.Sqrt(2) / 2f, 0);
var normal = ( Quaternion.LookRotation( p ) * YToZ ) * Vector3.forward; /// times Forward as its the engine's Default AXIS.... ? ? ? 

my confusion is mainly because you still can see all the relative local axis in the editor when rotating a transform

so it sort of retains the information of each axis's "normal" / pointing direction

[hollow echo]

what is that YToZ doing?

[torpid prism]

moving Y to Z

[hollow echo]

seems overcomplicated

[torpid prism]

relative to the rotation space the object in

how would u do it otherwise ?

[hollow echo]

I'm a little confused by what exactly you're doing, you have a direction and you construct a new rotation using it, then you rotate that again, and then convert that back to a direction

[torpid prism]

all i want is a right angle to the axis i have

p is being that axis

the right angle would be another axis

[hollow echo]

I'd just do two cross products

[torpid prism]

how ?

and of what

[hollow echo]

or, one even. Like, what you're doing is already creating a rotation where it's up is aligned to Vector3.up

[torpid prism]

Quaternion.LookRotation( p ) gives rotation based on vector p , then im turning it 90 degrees

later im converting it to vector

[hollow echo]

It gives a rotation based on p and up

[torpid prism]

hmmm

but seems like whatever value of p i feed it , it will give me back a right angle to that value

not sure how to do it otherwise

i get it that quat is a normal + angle combo

[hollow echo]

basically the same as Vector3.Cross(dir, Vector3.up).normalized; is all I'm saying

it'll also have an issue when looking directly up or down afaik

[torpid prism]

just fed the formula above and it looks off

white is the one i quoted above , black is the one u just shared

here are the points for reference

basically what i got using this odd sqrt(2)/2 is the result if you rotate the handles gizmo green arrow towards any point , and the result would be the blue axis

hence why i said 90 degrees rotation

relative to the quaternion

anyhow it's what i needed so thanks @hollow echo

[hollow echo]

Quaternion.LookRotation(dir) * Vector3.up;

should be the same

the YToZ thing is just confusing

[torpid prism]

ok now im confused , its a 1:1 match to the white lines

how is that working

[hollow echo]

because the logic is simple

A * B, A rotates B

[torpid prism]

ah right

[hollow echo]

it's probably easier than cross products, because LookRotation is automatically handling the continuity issue at the poles. Anyway, glad it's working 👍

[torpid prism]

what are continuity issues in a cross product ?

[hollow echo]

a cross of the same directions is invalid

LookRotation takes two inputs, and when it sees that they are the same direction it automatically swaps out the second direction for something else that works

Like if you provide two Vector3.up to it it will swap the second one for a Vector3.right

[torpid prism]

interesting

[woeful cypress]

https://streamable.com/3n7116
i'm trying to push a ball using rigidbody the player collider moves out of position when i do it, is there any way to fix this or recenter the collider to its initial postion!

[timid dove]

You should use Joints for this kind of thing I think

And fake the rolling like they do in the Unity Roll A Ball video

[proud nova]

Don't they use straight up physics to roll the ball?

@woeful cypress Maybe you could keep resetting the player's position throug RB MovePosition, though you need to be careful to not mess with the pushing

Could fake the pushing by applying the force directly on the pushed object and just having the character follow it

[timid dove]

you know what - I'm totally thinking of a different video

[woeful cypress]

Did this for now, until i find a proper solution

used a trigger to toggle constant force

[timid dove]

seems like a good solution to me

[knotty saddle]

https://youtu.be/ozbYSsO8zGc

Hello there! I've got a little physics problem
So i've got an XR project set up with a pistol, some magazines and a few enemies
And i've got this system set up where flicking the wrist "pulls" objects towards you, like in Half Life: Alyx
I've got this equation (screenshot) set up which sets the velocity of the pulled object to a parabola that goes from the targeted object to transform.position (in this case the left hand)
it works, but i've got a problem where pulling an enemy (not intended just for testing) works great, but pulling pistols isn't strong enough and puling magazines is too strong
all rigidbodies have the same settings, mass gravity everything.
also changing the displacement value (pullH) doesnt fix it either

[light sedge]

does someone know by what is this caused?

[reef lance]

Pretty sure you need to multiply the velocity by the objects mass at the end, not gravity

timeUp=sqrt(2 * hUp/gravity)
timeDown=sqrt(2 * hDown/gravity)
velY=gravity * timeUp
velX=distanceX/(timeUp+timeDown)
velZ=distanceZ/(timeUp+timeDown)
force=vector(velX,velY,velZ) * objectMass

[knotty saddle]

that might be it, i'll try that out! @reef lance

[supple sparrow]

If I remember well, Unity puts them as some kind of sleeping mode (or kinematic maybe 🤔 ) so they don't cost as much for the simulation

[wraith junco]

Why can't wheel colliders be used with ignorecollision

my character controller is able to push around my car just by walking into the wheels

[little pier]

can anyone tell me why my player is stuck in the floor?

[mighty mirage]

RIP

[supple sparrow]

Can you provide more info ? how are the collider setup for player and ground, do you use the character controller from unity, do you set Y position yourself, do you spawn him above the ground, is the player origin at center of mass or at the feet, .... ?

Then it would be easier for someone here to help

[magic crow]

can someone tell me how to adjust the rate of acceleration using ForceMode.Acceleration?

[timid dove]

By changing the Vector3 you pass into the function of course

[magic crow]

at the moment, the Vector3 I'm passing in is transform.forward:

theRB.AddForce(transform.forward * speedInput, ForceMode.Acceleration);

I can't find anything in the documentation about which part is supposed to affect the rate though

Yeah, I've just tried breaking down the vector3 into constituent parts, and they all control the vector, never the rate. Are you saying I can pass a function specifically to ForceMode.Acceleration?

No, that's not the case, ForceMode.Accelerate is not a function

[reef lance]

theRB.Acceleration = vector3

[magic crow]

I'm lost here. I thought ForceMode.Accelerate was supposed to add a force to my rigidbody in a way that mimicked acceleration, i.e. increasing over time

but I can't find a way to adjust the rate of acceleration, only the force input

[timid dove]

This is all that ForceMode.Acceleration does:

• Take the Vector3 you passed into it
• Multiply that Vector3 by Time.fixedDeltaTime
• Add the result to rb.velocity

so if you want faster acceleration, you pass in a larger Vector3

If you use ForceMode.Velocity change it does exactly that same thing, except it skips the multiplication by Time.fixedDeltatTime

The definition of "acceleration" is simply "change in velocity"

[magic crow]

Hmm. Essentially, I've tried messing around with the vector3, butall it does is accelerate at the same rate with a lower max speed

What you're describing is how I thought it should work, and that it should just keep adding force to the object, but that doesn't appear to be the case, it looks like it's working as a multiplier with a capped value

[timid dove]

if it's being capped - something else in your code is capping it

try printing out the velocity of your object right before and after the AddForce call

[magic crow]

The input is being capped by me, but I have a debug outputting that to the screen. It never goes above 200, but if I halve it to output 100, it will never reach the same velocity no matter what time

In the same way, the input is linked to the trigger, so if I squeeze halfway, the velocity won't keep increasing past a certain point

[bitter gate]

Hi guys, I have a cube with a rigidbody attached and I try to move it in the direction the camera is facing.
So I have a camera as a child and retrieve the forward direction.
I use that direction in the AddForce method on the rigidbody but my cube is only rotating and not moving in a particular direction

[timid dove]

Do you have drag on your RB?

[timid dove]

show code?

[bitter gate]

public void Update()
{
    if (Input.GetKey(KeyCode.W))
    {
        _rigidbody.AddForce(_cameraTransform.forward, ForceMode.Acceleration);
    }
}

_rigidbody = GetComponent<Rigidbody>();
_cameraTransform = GetComponentInChildren<Transform>();

[magic crow]

I do, I've tried altering it at runtime via the inspector and it doesn't make any discernabke difference

[timid dove]

You shouldn't really do this in Update, It should be in FixedUpdate

but it should still push the object in the correct direction

Do you have any constraints on the Rigidbody?

[bitter gate]

No I dont

the cube keeps just rotating and then falls over

[timid dove]

show a video maybe?

[magic crow]

Could that be friction on the ground object?

In response to Kreide I mean

[timid dove]

GetComponentInChildren<Transform>() is actually just going to give you your own Transform most likely

I think you have the wrong transform reference

instead try ```cs
_cameraTransform = transform.GetChild(0); // If the camera is the 0th child

Or just Camera.main.transform

[bitter gate]

Ok I'll try

Oh it doesnt embed mkv

[timid dove]

Don't worry about it - I'm 95% sure it's your transform being wrong

[bitter gate]

No it still doesnt work

[timid dove]

what did you change to

[bitter gate]

_cameraTransform = transform.GetChild(0);

[timid dove]

is the camera the first child?

[bitter gate]

Its the only child

[timid dove]

ok

Discord embeds mp4s

[bitter gate]

yeah it is using the wrong transform

I printed out the values

[violet shell]

Can enyone help me with collider 2D?

[timid dove]

what issue are you having

[violet shell]

dont working

[timid dove]

Care to elaborate?

[violet shell]

ok

this is player

this is wather (i want to stop player when it touch te water)

@timid dove

[timid dove]

Does the player have a collider?

How are you moving the player?

[violet shell]

1 yes
2 i moving player by changing transform

[timid dove]

1. If you don't have a rigidbody then Unity just considers your colliders as static colliders. No collision will happen between two static colliders

2. If you do add a rigidbody to your player, you should not move it by directly changing the transform

or you will still go through walls

You either need to use Rigidbody or use a raycast-based Character Controller script

[violet shell]

Thank you

[violet shell]

but how can i change position using rigidbody

[timid dove]

You don't.

You set the velocity or add forces, and the Physics engine moves the object for you

[violet shell]

ok

thx

[patent idol]

can we check layer with raycast?

[timid dove]

Check layer, or limit layer?

If you want to limit which layers it hits, use a LayerMask. If you want to check the layer of the thing you hit, there's a layer property on the GameObject

[patent idol]

this is what basically i am trying to do

trying to detect if ray hits a layer

but its not giving any output

[gentle plume]

Why Physics.BoxCast takes only one vector for a ray? Shouldn't the ray be defined by starting point and its direction?

[timid dove]

At first glance this seems fine

[timid dove]

It takes both

https://docs.unity3d.com/ScriptReference/Physics.BoxCast.html

Center, direction, and distance

[gentle plume]

the center is the center of the box not the start of the ray

center Center of the box.

Or I should just move the box relatively the ray... alright then

[patent idol]

does all raycast needs some kind of collider?

[timid dove]

Yes

[timid dove]

There's no ray. You're sweeping the box itself through the scene

[gentle plume]

Got it. Thanks

[hearty hawk]

I'm doing a top-down car controller and I want to use rigidbody to control the accleeration, deceleration, etc.
Is there an easy way to calculate what drag power I need if I want my car to accelerate with an X value, to a top Y speed, and decelerate with a Z value ?

Or should I manually add a speed limit, acceleration and deceleration rate, and don't bother with rigidbody's linear drag ?

[cinder pivot]

can anyone help me figure out why my character is running through these colliders, and how to fix it so they can't? I think I am missing something really stupid.

inspector of one of the colliders

[violet shell]

Wait

You use white unity?

[cinder pivot]

lol

it changes based on the time of day actually

[violet shell]

Ok

X

D

[cinder pivot]

Sooooo

colliders

not colliding

halp

[violet shell]

How are you moving plejer

[cinder pivot]

with a character controller, but the character wasn't moving through similar colliders with identical components

[violet shell]

So

Idk

Sorry 😔

[cinder pivot]

oh hold o

on*

ugh

okay i "fixed it"

he now colliders with them but if he keeps running he teleports through it suddenly rofl

[violet shell]

Ok

[cinder pivot]

sigh

well i fixed it. I don't know why, but the colliders were only working one way

i rotated them around and they work fine

[foggy rapids]

they need to have rigidbodies

[cinder pivot]

nah they don't

thanks though i got it

i set them at walkable layer and my character controller collides with colliders on layer walkable

without need to add rigidbody

[timid dove]

yeah you don't need rigidbody for CC to collide

CC uses raycasts

[patent idol]

hey the code i wrote was for 3d is there a way to write similar code for 2d?

layer check for 2d

[timid dove]

it's similar for 2D except you use Physics2D.Raycast

oh wait sorry

for a moousee click

you would use

[patent idol]

uhm it doesnt take any ray parameters and obviously it has only 4 directions

[patent idol]

yea

[timid dove]

Physics2D.GetRayIntersection

[patent idol]

oh okay

[timid dove]

https://docs.unity3d.com/ScriptReference/Physics2D.GetRayIntersection.html

[patent idol]

thank you 🙂

[patent idol]

this would work directly in if prethesis right

[timid dove]

No

it returns a RaycastHit2D

you have to do like

RaycastHit2D hit = Physics2D.GetRayIntersection(...);
if (hit.collider != null) {
  print("Hit!");
}```

[patent idol]

god finally works man ._. god i was so messed today because of this thanks

[timid dove]

np!

[patent idol]

just one more thing

can i filter out child layer somehow?

its detecting layer 0 right now

which is the whole object's layer

i want to detect child's layer with raycast which is child of that object

[timid dove]

You can filter which layers the raycast hits with a layer mask parameter

[patent idol]

thank you i managed to do it 🙂 thanks for all the help

[cinder pivot]

would this be the right channel to ask for help with creating a hex-shaped grid system for placing 3D hex tiles at run-time?

[night mural]

uhh

when I release the physics on a bunch of rectangles

they skew

when they rotate

instead of rotating normally

[timid dove]

Do you have a bunch of parent/child relationships with non-uniform scaling?

[distant coyote]

Yes.

[steady gazelle]

Does anyone know why this capsule collider rigidbody behaves like this?

I'm advancing per frame in this video

The object has a drag of 15 and I use AddForce to apply a custom gravity

[frigid pier]

Make sure you are applying everything in FixedUpdate and not setting any overriding rigidbody properties directly.

[steady gazelle]

I did set 2 Physics.IgnoreCollisions, so that is probably the culprit?

Because there is something in the way here that is not visible that this rocket should not collide with

[steady gazelle]

Okay, I found out what it was
I was using transform.LookAt to make the rocket always face the direction it's flying in, but forgot to deactivate it after it started drowning in water

[latent plume]

Hey, could anyone look at my simple platformer physics?

They are handwritten, and are mooostly useable, but I have a slight issue where sometimes the player cannot jump

private bool PlaceMeeting(Vector3 position, string tag)
{
    // Get all overlapping colliders
    float x1 = position.x - physicsCollider.bounds.extents.x;
    float y1 = position.y - physicsCollider.bounds.extents.y;
    float x2 = position.x + physicsCollider.bounds.extents.x;
    float y2 = position.y + physicsCollider.bounds.extents.y;
    Vector2 p1 = new Vector2(x1, y1);
    Vector2 p2 = new Vector2(x2, y2);

    // Get overlapping colliders
    Collider2D[] overlappingColliders = Physics2D.OverlapAreaAll(p1,p2);

    // Check if any colliders are relevant
    bool overlap = false;
    foreach (Collider2D overlappingCollider in overlappingColliders)
    {
        if (overlappingCollider != null && overlappingCollider != physicsCollider && overlappingCollider.gameObject.tag == tag)
        {
            overlap = true;
        }
    }

    // Return
    return overlap;
}

// Collide velocity x
Vector3 xVector = new Vector3(velocity.x, 0.0f, 0.0f);
Vector3 xVectorEpsilon = xVector.normalized * overlapEpsilon;
if (PlaceMeeting(transform.position + xVector, "solid"))
{
    while (!PlaceMeeting(transform.position + xVectorEpsilon, "solid"))
    {
        transform.position += xVectorEpsilon;
    }
    xVector.x = 0.0f;
    velocity.x = 0.0f;
}
transform.position += xVector;

// Collide velocity y
Vector3 yVector = new Vector3(0.0f, velocity.y, 0.0f);
Vector3 yVectorEpsilon = yVector.normalized * overlapEpsilon;
if (PlaceMeeting(transform.position + yVector, "solid"))
{
    while (!PlaceMeeting(transform.position + yVectorEpsilon, "solid"))
    {
        transform.position += yVectorEpsilon;
    }
    yVector.y = 0.0f;
    velocity.y = 0.0f;
}
transform.position += yVector;

This is the most important code

PlaceMeeting is an overlap function to check if the player would collide with a solid at a given coordinate

The second code snippet is my collision resolution logic inside of FixedUpdate()

The code is almost exactly as I want it:

https://i.gyazo.com/bb799f005112c87dbd7f15d89a0342ab.mp4

As you can see the behaviour is pretty reasonable for a platformer

However - and you can't see this - the player is unable to jump sometimes

They'll be on the ground but the jump input will be eaten

..........wait

hooold that reading comprehension a second. I think I might be an idiot and this is just an input problem

[hearty hawk]

hey uh, I'm doing a topdown car game and I'm using rigidbody and forces for movements
Which makes the car to drift, and do weird stuff like sliding on the ground, on the car's X axis :I
How can I prevent the car from drifting and sliding sideways ?

[random sundial]

Hello! I have a quick question regarding ray casts in Physics2D (or in general?). I have a grid and for each cell in the grid I have to initially check if there's an entity present in it and what their layermask is. I was going to handle this with ray casting and I'm wondering what the performance differences are between the different casts (e.g. Physics2D.Raycast vs. Physics2D.Boxcast). I was going to use Physics2D.Boxcast since my cells in the grid are also squares... but is that a good idea at all?

Also a question regarding Physics2D.Boxcast...Assuming I have a square that I want to cast a box onto and the origin is 0;0 with a radius of 0.5... how would I go about casting a box exactly onto that square? Physics2D.Boxcast requires at the very least the origin, size, angle and direction. Does a direction of Vector2.zero go "outwards" from the origin or do I have to use something like:

var origin = new Vector2(-0.5, 0.0);
var size = new Vector2(1.0, 1.0);
var direction = Vector2.right;

Effectively casting a box from the left side of the square to the right onto the square.

[hearty hawk]

For the origin, you can get to the center of the square pretty easily, and for the direction, you could use the transform.right attribute of the gameobject your square is in, I guess

[timid dove]

If you want to just check if there's an entity present, why use RayCast/BoxCast at all?

Why not OverlapBox?

or CheckBox

[jolly brook]

Hey there! I have a quick question about collisions. I have a player and enemy, bot with a rigidbody. The rotation for the enemy's rb is frozen for all axis, movement is frozen on the y. But whenever the player comes to closes the enemy seems to tilt upwards. Vice versa, when the enemy comes to close to the player, the player gets pushed back. What is the reason for this and how can I solve this?

[random sundial]

It's just a difference between these two... I'm wondering if the first one works like that or if I have to work with an offset:

[timid dove]

OverlapBox is definitely what you want...

Boxcast will not expand outwards

It's a fixed size box that sweeps in a line

[random sundial]

Works for me... I'm not picky. 🙂 Isn't OverlapBox more or less the same as a BoxCast in this scenario though?

[timid dove]

It's simpler

It's boxcast without the sweeping

Just... "Tell me if there's anything in this box"

[random sundial]

According to the API you still get access to the Collider2D at the very least. I think that'll be more than enough for my use case.

[timid dove]

Yep

[random sundial]

Can you give a me a quick run down when you'd want pick a BoxCast (or ray cast in general) over something like a OverlapBox?

[timid dove]

Boxcast is when you want to simulate a projectile or something that will be moving through space

And you want to know what the first thing is that it hits

Like if you were shooting a laser gun you would use raycast to see what if anything the laser beam hits

Boxcast is similar but instead of an infinitely thin beam, it's like throwing a box through the scene (at lightspeed) and seeing if the box would hit anything on its path

It's useful for checking if an object would fit through an area without hitting something or simulating a "bulky" hitscan attack

[random sundial]

So I guess the big difference is that a ray/cast can move, while an overlap just checks a specified area once?

[timid dove]

basically

even though the "casts" "move" just remember they still do so instantly it's not over time

[jolly brook]

Anyone who can help me with this? 😊

[random sundial]

Awesome, thanks a lot for your help and explanation! 🙂 I think I get it!

[hearty hawk]

hey uh, I'm doing a topdown car game and I'm using rigidbody and forces for movements
Which makes the car to drift, and do weird stuff like sliding on the ground, sideways
How can I prevent the car from drifting and sliding sideways ? Like, just going straight where I steer

[timid dove]

Let's say your car is pointing towards the black arrow. The current velocity is the Green arrow.

I would take the current velocity (green) and project it on the plane whose normal is the forward direction (the black arrow). This plane is represented by the blue line. The projected velocity on this plane is the Purple arrow.

This purple arrow tells you your velocity that is not aligned with your car's current direction. (sideways velocity so to speak)

You can then apply a force like the Red arrow in the opposite direction as this purple velocity to counteract that sideways velocity. You can think of this as a friction force of the wheels resisting moving sideways

You can make the red force proportional to the purple velocity to act like friction, and tweak the coefficient until it feels right. If you use a high coefficient it will be very sudden, like you're on a track. If you use a low one, you will be a able to drift a bit.

I'd play with it until it feels right

(of course do all of this in FixedUpdate)

[hearty hawk]

That's what I tried to do in the first place, but I couldn't even figure out how to get to the purple arrow stuff

As long as the car is perfectly vertical, this is easy :T Just need to add a counter force with the same amount as velocity.x
but what if the car it rotated by, say 30° ?

This is where I'm stuck : trying to get the velocity, rotated to match the blue line when the car is rotated

[timid dove]

You just need project the velocity vector onto the plane defined by the facing vector

something like this:

wait is this 2D or 3D

btw

[hearty hawk]

It's 2d

[timid dove]

I'm just gonna use the Vector3 functions because's no built in projection function for Vector2

// black arrow
Vector3 forward = car.forward;
// green arrow
Vector3 velocity = rb.velocity;
// purple arrow
Vector3 sidewaysVelocity = Vector3.ProjectOnPlane(velocity, forward);

so now sidewaysVelocity is the purple arrow from the diagram above

so then you can apply a force proportional to -sidewaysVelocity (the red arrow)

[hearty hawk]

Mmh, what does project do concretely ?

[timid dove]

It's a vector projection

so given a and b you can get a2

b is the "forward" vector from above

and a is the current velocity

[hearty hawk]

oh, ok

[timid dove]

So a2 is just the "sideways" part of the velocity

This is a better representation of what we're doing

We're projecting the blue vector onto the plane defined by the straight-up vector in this image

which gives us another vector that is lying flat on that plane

[hearty hawk]

oook

[timid dove]

I suggest trying to maybe Debug.DrawRay on all those vectors to visualize this in your game

[hearty hawk]

ye ok, I was trying to do that stuff, but with maths and stuff I didn't understand :I

This works wonders \o/ Thanks !

I've spent 5 hours trying to figure out this

[timid dove]

I find that this kinda stuff is pretty intuitive if you just draw out what's happening with arrows for velocities and forces, and get a good concrete idea of what you are trying to do exactly. You can figure out the maths part of it later once you have a good expression of exactly what you need to figure out how to calculate

[magic crow]

It might sound obvious, but I've been teaching myself via tutorials and they haven't explained this yet - I've gone to edit the script and it's behaving oddly

[sonic spire]

can someone help me with my ragdoll? the limbs are freaking out and im not sure how to fix it.

also im trying to make an active ragdoll

[patent idol]

guys whats the vector 3 direction of the mouse input?

and how can i get it ?

[storm shore]

Maybe try this: https://docs.unity3d.com/ScriptReference/Camera.ScreenPointToRay.html

[patent idol]

thank you 🙂

[storm shore]

I'm trying to create an object with this sort of physics motion. I've been trying to use a springjoint with no luck. Any ideas?

[viral ginkgo]

@storm shore bunch of hinge joints like a rope could do it

[flat dune]

Yo, wondering if people offer support here for a logical type of code?
Basically (mind the texture, sync issue that will be resolved tomorrow), got a player who is a sphere.
Sphere moved by adding force based on WASD input.
Attached to the sphere is a beetle, and we wanna make it look like the beetle is pushing the sphere around.
I understand that I can rotate around the sphere, on a certain axis (usually Vector3.up, the sphere was upright and stationary), however I want the beetle to stop rotating if it is behind the sphere (i'd assume using the sphere transform.forward * -1 somehow?), but also, to still rotate around the world's vector3.up as opposed to the sphere's...

@ me or reply if this is something you can help with, as I'm sleeping now. Thanks! 😄

[stuck bay]

"It's not a bug, it's a feature"

[sonic spire]

lol

[timid dove]

so you want like Katamari Damacy

[reef lance]

I would make them children of the same object, that should automatically handle orientation and location.

[storm shore]

So the effect I would like to achieve would be for the cube on top to follow the sphere more like a rc car antenna but instead it just kinda goes wild. Right now I'm just getting the direction from the cube to it's target (a point above the sphere) and then I'm just using Rigidbody.AddForce but as you can see it overcompensates. Not sure how to avoid that.

[timid dove]

Scale that force down

[storm shore]

Scaling the force down causes the cube to take forever to catch up to the sphere

[timid dove]

Maybe make it not linear. Make it proportional to the square of the distance

[reef lance]

Might be easier to handle manually instead of through force.

Create formula that finds a point on a sphere given an xz direction and an angle.
The input to xz direction is the opposite of the force direction and the angle is based on the time since the last force application combined with the magnitude of the force.

[sly spade]

@storm shore you prob used the spring joint wrong

[magic crow]

I'd like to make the rigidbody of my vehicle either not rotate on the Z axis while airborne, or severely dampen the rolling. I thought I had it with this code - there's a ray pointing down from the car that detects if there's ground right below, and if not, the car is not in the grounded state

I apply a force to the rigidbody then add a transform on the X axis

I would have thought adding a vector3 of value (n, 0, 0) would say to exert zero force along axes Y and Z, but apparently that doesn't mean clamp those values

I had the idea to modify transform.rotation.z directly, but apparently that's a read only value

[exotic coyote]

Anyone here a phycics guru,i need help with collisions in my racing game 🙂

[magic crow]

m not at all, but I have been dealing with lots of issues so maybe I can help

what's the issue?

[exotic coyote]

Basically my cars/spaceships when hitting the boundries of the racetrack either snag or clip through the mesh collider,everything is set to continuous and interpolation is on

still getting weird results

[magic crow]

ok, go into your game settings, and there's a value called depenetration velocity

I was having the same issue, you want to up that setting by an order of magnitude

[exotic coyote]

What value would be suitable you think?

[magic crow]

edit > project settings > default max depenetration velocity

I have mine set to 1000

and no issues since

give that a go

[exotic coyote]

Let me try

It looks better but a new problem started

If going to fast it just breaks the rotation,must i lock the rotation of the rigidbody?

[magic crow]

just looking at the vid now

ok, I see what you mean

so you hit a wall, and it sort of sticks the vehicle at a certain rotation

[exotic coyote]

yes

[magic crow]

does it return if you just leave it?

[exotic coyote]

if it hits it once then yes

[magic crow]

I have had a similar issue, but long since fixed

are you using a box colider?

*collider

[exotic coyote]

mesh

[magic crow]

ok, I don't think this will fix the issue, but I think it will help

[exotic coyote]

This is the real collider not the wall u saw

[magic crow]

in the start , set the center of mass for the rigidbody slightly lower on the y axis

for example:

com = new Vector3(0, -1 , 0);

theRB.centerOfMass = com;

that's what I've done for my game to mitigate rolling slightly

However I have a hunch that what you're seeing is essentially a byproduct of physics and high velocities, and that you may need to self-correct somehow

[exotic coyote]

because my velocity is quite high

[magic crow]

I had another thought... And I don't quite know how to word it, but a lot of the times a transform position is related to the current position of the object - but you may want to map the Z axis to the world somehow

so that instead of rolling compared to its own position, it rolls compared to the ground position

[exotic coyote]

Not using transform position

using add relative force(acceleration)

[magic crow]

ah right that makes sense

well the center of mass should help it re-balance, but I don't think it will prevent it from happening.

hopefully someone else can help further!

[exotic coyote]

Thx alot for your time man

much apreciated

[magic crow]

np, game looks really good, hope it gets sorted!

[exotic coyote]

I just fixed it XD

constratints tick x axis

[magic crow]

ok, I fixed my rolling problem. I see that I was actually adding values to the existing euler angles. I simply made a new vector3 where I added x, y and z clamped to +-1 of itself, and that seemed to dampen the airborne roll significantly

[stuck bay]

Hi guys, I would like to stop a collision event to reach other components if some conditions aren't respected.
o be more precise, I want to add a sphere boolean operation on top of any collider, is that possible? DOTS or not.
I'm using a rigibody for now so it won't be possible, but I plan to use some kinematic object.

[magic crow]

if it helps, you can add .isTrigger to the collider via code, will that help?

I'm still not certain what you're trying to achieve though

[sonic spire]

how would i make a self balancing ragdoll?

[viral ginkgo]

@sonic spire
1- Kinematic rb animated character
2-Dynamic rb ragdoll character
3-Attach each limb pair except the hip with a rotation constraining joint (can use configurable joints)
4-Make kinematic characters hip inherit its rotation from the dynamic character

With these, you should have a proper ragdoll animation following

And then if you wanna make it stand up, you can add some forces and torque to keep the body up however you want
Can do any of these:
-You can apply upwards force from head
-You can use some torque to rotate a part of the body (preferably close to center of mass) like hip or spine and other parts will follow

[magic crow]

I have an issue with wheel colliders catching on terrain. At first I thought it was the box collider, but I tried adding some other colliders, then removing them all (apart from the actual wheel colliders), and it still happens.
The way it manifests is while travelling over uneven terrain, if it catches, the vehicle will spin around where it's caught, or on launching over a slope, it will turn. I don't really have any clue how to counteract it, any suggestions?

[magic crow]

ok my gosh I'm tired, but I think I've found it... I think

so the ray fires down directly from the car and rotates the position in accordance with the normal of whatever the ray hits

but this is only ideal when the vehicle travels up a nice broad slope. As soon as a curve is involved, I think this is what's spinning the car

so I have to work out how to transform only on the x axis I think

nope. It's definitely the wheel colliders clipping through the ground, I see them

FML

[foggy rapids]

vehicles are really difficult to get right, most people achieve more success by simplifying the physics

or using an asset from the store 😛

[magic crow]

It's so annoying, I bought Edys Vehicle Physics but it wasn't what I wanted

Then I followed a simple tutorial and it was perfect, but it relied on transform position and didn't have a usable collider (it used a sphere and updated position based on that)

[foggy rapids]

this one? https://www.youtube.com/watch?v=TBIYSksI10k

[magic crow]

So I tried to adapt that to get where I wanted and I got so close

It wasn't that one but probably close. I'll take a look

Yeah it's almost exactly the same as that vid. The only problem is that I couldn't find a non-intrusive what to add a collider, so the car just travels through everything because the sphere is the only solid object, and it also just shoots straight up vertical surfaces. Adapting the rigidbody to the car and adjusting everything took care of that, but then introduced these new problems

[foggy rapids]

the trick is to use more than one for different purposes.
what do you need to collide with other than terrain?

[magic crow]

I wanted to collide with trees and other cars

But I couldn't make them work together

[foggy rapids]

you could try using a cylinder instead of a sphere it would work in a similar way except you'd have to actually turn it. Then it could encompass the entire vehicle and serve the purpose of colliding with terrain
then use a box collider to hit trees and other players.

seeing working solutions using wheel colliders are few and far between in here 😦

[magic crow]

My original also used wheel colliders, but I think they were more to provide suspension to the car mesh

Is it possible to set a box collider to ignore ground collisions and only interact with another group?

I imagine so, I think I need some sort of walkthrough

At least I've learned things I suppose

[foggy rapids]

yep

vehicles are really difficult

[magic crow]

I don't understand why though, it just seems to be that wheel colliders are really janky

[random sundial]

Hey guys! I have an issue with Physics2D.OverlapBox and multiple close by layers... and I bet I'm just using Physics2D.OverlapBox incorrectly. This explains my issue:

Basically I use 0.5;0.5 as the origin of the overlap and use the size of "one". The overlap seems to touch Layer A instead of Layer B though. I assume I'm going to have to use some sort of margin to make sure Layer A isn't touched by accident?

e.g. size = new Vector2(0.95, 0.95) instead ?

[wide nebula]

Does the collider have to match the entire width of a tile? Can you not just use a raycast?

[storm shore]

I'd like to make a sphere look an act more like a blob. Is there a simple way to do this via physics or should I look more into using a shader?

[random sundial]

Actually in this case I just want to check which layer that cell belongs to... so technically I could just cast a ray into the center of each cell, but since this'll happen lots of times I figured an overlap might be more performant.

[wide nebula]

Not sure how it would be more performant. And why do you need to know every frame which layer every tile is on?

[random sundial]

Ah, not every frame, just once in the beginning. It's a large grid though. I was under the assumption that overlaps are faster(?) than raycasts.

[wide nebula]

Maybe? You would have to profile it. And it might be negligible.

Optimize if it's a problem, just use a raycast and save yourself the headache.

[calm plank]

So, I think I'm doing something dumb with a raycast here, but I can't seem to spot it. I want to cast from the center of the camera forward into the scene.

                RaycastHit hit;
                Transform rayOrigin = Camera.main.transform;
                int mask = 1 << LayerMask.NameToLayer("UI");
                if (Physics.Raycast(rayOrigin.position, rayOrigin.forward, out hit, Mathf.Infinity,
                    mask))
                {
                    Debug.DrawRay(rayOrigin.position, rayOrigin.forward * hit.distance, Color.yellow);
                    Debug.Log($"Hit: {hit.transform}, {hit.transform.gameObject.layer}");
                }
                else
                {
                    Debug.DrawRay(rayOrigin.position, rayOrigin.forward * 1000, Color.white);
                }

But the rays are like... all over the place seemingly at random. Straight up and down the left and right of the screen, sometimes random forward angles, I can't seem to make sense of it.

Potato-quality demonstration

I thought that maybe .forward wasn't right for some reason, but if it weren't I'd expect the rays to be consistently in the same wrong direction, not random/crazy

Is there something about using Cinemachine that makes it a bad idea to use the main camera's transform maybe?

[calm plank]

Tried it with ViewportPointToRay instead, same craziness.

[foggy rapids]

first page of the manual says why 😄

Cinemachine does not create new cameras. Instead, it directs a single Unity camera for multiple shots

try using one of the virtual camera's transform

[calm plank]

Yes, I know. That's why I would think Camera.main (the one with the brain) would work regardless of which VCam happens to be active

Is that not how it works?

I thought it was the active VCam was positioning the "real" cam

[foggy rapids]

no idea, but seeing how it works with the correct virtual camera might help. You might also try looking from another direction. If it was working you'd only see a white dot in the middle of the screen

[calm plank]

It is a good idea to try. How do you query the "Live" VCam for a given brain?

She actually has two following her to allow a "zoom in" view so I can't assume it a particular one

[foggy rapids]

i dunno i never used cinemachine i just thought you'd keep track on your own somehow 🤷

could be that it works just fine and the way it's drawing lines is weird due to the type of camera

[calm plank]

I'll look into it at least, no other leads 🙂

[summer saddle]

Hi, is there any way to make OnTriggerEnter trigger with a terrain? It's the only thing it isn't triggering it

Hmm i see it sometimes can trigger it, but it's like 1 time of 10 🤔

In continuous dynamic detection mode

[calm plank]

To followup on my issue above, it seems it DID have to do with Cinemachine. I wasn't wrong that the brain "pilots" the real camera into position, but apparently some weird stuff happens per-frame, and you get crazy results if your Update() happens before it's decided on a position for that frame. So in OnEnable() you can do:

CinemachineCore.CameraUpdatedEvent.AddListener(OnCameraUpdated);

Then:

void OnCameraUpdated(CinemachineBrain brain)
          {
              Camera camera = brain.OutputCamera;
              <whatever>

If you raycast from there, all works as expected.

[languid shoal]

I'm thinking collisions is a physics thing so
I've got some lab equipment in my project, all of it has mesh colliders, which means I can't put stuff inside it - how would one get the ability to do so?

[jolly brook]

I am working with a NavMesh and an Enemy with a rigidbody, but I have a very weird problem where in some cases, when it seems to get stuck, the FixedUpdate function just does not get called at all anymore. And I honestly have no idea why that's happening.

[lavish remnant]

;-;

how can i make it more real?

this is what i want

[gentle plume]

But why?

[timid dove]

Needs more context. Do you have any Colliders there?

Also is this normal physics or like ECS?

[gentle plume]

No. I do provide all required data, don't I?

[timid dove]

Because I see float3

[gentle plume]

this is ecs

well, that's basically Unity.Mathematics

[timid dove]

I'm asking if there are actually any colliders in that area

[gentle plume]

No, that's for sure. I thought it detects collisions with the box in input arguments

[timid dove]

It casts a box through the scene and tells you if it hit any Colliders

[gentle plume]

lol. That's a big surprise for me

[timid dove]

Really? I'm confused about what you expected ot does : 🤔

[gentle plume]

So I specify a box center, its extents, the direction of the ray to cast. I expected that it will tell me if the ray intersects with this box

[timid dove]

Nope

[gentle plume]

Just like a simple raycasting operation

sad

[timid dove]

You specify the center of the box, the extents of the box, and the direction in which to cast the box through the scene

You could use Plane.Raycast for pure math kinda stuff? Not quite a box though :)

There's also Collider.Raycast

[gentle plume]

Alright then. I think its pretty easy to implement myself. Thanks for explanation

[timid dove]

Not sure if this stuff is available in ECS though

[patent idol]

if i set math.infinity distance in Ray would it be heavy to compute for unity?

[timid dove]

Nope

[patent idol]

if i make alot of rays

100s

[timid dove]

It's the same as any other raycast i believe

[patent idol]

alright

thanks

[worn meadow]

hello, i cant apply psychic material. i created psychic material but when i drag it on some object nothing happens. when i want to change psychic material on some object the material that i created doesnt show there

ok i just fixed it, i tried to apply 3d material to 2d object

[bronze spruce]

physics makes me go YES

[sly wave]

Hey I have a question. So basically I have my character checking if he is grounded with a simple raycast/check sphere to see if there's a ground under him and it works fine. The only problem is that whenever I put it on top of a mesh collider it does not detect the mesh collider as ground. I checked everything. Tags are fine, the collider works, I even created the mesh physics material but he still doesn't trigger IsGrounded variable on custom meshes. Any clue on what I'm doing wrong?

[glacial jolt]

debug out all the objects hit by your raycast to see if it's being hit at all

[sly wave]

@glacial jolt Without the layer mask?

[glacial jolt]

yea, try it initially without any layer mask passed into Raycast to get all possible objects

then narrow it down to see which part is causing it not to be found by your ground detection

[sly wave]

it does

@glacial jolt ok, i found something. It's weird tho. Basically the sphere doesnt check the custom mesh at the height in which the collider is at... it kinda has to be inside the collider.

this is true (thats a normal cube collider)

yet this is false

but this is true

the last 2 are from the custom mesh

[glacial jolt]

possible that the position of the sphere is not centered on the transform?

[sly wave]

it is. i made a script just for that that uses "transform.position" as the origin

i have a theory but it makes 0 sense

For some reason my brain is telling me that it might have something to do with the normals of the mesh. It makes no sense since the mesh that is causing problems is a cylinder from unity itself

[timid dove]

can you turn gizmos on? Hard to see what you're trying to show in these images

With gizmos on you can see the colliders in green wireframe

[late ore]

Hey, is there away to make an object ignore capsule collider of another object?

Im having this problem

[timid dove]

https://docs.unity3d.com/Manual/LayerBasedCollision.html

[late ore]

Thank you so much yo! 😭 You the goat fr

[daring furnace]

How can I calculate how much force I need to add to Rigidbody2D's AddForce in order to guarantee that my player jumps can reach a platform of a certain height?
My platform heights are based on my camera's viewport, so I'm concerned that with different screen sizes on different devices, the viewport will change, so the platforms would be at different heights and the player's jump won't be able to reach it.

EDIT: Kind of worked around this for now, but would still appreciate an answer

[merry mulch]

Hey there, so I have a smol problem rn and I think it's collision based

basically when I get close to an objects edge, my jump starts getting messed up and I don't know why. here's an example

https://gyazo.com/7859a31a3012e3addbbd475743292464

I made mesh colliders for these "treestumps" because there are no cylindric colliders afaik and capsule colliders aren't doing it

but for example, when I jump against a solid object, collision works just fine

like this

https://gyazo.com/444cfda3277cf0c4c30b39a98bde1180

[glossy lintel]

Hi all, I'm currently planning a project for a conference competition this summer and I really want to leverage Unity's physics/particle system for it. My project proposal is simulating how COVID-19 particles travel through the air in an enclosed room. I was curious what your alls thought on the possibility of this being implemented with unity is?

Rather simple set up I just want to have a single source that would emit the covid particles, they'd interact with the air particles and objects in a room. Obviously this would probably require a hefty amount of particles and some acceleration techniques but based on what I know of Unity so far this seems to me like a task Unity is well suited for

Worth noting this is just a student concept competition so this doesn't have to be something with bleeding edge levels of accuracy

[timid dove]

I'd suggest using VFX graph or a compute shader

many thousands of particles is a bit too much for the normal particle system (shuriken)

[glossy lintel]

I agree actually I think that'd be a smart idea

Good way to off load it to the GPU

[minor dew]

Hey guys

I just want two cars to move towards each other and when they connect, I want the one with the higher mass to push the other one. I almost did it, with wheel colliders + box colliders and a rigitbody setVelocity script. But the dang cars start rotating once they connect.

I feel like there's a much simpler way to do this

[viral ginkgo]

@minor dew it sounds to me like you are after realism

maybe you are working a casual-like like game

maybe you'd wanna have just a box for a car

it will get rid of a great deal of complexist and your results should be similar to what you are expecting

[minor dew]

That's what I did next, I deleted all the wheel colliders and just used box collider for the cars and I will make the tires turn with animation. But there is still some rotating and once it rotates they start spinning and rotating more

But I think it is because they are just moving "forward" related to their facing

Tomorrow I will try to make them go forward in world position so when they collide, even if little rotations happen due to physics they will still try to move past each other

But in this way, I feel like there is still too much of a chance for error because one might slip eventually due to physics

I'm most likely missing even a simpler way to do this

Is there a way to make objects push each other with rigidbody and colliders without any chance of sliding to the side and/or rotating

Like a straight line

[minor dew]

Yes it's just going to be a casual game where cars push eachother to the finish line. 3D with a birds eye view

But I need that straight line movement desperately. I'm usually fine finding answers on youtube but this time I don't even know how I can search this

[timid dove]

This doesn't sound like something you would normally use the physics engine for

[minor dew]

So no rigidbody just colliders and code in their mass?

Or their pushing force or whatever

This is my first game so pardon me if I'm way off

[viral ginkgo]

@minor dew are you looking for a perfect solution?

a little slipping and stuff acceptable?

@minor dew here is what i would do:
inside oncollision stay, i would try to fight against rotation
and align the cars forwards (via pushing them together)

and also dampen cars relative velocities
on collision axis plane

[stuck bay]

hey guys my player does not collide with objects

i have setup box colliders

on the objects it should collide with

[crisp sable]

The player needs a collider too I think - it can be a trigger

[stuck bay]

ok let me try

[timid dove]

two things - player needs a collider - but also your player is kinematic - which makes me wonder how you are moving the player

[stuck bay]

http://somup.com/crfZelFYSA

[timid dove]

generally kinematic rigidbodies don't respect forces or obstacles

[stuck bay]

ohh

this is my player movement script

[crisp sable]

aha i bet its setposition

[timid dove]

Yeah - Kinematic rigidbodies are like unstoppable forces

they go where they want, and ignore collisions (although they will push dynamic bodies out of the way)

[crisp sable]

there you go then, uncheck that box 😄

[stuck bay]

got it

[timid dove]

Well that's a whole different can of worms - but yes your player will then respect collisions

[stuck bay]

i fixed it

it works now thanks

[digital pawn]

heya, ive been making a ground detection system but for some reason whenever i hit the wall (even if standing stil against it) it counts as collision despite the ground collider being quite a bit away from the wall? any ideas on how i could fix this? (red = groundcoll (isTrigger), blue = player (regular square collider2d, cyan = wall(mesh collider))

all i know is that offcourse it sets the player in the wall before the collision correction and it counts as detection (i assume, anyways), but i have no idea on how i would fix this

oh and its apparently fine when the wall is on the left side, but not right?

huh i fixed it by making the hitbox a bit smaller, but i assume it'll happen again at a lower fps, so it's still a problem

[civic field]

making the collision detection continuous might help if it's a clipping issue

[stuck bay]

I have written the code of collision right but still it's not detecting collision with obstacle

idk why

pls help

i have tagged obstacle too

[foggy rapids]

where is the obstacle?

[stuck bay]

it comes when the game starts

it's a prefab

will instantiate after game starts

[dense moth]

yo, Im trying to use physics overlaysphere to detect only colliders on the 'enemies' layer using a layermask, but for some reason its detecting colliders on all layers for some reason?

the room the player is in is definitely set to default, Ive checked this during run time, so I have no idea why the colliders are being detected

figured it out lol

Im missing a parameter in the overlay call

[digital pawn]

sadly already have continuous on and it's still an issue

[foggy rapids]

to avoid that, you need to just let the collision happen and not handle it, or also detect when you're against a wall to prevent movement in that direction

[slate wasp]

Hello, can anyone help me figure out how to make my walls ultra solid. I am pretty new and am taking this udemy course and my walls work until I increase my player speed to anything above ten which is painfully slow.

[foggy rapids]

try continuous detection mode, make them fatter, or use casting functions

[slate wasp]

Ok I'll try that

Where is continuous detection mode? I was told to use the box collider, is it a different one?

[foggy rapids]

that setting is on the rigidbody

[slate wasp]

It didn't work. Does adding a material to the colliders help with anything?

[timid dove]

it won't help with tunnelling

which is the problem you're facing

ways to fix it:

• Decrease the game's fixed timestep
• Make your walls thicker
• Make your player thicker
• Change Rigidbody collision detection mode
• Use custom box/capsule/sphere casting in FixedUpdate to detect obstacles

[slate wasp]

Ok thank you I will try those

[crisp sable]

and if all that fails, there's a pretty old script I found called dontgothroughthings, that uses a raycast to detect if a wall is coming, and through some sorcery, prevents clipping through walls

I couldn't get it to work when I tried, but apparently its a thing, ill find it for ya

https://wiki.unity3d.com/index.php/DontGoThroughThings

I didn't really spend that much time trying to implement it, so not getting it to work is likely my fault

[slate wasp]

Yeah I'm like super new to coding and unity so it will probably take a bit to understand a lot of the stuff

I appreciate everyone for trying to help though

[supple sparrow]

That's not sorcery, that's the ray/collider casting MICKEN and PraetorBlue were talking about 😉

[civic field]

https://docs.unity3d.com/ScriptReference/Physics.Raycast.html

you give it an origin and a direction and it gives you whatever it hit first

[hoary scroll]

I'm trying to have a box that the player can only push around a designated area. So I need a box that collides with the player and some walls, and walls that collide with the box and not the player.
How would I go about doing this? I'd imagine there's a "one-off" solution as well as some sort of general solution (using layers maybe?).

[timid dove]

Layer based collision is the way to go for sure

https://docs.unity3d.com/Manual/LayerBasedCollision.html

[hoary scroll]

OK I'll look into it and come back if I have any issues

thanks for the direction!

[timid dove]

And just as a side note, there is indeed a "one-off" solution as well, where you can tell the physics engine to ignore collisions between two specific colliders: https://docs.unity3d.com/ScriptReference/Physics.IgnoreCollision.html

[hoary scroll]

ah, that's also useful to know, thank you

[summer glen]

does anyone know is it good to combine collision meshes into one big mesh

and under 65k triangles

or better to have smaller meshes

does it affect occlusion culling

[magic crow]

Hi, I have an issue I need to resolve. I have a car object following a sphere with a rigidbody as the control method. That all works great. The problem comes because I'm using transform.position to move the car to the sphere location, the car can move into a solid object up to the point of the sphere

I've tried messing around with collision layers and adding extra colliders to the sphere, and those don't work. What's the best way to have my car collide with objects properly?

I've tried totally recreating the vehicle and have it move with real physics, and that worked up to a point, then it started clipping through terrain at points, and basically presented a new set of problems

[calm plank]

If you're teleporting it how is it supposed to collide?

I think you're going to need to do your second approach with actual physics and figure out those problem

[magic crow]

Well, my idea was along the lines of adding a second box collider to the sphere object, then place that in a collision layer that ignores the ground, but interacts with other objects