⚛️┃physics

[mossy iron]

this.transform.position += velocity*Time.deltaTime. Assuming you're at max possible velocity (so theres no acceleration)

The reason I used ithe character controller is because its apparently supposed to handle stairs for you, but I guess that doesn't work in 2D.

[mental mica]

hello, does anyone know any open source C# script that does physics?

just like rigidbody, but open source?

[timid dove]

PhysX and Box2D (Unity's physics engines) are both open source. They aren't C# though

[high shore]

I'm trying to create a physics prediction in a PhysicsScene, but if i create it by code it tells me that the scene with the name "PredictionPhysicsScene" already exists. (Line 42 and 38)

[mental mica]

thanks, but i need it to be c#

[minor cosmos]

I'm not sure if this counts as physics but here we go:

I am using FromToRotation to rotate towards an object in a 2D game, however, my Yaxis is facing downwards and i don't know how to flip it without messing the rotation up.

Code(update method):
Vector2 direction = Player.position - new Vector3(Shoulder.transform.position.x, Shoulder.transform.position.y, Shoulder.transform.position.z);

Shoulder.transform.rotation = Quaternion.FromToRotation(Vector3.right, direction);

Note: the black capsule is not the player.
How the Y axis look like:

[hushed frost]

Hi, I have an issue with unity 2D collision. Basically, when 2 units with dynamic rigidbodies collide, they push each other. I want them not to push each other but their collisions must not be ignored. They are moved directly by velocity.

[timid dove]

The collision is the thing that pushes them. Your request is a bit of an oxymoron

[stuck bay]

How do i make collisions without rigidbody

it just messes up my game

[timid dove]

You don't. There are no collisions without Rigidbody in Unity.

kinda depends on your definition of "collision" of course

But that's the unit of "physically simulated object" that can experience and react to collisions

[stuck bay]

Collider?

[stuck bay]

Rotate by 180 on z axis?

[stuck bay]

😔

[minor cosmos]

It sadly did not work, the rotations stopped working completely when i did that

[stuck bay]

Wat how

[minor cosmos]

I tried finding a way around it

[stuck bay]

Have you tried rotateAround

[minor cosmos]

Yes i tried that too

[stuck bay]

:thonk:
there goes my wild card lol

[minor cosmos]

I did a simple script to flip the child gfx locally

Thats my work way around it

So he basically aims

And the graphics is handled separately

Shooting aswell is handled from the gfx's side

[stuck bay]

Hey guys! I got some issues moving my object from A to B in 2D gradually. I tried multiple ways and what I found was this:

1. rigidbody.MovePosition(destinationPosition * movementSpeed * Time.deltaTime) << that overshoots the position, the rigidbody doesn't come to a stop.
2. rigidbody.velocity << same problem
3. gameobject.transform.Translate << same problem

in all cases it's inside an if statement in FixedUpdate comparing the Vector2.Distance between A and B

What could be the correct way to get an object start at A and stop at the exact position of B?

[timid dove]

void FixedUpdate() {
    rb2d.MovePosition(Vector2.MoveTowards(rb2d.position, targetPosition, speed * Time.fixedDeltaTime));
}```

[stuck bay]

Thanks man! I noticed my problem is also in receiving the correct data, but I found out after using this. Thanks for helping me further.

[stuck bay]

Wat version of unity are you using?

[minor cosmos]

2021 lts

[stuck bay]

Have you tried using anything besides from to rotation?

I’ve never seen that before

Or is it the only thing you can use

[minor cosmos]

Its the only thing

Since lookat function(cant recall exact name) doesnt work properly on 2D

[stuck bay]

Why is direction a vector2? I thought Quarter irons are vector4

Oh it’s 2d

[timid dove]

All you need is:

Vector3 direction = target.position - transform.position;
transform.right = direction;```

[minor cosmos]

Will the Y axis be flipped?

I need the y axis to always face upwards

On all 360 degreese

Degrees*

[timid dove]

you'll need special handling for right/left sides

[stuck bay]

Can a 2d object even rotate on the y axis?

[timid dove]

Of course

[stuck bay]

Doesn’t 2d mean it can only rotate on one axis

[minor cosmos]

2D objects rotate ONLY on the z axis

[timid dove]

there are no 2D games in Unity anyway

The best way to flip a sprite around is rotate it 180 degrees on the y axis

[stuck bay]

Wat

[minor cosmos]

I already found a way around

[minor cosmos]

.

[stuck bay]

Oh

[lone narwhal]

Hi guys. How do I add velocity to this script? I want the object to be constantly moving, but you can change the direction it's moving (up/down/left/right)

Sort of like Snake 2D

[stuck bay]

So since collision only works with rigid body, how do I make it so that no bouncing or anything happens?

I just want collision

[timid dove]

Collision and bouncing are one in the same

You can use physicmaterials to affect the bounciness

Or you can use the contacts modification API to change the nature of the collision entirely (3D only)

[real belfry]

do you guys have any idea on how do I increase the speed for Hinge Joints? i'm trying to make a pendulum like obstacle

[timid void]

why not just rotate the pendulum through code?

using rigidbody.moverotation instead of transform.rotate

or addtorque or whatever

[patent crane]

how do I prevent a RigidBody 2D from sliding on slopes without adding friction?

[real belfry]

my bad. I just started learning unity but I'll definitely try rigidbody.moverotation

thanks! @timid void

[gloomy blade]

if I have a child object A that will never move on its own, but whose parent object does move and drags A along with it, should object A have a static or a dynamic/kinematic rigidbody?

[timid dove]

In physics, the period of the pendulum is determined entirely by the length of the pendulum. The longer the pendulum the Longer the period of oscillation.

The only way to change that is by adding extra forces/torques

[timid void]

angular velocity is proportional to the sqrt of the length; speed is proportional to the sqrt of the length and the initial angle/amplitude

[split girder]

Any ideas why NavMesh is ignoring Agent values?

[unique cave]

#🤖┃ai-navigation would be better channel

[rare dove]

Would CompositeCollider2D cause lag if used on large tilemaps?

[unique cave]

Cause lag on what part of the game? When enabling the composite collider or on every physics step after that?

[rare dove]

physic steps

[unique cave]

According to docs:

Using both components [Tilemap and Composite Collider] together reduces the number of individual Collider shapes involved in a physics update, which reduces the amount of calculations required, and minimizes the impact on performance.

Generating the composite collider can take some time tho

[mossy iron]

Implementing my own 2D physics for a platformer/beat-em-up game. Using boxcasts for ground/wall/tilemap detection.

Is there a way to avoid the whole "going so fast that you clip through the wall/ground" thing when using boxcasts?

[mossy iron]

Should I really just be using a Dynamic Rigidbody 2d?

[rare dove]

You plan on allowing the player to go that fast?

I dont think boxcasts allow this kind of clipping if you do them every frame

[tender gulch]

Implement custom continuous collision detection I guess. Something that unity physics can do for you if you use dynamic rigidbodies.

[carmine basin]

Got a question - I'm looking to implement some kind of stabbing/slashing physics so that objects get stuck in another when a sharp edge hits a penetrable object
I know I could check for physics materials for the latter part but how would I approach the "getting stuck in another object" part? I'm thinking I could use configurable or spring joints for it, perhaps?

since I only need it to slide on the axis of slash or stab

[rare juniper]

I'm not sure if this is the right channel for this question, hoping I can get some help though. I'm trying to simulate the orbital trajectory of a real life satellite. Right now, I'm using a technique known as orbital propagation to calculate the next position of a satellite, where the input is time. Would it be more performant to use the Unity physics engine to move the satellites and just use orbital propagation periodically to correct the satellite's position if needed? Or should I avoid the Unity physics engine and just move the satellite based on the orbital propagation calculations? Right now, I'm just calling the orbital propagation method and passing in DateTime.Now to get the current position, and then I update the transform

Side note, anyone know how to create an ellipse in Unity to render an orbit ring? Right now we're using the LineRenderer, but there are some issues with it, and it's not very performant when the orbit is large

[scenic compass]

New user here! Trying to emulate marble physics in my current Unity Poject but I'm having some difficulty.

The ball falls and rolls but it doesn't have the speed or lack of friction that your typical marble would have.

[scenic compass]

I keep increasing the mass but it continues to move really slowly

I'm creating and editing a physics material to the ball to see if that would change anything.

Following this for the marble:

WOOOOO IT WORKED

now i just have to edit the track a little so that it doesn't fall off

IT MADE IT TO THE BOTTOM!! heck yeah!!

[earnest nymph]

so i made a level in blender and imported it to unity

would i need to add a box collider for every floor/wall and obstacle? manually? it would be quite tedious...

is there a quicker way to add colliders to all of the floors/walls?

[mossy iron]

Yeah the player might move pretty fast.

All I am doing to stop clipping is:

  moveDirection.x = Mathf.Clamp(moveDirection.x, 0, 1);
if (IsTouchingRightWall())
  moveDirection.x = Mathf.Clamp(moveDirection.x, -1, 0);

IsTouchingLeftWall() just does a simple boxcast, where the box is more or less the left-half of the player sprite.

{
  int wallLayer = 6;
  LayerMask wallLayerMask = (1 << wallLayer);
  Vector2 boxCastSize = new Vector2(wallBoxWidth, wallBoxHeight);
  RaycastHit2D boxCastHit = Physics2D.BoxCast(this.transform.position + wallBoxDisplacement * Vector3.left, boxCastSize, 0f, Vector2.left, 0f, wallLayerMask);
  if (boxCastHit.collider != null)
    return true;
  else
    return false;
}

[mossy iron]

This bit of code here is just in FixedUpdate().

I suppose what I should be doing is checking if my updated Transform is intersecting the terrain. In other words, check if playerCollider.bounds.Intersects(tilemapCollider.bounds) [my syntax is probably wrong], and if it does, do something. I suppose just teleport the player out. I'll have to look up what other people do

[unique cave]

Is there a reason not to use mesh collider?

[earnest nymph]

yeah thats what im doing

but i was wondering if there was a faster way

[unique cave]

In what way faster?

[steel pewter]

Hello all, I have an OnCollisionEnter and OnCollisionExit on the same script for a fast moving rigidbody. For some reason, only OnEnter is being called sometimes and OnExit is not. I've turned the edit solver iterations way up so it's solving much more. To clarify, both are being called, but sometimes OnEnter is called and the exit isn't picked up.

Is it possible that it's moving so fast that OnEnter is called but OnExit isn't? Is that even possible?

[hazy birch]

@unique cave All my ground objects has a mesh collider but when i give to my player rigidbody it's not collide any reason ?

[unique cave]

Dynamic objects cant use non convex mesh collider

[hazy birch]

I have a convex

[unique cave]

And none of the colliders is trigger?

[lilac comet]

Hello guys, I have this pong game where my game is working 85% of the time, the ball is acting very strange, sometime the collisions between the ball and players are very weird. So I'm trying to understand what is going on.
The game is 3D with gravity.
I attached the image with code collision between players and the ball, I also added to drawline in debug to see the direction after the colision and... is very weird also.

I can show via streaming if you want.

[radiant coral]

Hey everyone! I'm using fixed joints to pick up gameobjects, and for some reason they're really jittery when picked up. I'm jointing the gameobjects to a child of my player camera. Anything I can do to fix this?
https://gyazo.com/ed9ce6623d6975a5da3cbec6b7670e9d

[timid dove]

Enable interpolation on the Rigidbody

[radiant coral]

Didn't work. Set interpolate to interpolate on the gameobjects, however they're still jittery.

It is actually a bit smoother than before, however it's still buggy when the player moves while holding an object.

[timid dove]

How's your camera/ player moving?

[radiant coral]

The camera is a child of the player, I'm not sure exactly how the player moves since I'm using the super character controller from the asset store. The player's rigidbody is set to interpolate as well.

[marble girder]

I'm a noob so take this with a grain of salt. Would it improve things to make the object a child of the player rather than the camera?

[radiant coral]

I'm not parenting the objects to anything, I'm using fixed joints to attach them to a child of the camera. Making that child a parent of the player wouldn't work as it wouldn't rotate with the camera.

[marble girder]

I see

[visual karma]

so i have a player & a ball, and i want the player to catch the ball and make it basically part of the player after catching

the thing is, often when the collision happens the player gets knockback from the ball

how do i make it so that the player doesn't receive any knockback from the ball?

[steel pewter]

I would probably store the players velocity, and when it collides with the ball set the player's velocity to what it was before the collision

[visual karma]

how would i store the player's velocity?

would getting it in OnCollisionEnter be too late?

[steel pewter]

I was actually looking at this earlier https://docs.unity3d.com/Manual/ExecutionOrder.html

[steel pewter]

get the player's rigidbody, use can use rigidbody.velocity. to read and store it

[visual karma]

well yes

should i constantly update it?

in FixedUpdate

or should i read it right before OnCollisionEnter

[steel pewter]

I personally would try storing it in FixedUpdate, then checking in OnCollision if you should reset the velocity to what it was last frame... seems kind of hacky on second thought, but it may work

[visual karma]

oh wow

it actually works

tysm!

[steel pewter]

Anyone experienced with angular velocity and torque?

I have a few spheres that are connected to weapons of various masses via a connected joint.

The angular velocity maximum is set way up, so ideally they'd be spinning really faster after a while.

Problem is though that the heavier weapons never get to full speed.... Is this just a misunderstanding of fundamental physics on my part? Or is it configured incorrectly?

Ideally the weapons (regardless of mass) will eventually get up to maximum speed.

Been stuck on this, would love any help

[torpid marten]

Good day everyone, I have a small little issue on a project, I imagine the solution is not very complicated but I could not for the life of me find a solution online...
TLDR is I want to make one of two rigidbodys not be effected by the other one, imagine controlling a tank that can push other cars around but no matter what, the cars cannot move the tank.
Physics Ignore doesn't work, as this would disable any collision at all.

[timid dove]

what is your joint configuration that should be causing them to spin?

[split solar]

Anyone know why my unity would fail a license check immediately after succeeding a license check?

Oh. Looks like my phone was viewing the physics channel the last time I was here. My bad.

[stuck bay]

target velocity doesnt affect anything, am i doing something wrong

there is no rigidbody attached

[dapper eagle]

Can i give a character/object 2 colliders 1 for the environment and 1 for other characters so that i have a sphere for the movement but it has a smaller collider for bumping into other characters?

I was thinking of layers

[timid dove]

yep just give it two colliders on different layers and use layer-based-collision matrix to set up the collisions

[dapper eagle]

Yeah, i feel like actually doing this can make some great things i always hesitated trying to just use a sphere for things like animals but i think it's a great option when using layers for other characters to not bump into the sphere but a smaller collider on the animal

[visual karma]

how do i make it so that

an object only responds to gravity

[wooden jacinth]

what do you mean "only" ?

[visual karma]

2 reqs

1. things bounce off it (i.e. it has a phys material on it)
2. the only movement it has is bc of gravity- it can't receive knockback from other entities & whatnot

[rare dove]

well would it be an option to simply move the object with translate rather than with a rigidbody?

[visual karma]

isn't it kinda bad to move RBs with translate

[quartz pagoda]

curious. Is the built in 2d physics limiting. Is there like a goto asset extension "people" use. Want to create a puzzle 2d game where you build your level with different props and then play out a simulation.

Almost worked exclusively in 3d before

[jovial wraith]

2d physics would work just fine for what you're describing. It'll feel more or less the same as working with 3d physics.

[quartz pagoda]

thanks. I will give it a shot! Cool to learn some new stuff

[cold socket]

Is there a difference between AddForce() with ForceMode.VelocityChange and just setting the velocity of an object?

from what I understand setting the velocity of an object skips some physics stuff.

after some further reading it just seems like AddForce() multiplies with mass, while velocity doesn't. I'll believe this unless someone else has other information.

[dapper eagle]

This is the correct info, a normal Force uses an actual force in Newton and VelocityChange i think is just in m/s

so if you want to control the speed yourself without figuring out all the forces you can use velocity change

[cold socket]

alright, great. Thank you!

[vale stream]

This probably has been asked before

But in a rigidbody based character controller

How do you cancel out any forces once none of the movement keys are pressed?

[stuck bay]

rigidbody.velocity=new Vector3(0,0,0);
i didnt try it

[vale stream]

My character controller uses addforces to smoothly speed up when a button is pressed in a given direction

How do i make it so that when no keys are pressed, it add a force opposite of the current velocity to slow it down smoothly

[stuck bay]

increase the 'drag' in rigidbody component to slow down faster

[vale stream]

What if i only want it slow down when on ground?

Do i just add a ground check?

[stuck bay]

you can do that

or add friction 'material'

[lunar lance]

my character controller got pushed by a navmesh ai agent through a wall. how do i fix it?

i've made the wall thicker and it just got pushed inside the wall instead

[clever cape]

Hey has someone a funny Shooter Game with funny phisics do Where the Player Can Push his with a gun in the air

[carmine basin]

ah, i understand what you meant with funny physics in the other channel now. It'd be quite easy. You just use the opposite of the barrel's forward as the force direction on the player

[clever cape]

Oh ty

Have u an Example?

[carmine basin]

I won't give you all of it, but i'll make it somewhat easier

you'd do something along the lines of

playerRigidbody.AddForce(gun.barrel.forward- * force)

[clever cape]

Im Not good in unity xD

So i want learn it

Learn

[carmine basin]

there's lots of tutorials online, as well as the official documentation

and you can always learn by experimenting too, as I did

[clever cape]

Ty very much

I will Show u my process Ehen im done 😁

[elder dune]

Hi, I'm currently doing a top down thirdperson controller using the Character Controller component and by moving it with Move() function and i want to add root motions to my movement for attacks animations.
The problem of course is that after the end of the animation, the player position go back to his initial state and the camera is not following him nether.

// I also wanted to use that kind of method for the dash animation but i ended doing a Coroutine where the player go forward but in that case, the player can go threw walls and thats why i check with a raycast if there is a wall but it doesn't work everytime ( check in fixedupdate + OnTriggerEnter lol )
My current method 🙁 :

[bronze sapphire]

I'm making pong game, I have a trigger collider on the rackets (rb2d kinematic) to return the ball ( OnTriggerEnter2D). I also have walls (with just a collider2d) that the racket shouldn't go through. I'm guessing it's a bad practice to have 2 different colliders on one object? What is an elegant way to prevent the rackets going past the walls? I'd rather avoid having to program this manually.
https://gdl.space/wosaxaveni.cs Code for the ball.

[carmine basin]

It's not bad practice to have two colliders on one object

At least, I don't think i've seen anyone say it is

I'm guessing its a collider set to trigger and a regular collider?

With your ball script, i dont think there's any need to call SyncTransforms

If you give me 30 seconds, I can think of something that might neaten up your script a lot in general

If you create a variable that holds the rigidbody of the ball, you don't have to keep calling GetComponent

With your initial problem though - its not an issue having two colliders on your racket

It sounds like because your rackets are kinematic, they don't respond when they hit something but other things would, like the ball

so the ball would bounce off it, but the rackets wouldn't stop moving when they hit the walls

I think you may be better off coding the position limit on the rackets

[bronze sapphire]

@carmine basin the issue I have is that I have a collider for the racket to trigger when it gets hit with the ball, I've created another thinner capsule collider (so that it's not triggered when it's the ball). This seems to work for me but not for the CPU - it goes straight through the top/bottom walls.

[carmine basin]

How are you controlling the rackets?

Do you use the velocity or do you translate them?

[carmine basin]

Do you change the velocity of the rackets to move them or do you change their position directly?

[bronze sapphire]

https://gdl.space/ulusiyomek.cs CPU

https://gdl.space/ovepanoxuq.cs Player

[carmine basin]

That's what's going on. You're translating the CPU while you as the player are moving with velocity

It might be overkill for this situation but take a look at something called a PID controller. It's some maths black magic thing I don't understand, but if you use the output from a PID Controller to control the y velocity of the CPU, you should get the desired behaviour

https://www.youtube.com/watch?v=roxhVW3KeRY&t=145s

This might be helpful for you

[bronze sapphire]

the collision detection doesn't work with translating the position?

[carmine basin]

I'm not entirely sure why collision isn't working with translation

It could be because its updating the position every frame or fixed update as it's also performing all of the physics updates

also

 if (!(_dist > 0.0005)) return;

what does this line do?

is that just checking the ball isn't too close?

[bronze sapphire]

yeah, it's to prevent small up and down movement when CPU is tracking y pos of the ball

[carmine basin]

Ahh, I see

[bronze sapphire]

The issue I have with physics in general is that I don't know the easy way to make the movement smooth. With addForce I'm getting yoyo effect when it applies too much force to match the ball and then it adds opposite force and it will bounce of the walls.

[carmine basin]

That's where a PID controller comes into play

It uses some maths stuff to counteract that movement and you'd be able to directly modify the velocity of the CPU player

alternatively, you could try this (gimme a sec to type it and figure it out)

_y = transform.position.y - ball.transform.position.y * speed;
//Change the below for however you're handling your rigidbody
racketRigidbody.velocity = new Vector2(0, _y);

maybe something like this would work if you choose not to go with a pid controller

[bronze sapphire]

thanks, I'll look at this PID controller method.

[visual karma]

how do i make

one object act really bouncy with A

but not bounce off B

[woeful cave]

Anyone know why my ragdoll melts like this?

be sure to @ me if you know

[viral ginkgo]

@woeful cave I think you might have problem in your weight painting

around the abdomen area perhaps

[viral ginkgo]

You can get the collision forces in the OnCollisionEnter
And the you can amplify the forces in the same directions and on the same points

[viral ginkgo]

Vector3 targetPos;
public float pMultiplier, dMultiplier;
void Update(){
  Vector3 delta = targetPos - transform.position;
  Vector3 pForce = delta * pMultiplier * deltaTime; // for moving to target (causes oscillations if used alone)
  Vector3 dForce = -velocity * dMultiplier * deltaTime; // for dampening the oscillations
  rb.AddForce(pForce + dForce);
}

simple PD control example here

[woeful cave]

I'll take a lil lookie, thanks

[visual karma]

it isn't possible with only physics materials & whatnot?

[viral ginkgo]

@visual karma You could have a different collider to collide with A and another one to collide with B

You could adjust their layers

And do the collision matrix

[visual karma]

oh wow

[viral ginkgo]

And that should work

[visual karma]

that's really big brain

tysm!

[viral ginkgo]

no probs

[visual karma]

hold on

how do you have two colliders on diff layers?

[viral ginkgo]

ball : rigidbody
colliderA : collider with bouncy layer and physics material
colliderB : collider with default layer

@visual karma

[visual karma]

you had to do that

the only way to

[viral ginkgo]

you add the colliders as childs

[visual karma]

yeah

that's what i thought

[magic crow]

hey everyone

I'd like some help if possible - I have a car game I was working on a couple of years ago, and I've dusted it off to play around some more

I have a rigidbody that I'm moving around with AddForceAtPosition. All works fine and dandy, but I'd like to add a lerp function to it to simulate drift

but I'm not quite sure how to add the lerp to it. Can I just do RB.AddForceAtPosition.Lerp()?

and add everything in the parentheses?

I've tried calculating the Lerp seperately and inputting it, but it's not working. It's annoying, but I've forgotten a lot in the time the project has been dormant

[magic crow]

is this the best place to ask you think?

[snow pebble]

Why is my fixed joint stuttering behind when connecting a dynamic rigidbody to a kinematic one?

[wispy patrol]

Can someone help me get my car to move?

I have some scripts for it, and wheel colliders, but they're still not moving

[magic crow]

I can try to help

can you take a screenshot of the code or something?

[wispy patrol]

@magic crow Whatever is easier for you. I took the code from a Youtube channel.

!pastebin

https://www.toptal.com/developers/hastebin/ebocumuten.csharp

Here is my car:

[magic crow]

damn. I just took a look, but that's so different to mine, I'm not sure what's going on. I guess what I'd do is start putting debugs in to figure out what values you're getting. Also make sure that the controller is set up within Unity - I remember I had a problem with that early on. Hopefully someone else can help you.

[wispy patrol]

Thanks for trying @magic crow 🙂 ❤️

I don't even know if the script I used is ideal. I'd like to use whatever is the standard and is modern

[snow pebble]

Is there any way I can set the velocity of a kinematic rigidbody without it automatically going back to zero?

Setting it in late update seems to work.

[wooden jacinth]

Quick question, I had a rigidbody which i tried to stop, i reset the velocity, i reset the position, i put the rigidbody to kinematic, i change the parent, i change the localposition, but if the interpolation mode is in "Interpolate", my rigidbody wasn't following the parent like it should have, if its set to No interpolation, it works fine, I'm not sure I understand the reason, any guess?

video clip if that can help understand lol https://clips.twitch.tv/AlluringSpookyOilHassanChop-DlFKYkny1FwJSRKg

[snow pebble]

Because that's what interpolate does, instead of going to the target on the next update, it only goes part way. You can think of it like a lerp function that is applied to the object between it's previous position and the position you want it to be. Unless there's some reason you want to keep the interpolation I wouldn't use it for this case.

With the snappy transformative nature of a kinematic body this issue would probably just become more prevalent.

[wooden jacinth]

Ok thanks for the details

[snow pebble]

np

[wooden jay]

Anyone got any advice on how to improve the determinism of the PhysX engine?
My current instant replay system doesn't have the most accurate results (they don't have to be perfect just good enough to look almost identical once interpolated a little)

Current Physics settings:

[mossy iron]

Noob question: my player has a dynamic simulated RigidBody2d, and I have a box with a BoxCollider2D with is trigger checked. why isn't OnTriggerEnter2D being called when my player enters the box? anyone have ideas?

[wooden jay]

alyways fingured it was done when simulation was called, but prob not

[wooden jay]

How are your layers setup? double check spelling and make sure the OnTriggerEnter2D has the correct parameters

[wooden jacinth]

does your player have a collider that is not trigger?

[mossy iron]

I'm a dumbass. Turns out I was calling OnTriggerEnter instead of OnTriggerEnter2D. 🥴

[wooden jay]

It's programming. Everyone makes dumbass mistakes. It's part of the job (I spent 3 hours trying to debug an issues for why my script was having wild results, turns out I didn't start my index at 1 like I should have lmao)

[magic crow]

just wondering if anyone can help me using lerp and addForceAtPosition together?

[magic crow]

Figured it out. Should have followed my own advice and debugged some variables

[real belfry]

i'm currently doing a bullet-like projectile but I don't get it why this sphere goes up and down lol

I used addforce on it btw

[viral ginkgo]

@real belfry looks like your models pivot is shifted

[real belfry]

I used an empty object and it instatiates the ball prefab

[viral ginkgo]

@real belfry Maybe you have a rigidbody parented to another rigidbody?

[real belfry]

okay let me check it cuz I put my empty gameobject(spawner) as a child for my cannon prefab lol

@viral ginkgo welp it still moves weirdly

[viral ginkgo]

@real belfry Well its gotta be something in the hierarchy of the ball

[wispy patrol]

What kind of joint should I use for a car?

[sudden flame]

Hi. Is there any way to remove like the air friction while still being kinematic please?

Like, I have a lever inside a car, but when the car moves, the level rotates according to its inertia, and I would like to eliminate that inertia if it's possible

[wooden jay]

Set the localPosition of the ball prefab to zero after it's been parented to the empty GameObject

[wooden jay]

Remove the Rigidbody component. If its only function is a lever, I doubt you need physics for it

[wooden jay]

For like what? The wheels? Either the WheelCollider or a SpringJoint for custom wheels

[wispy patrol]

Oh, so if I use wheel collider I don't need a joint?

[wooden jay]

Nope! It's got one built right in. The wheels will need a bit of tuning, so make sure to read guides on friction, suspension, etc

[wispy patrol]

Thank you!!

[clever cape]

Haha Same that Happens me too 🤣

[sudden flame]

Yeah I think I would need it because it works with a hinge joint, that's the problem

[wispy patrol]

But it looks fine in the scene view

[wispy patrol]

Anyone have an idea why my wheels are flat:
don't know why but my wheels are looking like this:
changing the rotations doesn't help

But it looks fine in the scene view

https://media.discordapp.net/attachments/580995273325543434/990619649332883516/unknown.png

[versed blaze]

I am having difficulties connecting the parts of my tank with joints, centers of rotation are off, and sometimes the parts of my model become disjointed (https://stackoverflow.com/questions/72763583/good-way-to-animate-a-tank-with-joints-in-unity), anyone good with joints round here?

[visual karma]

do i apply a phys material to the collider or to the rb?

[unique cave]

have you tried both? rb doesn't have slot for phys material

[visual karma]

?

[unique cave]

oh, that's rb2d (regular 3d rb doesn't have that)

[unique cave]

The PhysicsMaterial2D that is applied to all Collider2D attached to this Rigidbody2D
so use that if you want the same material to apply on all colliders of the rb2d

[visual karma]

icic

[lilac patrol]

anyone know why RigidbodyConstraints2D.FreezeAll resets the rotation of the transform?

[unique cave]

What you mean by that?

[lilac patrol]

never mind, it was an issue in my code

[polar nexus]

I have this issue that if I enabled = true or even wc.gameObject.setActive(true) a Wheel Collider it seems to freeze my rigidbody for one frame. Has anybody run into this issue and managed to solve it? (Unity 2021.1.25f1)

[timid dove]

Disabling the collider probably forces the Rigidbody to recalculate it's center of mass and resets its velocity and angular velocity in the process.

Should be a simple enough fix. Just record velocity and angular velocity before doing it and set them back after

[polar nexus]

yeah ok thanks I was afraid of that, not a pretty fix, but i'll have to do

[timid dove]

Wrap it in a function and forget about it

[wooden jay]

Do you still need help?

[vital loom]

I have a question about configurable joints. I want these joints to follow each other closely with a small margin of deformation. When i set linear limit to 0, there is no deformation, when i set it to a small number (.000001) the joints allow for large amounts of deformation and only slowly move together. Anyone know why? resources on these joints would be appricated

[wispy patrol]

I do! 🙂

[wooden jay]

How are you updating the visuals of your wheels? Every FixedUpdate you should be setting the rotation, and position of your wheel visuals. This is what I do:

  collider.GetWorldPose(out Vector3 position, out Quaternion rotation);

  colliderTransform.rotation = rotation;
  colliderTransform.position = position;
  colliderTransform.localRotation *= Quaternion.Euler(allRotationOffsets[i]);

colliderTransform is the transform of the wheel visuals, collider is the actual WheelCollider component

[wispy patrol]

Gotcha

[wooden jay]

allRotationOffsets is just an array of Vector3s that map to the wheels, which I change as desired

[wispy patrol]

I have something similar

minus setting the localRotation

[wooden jay]

I think you need to set the localRotation then. Setting the world rotation of the transform just makes sure it's rotating correctly, while setting the localRotation *= Quaternion.Euler(allRotationOffsets[i]) corrects for miss-rotated wheel visuals.

[wispy patrol]

@wooden jay For allRotationOffsets , do I need to use the rotation property of the wheel transform?

[wooden jay]

It sets the localRotation of the colliderTransform that is the actual visible wheel. I have it setup a bit different then you likely. Instead of a single GameObject that has the WheelCollider component, scripts, MeshRenderers, MeshFilters, etc its actually setup: WheelVisuals that is a child of the WheelCollider that is a child of the RootVehicleBody GameObject

the wheel visuals and wheelcollider is not a single gameobject, but 4 gameobjects (or however many wheels you have)

[wispy patrol]

@wooden jay My meshes are children of my wheel colliders

and my wheels colliders are children of the rootvehiclebody

[wooden jay]

It's setup just like how I have it then. The colliderTransform is the transform of the meshes (I actually need to rename it to wheelVisualsTransform but haven't gotten around to it)

[wispy patrol]

That's my error message

[wooden jay]

your assigning it to the localPosition not localRotation

also, it looks like your IDE isnt setup because intellisense should flag that as an error in your IDE (VS Code, Visual Studios, Rider, etc)

[wispy patrol]

Oh oops, I thought I had it

I'm nto familair with it

I'm still getting the same error message though

[wooden jay]

Quaterion.Euler() takes a Vector3

[wooden jay]

replace the wheel.transform.rotation inside of the Quaterion.Euler() method with a public or [SerializeField] Vector3 field that you will adjust in the inspector

[wispy patrol]

Yayyy, you did it! 🙂

[wooden jay]

Glad it works now 😄

[wispy patrol]

Thank you so much! ❤️

[wooden jay]

np 👍

[wooden jay]

@prime flower holy shit just ran a 5 min replay using only physics (Velocity, angularVelocity, AddForce, and AddTorque) and it ended up being more accurate than I though. There were planes that were inverted that causes weird corrections, so Im going to test without them now

[wooden jay]

yeah, way more accurate. Plus I did a replay only using AddForce and I couldnt tell the difference either

[harsh glacier]

Hi, I want to make a radio antenna (like the ones on tanks). I have tried messing around with hinge joints but I have been unsuccessful. I have tried implementing the first answer, can anyone guide me in the right direction here? My plan is to connect the hinge joints to bones of a mesh. https://forum.unity.com/threads/antenna-for-a-remote-controled-tank.38806/

[dawn elbow]

Could someone point me to the right terminology for this…

I am creating a VR game that has a constrained path but requires the ability to move the character both left right and up to dodge objects.

Could someone please direct me to the right feature to look into?
I looked into waypoints but this seems to have limitations(?)

[timid dove]

splines

Luckily Unity has recently released a spline package! https://docs.unity3d.com/Packages/com.unity.splines@2.0/manual/getting-started-with-splines.html

[dawn elbow]

Thank you so so much

[acoustic jasper]

Is there a way to make raycasts/colliders more reliable? I find that sometimes the results can vary depending on the system and FPS. I have a mario-like game and sometimes the player will stomp on the enemy, and sometimes the player will take damage instead of stomping.

[bleak umbra]

they are reliable if you use them correctly and understand the inaccuracies inherent to the physics system. The most critical thing to watch out for is to make sure there always is sufficient room between your ray's origin and the collider you try to hit. At sufficiently high velocities your rays can easily miss a collider if they are too short.

[viral ginkgo]

I think you should be fine enough if you don't rely on rigidbody collisions

Maybe you can just work with trigger colliders
If you need, there should be an option in the physics settings to make raycasts hit trigger colliders

[harsh glacier]

Hello. I have a two hinge joints set up. I want to know how to allow the hinge to have an effect in all directions. I would also like to know why the top cube moves on the x axis. The hinge joint is set to the x axis.

First cube Hinge setup:

second (top) cube hinge setup:

[radiant coral]

Hey everyone.
I'm trying to create a mechanic for my first person game, which allows the player to be able to drag certain objects (most notably vehicles) around. I haven't been able to find anything online about this, so I was wondering how I should go about this?

For example:
I want the player to be able to click and drag the point marked in red, which would then make the trailer move along with that point.

[timid dove]

uisually you would do something like this:

• When the player clicks you create or activate an invisible kinematic Rigidbody at that position
• Attach the wagon to the invisible body via a physics joint
• As the player moves the mouse, you move that Rigidbody via Rigidbody.MovePosition to the mouse position in FixedUpdate

when you release, you can detach the joint/destroy/deactivate the invisible body

[timid dove]

How are you rotating the wheels? @sterile light
How are they connected to the bot?

[sterile light]

Each module is a child of the module it's connected too, so the wheels children of the main computer module in the middle (which contains the rigidbody)

[sterile light]

The wheels are connected to a rotator module, which rotates using transform.rotation during fixed update
(and sorry for the late reply, I never got the ping notification)

[timid dove]

well that's why

you're rotating via the Transform

you can't directly modify Transforms if you want physics stuff to work

Rotate it via:

• AddTorque
• setting its AngularVelocity
• MoveRotation

which are all related to the Rigidbody

not the Transform

[sterile light]

I assumed that was the issue, but since the wheels don't have rigidbodies on them I wasn't sure how to do that

[timid dove]

they need Rigidbodies

[sterile light]

would it be better to put a rigidbody on every module?

gotcha

[timid dove]

Rigidbodies are the basic building block of the physics engine

anything you want simulated by the physics engine needs one

I get what you did though - the root probably has a Rigidbody right?

And the wheels just had colliders?

[sterile light]

Right... but then when I put rigidbodies on each module my robot falls apart, since the parent rigidbody is using a compound collider, and joints don't hold it together properly

yeah

[timid dove]

For something like this you'll need separate Rigidbodies

and connect them via physics joints

[sterile light]

I tried that before and the joints were super wobbly, even the 'fixed' joints, and i couldn't really find a fix for that

[timid dove]

it's all about the settings on the joints

You could also look into Articulation Bodies

[sterile light]

Okay, I'll look at this right now ^^

thank you

oh, and should my child rigidbodies be kinematic, if I take that route?

I kind've want them to be affected by everything so I assume the answer is no

but I also want the robot to act as one more-or-less solid piece of metal

so.. maybe? idk

[timid dove]

if you want this - just use one RIgidbody on the root of the robot

you can have as many colliders as you want on child objects

[sterile light]

yeah that’s how I’ve got it now, it just doesn’t rotate with wheels or anything

[marble blade]

Working on a simple flight simulation, I try to figure out how to compute a believable pitching moment.

I already got a decent lift and drag dependent of the wing span/area and the angle of attack, and now I would like my aircraft to naturally pitch down at low speed, or up when rolling, but I can't find the good math.

I'm not using control surfaces, only a general wing physics approximation.

Anybody has experienced with it?

[bleak umbra]

make the plane balanced at rest, add a upward force at the tail that tapers off to zero with speed, or implement is like in reality, nose-heavy rigidbody with a compensating force that balances out at the ideal airspeed

guess you can't really have believable nose pitch/balance without trim

[unique cave]

Are they dynamic or static (do they have rigidbody)? How many of those objects you have?

And do you know if the lags happen only because you move them or is there some collision checks involved (in case of dynamic rigidbodies)?

[empty schooner]

I posted this in the wrong channel first, but now here I am. How expensive are rigidbodies when collision detection is set to Discrete and the objects are on a separate layer, not colliding with anything? I am toying with the idea of changing my damage numbers (that currently float upwards and fade) to a more fun physics based mechanism. So they'd plop out the top of enemies heads to the left and right. Again, they wouldn't collide with anything (not even the ground), but I want to avoid anything that adds any kind of extra performance hit.

[wheat jasper]

my car is shaking and i dont know why. i searched the internet and nothing helped me. i am using wheel colliders.

[empty schooner]

Just a guess, but you have a box collider covering the entire car. Both the cars box collider and the wheel colliders are not triggers and they're on the same layer (edit: layer, not level). Which means you have colliders overlapping, that are colliding with each other. Imagine having a wooden block the size of the car (your box collider) and then the four rubber wheels occupying the same space.

Either give the car a separate collider (or separate colliders) that don't overlap with the wheels, or for a test simply make the cars box collider a trigger (is trigger = true). I'm not sure if that's the issue, but overlapping colliders that collide with each other is definitely not something you want.

[timid dove]

If there's only one Rigidbody, collider overlaps won't matter, as they're all part of the same body

[carmine basin]

Try adding the suspension to the wheel colliders. that should dampen the forces a bit

[wheat jasper]

i will try

this?

[wind nebula]

Is a capsule2D more efficient than a box2D shape?

[tardy arch]

idk if this is the right place to ask this but how can i keep my fps camera from clipping the head of the player? Is there a way to make the mesh invisible for just the fps camera? Any help is appreciated, thanks!

[unique cave]

Yes, capsule is simpler shape mathematically (2 points and radius). Circle is even simpler (point and radius). The difference in performance isnt massive tho

[kindred quail]

Does anyone know why CheckSphere only works with convex mesh colliders?

[unique cave]

Im not able to find anything about that on google so most likely it should work. Theres probably something other wrong in your code or colliders

[timid dove]

it should work fine with concave colliders

[stuck bay]

question about performance related to collisions;
i have a few hundred objects in the scene which can be picked up and thrown around by the player. If i had a script attached to each of those objects to listen for collisions, how performance heavy would it be? is there better ways to listen for many collisions at the same time?

[timid dove]

try it and see

the scripts being attached won't really affect the performance, except when it actually runs/gets triggered

[bronze whale]

Which settings should I change (and how should I change them) for unity WheelColliders to reduce understeer & prevent the wheels from lifting up in high-speed corners

[dapper eagle]

I have a layer (6) that i wanted to store in my code i know it never changes so i can directly set it in code but i forgot the way it was done

i think you had to use an operator or something or can i just do Layermask thisLayer = 6;?

[median lava]

Does anyone know anything about issues with Physics.SphereCast? They've been mostly working for me, but in some cases they end up generating incorrect collisions. I've only noticed it when the spherecast is close to parallel with the wall it collides with, and the collision is later than it should be. Here's an example of a sphere and its returned collision point (in green). The sphere has clipped into the wall significantly, and should have collided with the wall a full sphere width further away from the camera, where it was coming from.

I can perform a Physics.Raycast or a Physics.OverlapSphere earlier along the path of the sphere and both confirm that a collision should have occurred earlier. Is there some resolution setting or something similar I should be tweaking to get better precision here, or is Spherecast specifically just not fully accurate?

[median lava]

Found a few forum threads with similar issues but no one with any workarounds. I'm guessing I'm just out of luck at this point but if anyone's got ideas I'm happy to try them.

[timid dove]

The details of your sphere casting may matter here. Are you doing this as a custom continuous collision detection approach?

[stable gulch]

Hi guys. Maybe someone who has more exp with Unity joints, can help me out here > https://forum.unity.com/threads/why-is-a-configurable-joint-moving-both-parts.1303605/

[median lava]

More or less, yeah. I'm doing it to predict when and where a launched spherical object will land before it's launched.

It may sound like a bit of clipping isn't a big deal, but here's an example of how it really messes things up. If we pick the same starting point A for the cast as in the above picture but only cast the sphere to where the actual collision should happen (point B) instead of all the way to the incorrect collision, sphere cast will say there wasn't any collision at all. However, any future spherecasts from point B will ignore the mesh collider entirely, since it starts within the bounds of the initial sphere because there should have been a collision. That means it's possible to perform a spherecast from point A to point B, and then another from point B to point C, and get no collisions returned even if there is a solid wall between A and C.

[stable gulch]

Updated the post to make the question more clear 🙂

[timid dove]

yeah that "doesn't detect things it starts inside" behavior is exactly what I was worried about, Is there any chance the object you are trying to detect is moving?

[median lava]

I've confirmed that at point A Physics.OverlapSphere doesn't return any results, and it does return results at point B. The MeshCollider in question doesn't ever move.

[median lava]

Also note that casting from A in the direction of B, but with a long distance, it does generate a collision with the meshcollider, just the wrong one further away from where first contact is actually made. Since it can generate a collision with a longer distance, it seems pretty clear that it's not excluding the meshcollider from the search in the initial A to B spherecast, only the B to C one.

[strong shadow]

I'm trying to use a wheel collider but the collider does not show up. I have rigidbody on its ancestor and gizmos should be turned on. Is there any other way to fix this issue?

[timid dove]

Double click the object that has the collider and make sure you haven't disabled that specific Gizmo

[modest cairn]

boys, when sometimes my object are moving a bit fast, they seem to clip or pass through other objects
anyway to avoid this ?
perhaps another method of movement ?
would like to hear ur opinions about it

[lapis plaza]

CCD

[modest cairn]

Much appreciated !

[modest cairn]

a random question that I was thinking of, when using AddForce, is there a way to make it limited to a certain speed ?

[stable gulch]

what kind of force?

There are 4 modes

[lapis plaza]

I don't even understand the question.. you can do your own velocity check prior applying addforce

[unique cave]

Can you just clamp the magnitude of rb.velocity after that? Or do you want this particular force to have no effect after certain speed or?

[lapis plaza]

basically we are just guessing here what the end goal is so it's pretty hard to make suggestions

[modest cairn]

well, it's basically to set a speed limit, in a way

the reason why I guess I am asking is, I want the object to reach max velocity as soon as possible, but then cross that final speed no more

so, I guess you could say clamp the magnitude of rb.velocity after that amount of speed

[lapis plaza]

still wondering what the end application is.. like is this for limiting vehicle's max speed or something like that?

[modest cairn]

yep, limiting the vehicle's max speed

[lapis plaza]

you could do it the hacky way like that

[stable gulch]

Well in real life a motor can produce as much as force as it can. Maybe you should also find some sweet spot, that doesnt make it to fast

[lapis plaza]

or do it properly by computing the aero drag

[modest cairn]

well, my project isn't anything big, so I am fine with a hacky way to do it

is there like a maxLength() method like with strings, but with velocity ?

[lapis plaza]

magnitude

or length

but I'm going to assume unity's vector math lib uses magnitude

[modest cairn]

magnitude, that maxLength() was merely an example of something similar for strings

[unique cave]

Theres Vector3.ClampMagnitude

[modest cairn]

hmm, interesting

so, by also adding velocity I could also clamp it ?

or do add a new line of code where rb.velocity = vector3.ClampMagnitude( some number ); ?

[lapis plaza]

that aero drag isn't horribly complicated to do either

it's essentially just this

[unique cave]

You need to put in two arguments, vector to clamp and max magnitude (max speed)

[lapis plaza]

where after constants being out of the way, you just have velocity ^2 multiplied by a constant and that's your counterforce

it's really simple in the end

[modest cairn]

hmm, seems interesting

I will try these out boys, thank you both

guess I needed those math classes after all xD

[stable gulch]

Can someone explain ArticulationBody.driveForce? It returns ArticulationReducedSpace which is really never explained properly.

[keen siren]

i have one last thing got a sword which is my hand model which is also a fbx but i need to add collider to it when i do it dosent show up can anyone possibly help? (3d )

[stable gulch]

nvm

[warm pilot]

i'm working in 2021.3. can someone please explain to me ArticulationBody.SetDriveTargets?

it says Assigns articulation body joint drive targets for the entire hierarchy of bodies.

Number of degrees of freedom(DOF) for the articulation body can be found using ArticulationBody.dofCount.

so i call rootObject.dofCount and i get zero.

and i know I set all the joints to be at least one degree. if I call dofCount on each joint separately I get 1

so something is wonky here

[hard jacinth]

why it go scrunchy?

[karmic leaf]

is it possible to have both animation and rigid bodies at the same time?
for example maybe for example maybe i animate a character but i still want to give it rigid body physics so it can react when the character gets hit by a sword or crushed by a large object

[unique cave]

You could use the animation but enable the ragdoll/rigidbodies after its hit by something

[green thistle]

Hello, I would to do a simulation of a car based on a trajectory i will have set( e.g from skidmarks and speeds) do you have any tips. tutorials?

[last halo]

Hello. i want to move an object at a speed of n M/S using rigid.addforce(Forcemode Impulse), anyone got some tips to make this happen for me

its a bullet from a gun, but when i put real numbers like 660 to the addforce amount it comes up so slow until i put something like 35000 then it kinda makes sense ... What do i do

[unique cave]

Maybe the mass of bullet is wrong or youre using wrong forcemode. Why dont you use rb.velocity?

[last halo]

For bullet ???

[unique cave]

When shooting? Why not?

[last halo]

mhh interesting

how do i do it

what about the bullet drop and all the other stuff, or do i just tell it once when the bullet has spawned

[unique cave]

Yes, you tell it once and physics system takes care of rest

[last halo]

U might be right here coz i wasnt using any force mode

it was like Bullet.AddRelativeForce(new Vector3(0, 0, Stats.MuzzleVelocity));

now i changed it to Bullet.AddRelativeForce(new Vector3(0, 0, Stats.MuzzleVelocity), ForceMode.Impulse);

Or wat forcemode would you recommend coz i have read all four of them and i dont understand $%^$

[unique cave]

Youre using Force by default. But why are you using force to begin with if you want to give certain velocity?

[timid dove]

Just set the velocity directly if that's what you want

bullet.velocity = direction.normalized * desiredSpeed;```

[karmic leaf]

How could I go about doing that? I'm stull new a bit new to both unity and rididbodies

[warm pilot]

anyone here familiar with ArticulationBody? I have several questions and the API is poorly documented.

The drive will apply force to the body that is calculated from the current value of the drive, using this formula: F = stiffness * (currentPosition - target) - damping * (currentVelocity - targetVelocity)
ok first off that seems backwards, it should be target-currentPosition.

[unique cave]

Do you have the ragdoll physics working for the character already

[warm pilot]

@karmic leaf https://www.youtube.com/watch?v=oVPI2ESkgIw

[karmic leaf]

ay thank you!

[karmic leaf]

not yet, but im going to first watch the video robots sent to me

[last halo]

@timid dove & @unique cave all of these work the same and they work exactly the way i want. Thanks to you Guyz 🥳

This qn may not belong here but if I have weapon customization should i Spawn and Destroy attachments or just have them in the gun ready to enable them (using gameobject.setactive() ) . . .

[dense lintel]

I have a capsule object with 'Rigidbody 2D.' The tilemap is currently a floor of tiles with 'Tilemap Collider 2D.' I can't figure out why they aren't working together. Am I missing something?

Nevermind I forgot the gosh darn collider.

[unique cave]

Btw why are you getting the same component twice?

[last halo]

I know i could just get it once but idk why i didnt

wait getcomp<> uses alot of CPU right, wat am i doin .... this is bad practice. its a bad habbit i have to forget that code should also be optimised

[unique cave]

Nope, it doesnt use lot of anything. Just why to do same thing twice if one is enough. You can use get component 1000 times every frame and not notice any difference on framerate, its not that heavy at all. Use it when it makes sense. Instantiate is most likely taking much more time in this case but thats not that slow either

[last halo]

Yeah i saw a guy on YT who was just enabling and disabling attachments while i wad instantiating so that just got me thinking which one was better in terms of performance

but it just feels like its the same so i havent really bothered to change it

[unique cave]

Object pooling is better but dont bother now, optimize your code later if needed

[last halo]

funny story i dont know whay object pooling is OR how to do it

[unique cave]

Try to make everything functional first and do optimizations later if you have noticeable lag spikes etc.

[last halo]

huh ... OK

i was already googling object pooling

[unique cave]

Its good to know those concepts but you dont need to worry about optimization now. I dont think that code alone will cause any sort of performance issues. If you have 1000 of those running at the same time, then you probably need to do bit of profiling and see if you must do some optimizations, otherwise not

[last halo]

Thanks am watching brackeys XD

https://www.youtube.com/watch?v=tdSmKaJvCoA

[thick lantern]

Is there a good place to see values that work for Wheel Colliders <-> rigidbody?
I have tried a million different things but my car just keeps shaking like a chihuahua on a blender.

I have seen that a lot of tutorials on the internet use really small values (0.08) for wheel size, why is that?

[bleak umbra]

You can’t fix something that is inherent in the system. To fix shaking you’d increase the dampening power of the shock absorbers and balance that with the spring strength and car weight

[thick lantern]

Wheel colliders are broken?

[bleak umbra]

No magic values exist

[bleak umbra]

They are not broken, they are just wheels, you need to add shock absorbers to the driving model

[thick lantern]

never heard of those, but ill search for it

[bleak umbra]

Golden rule of physics sim in games: understand the real thing you are simulating.

[thick lantern]

Makes sense. I know what shock absorbers are in real life, but im testing this on a plane so I didnt think I'd need them. Also my shaking in in forward-backward, now up and down

[bleak umbra]

Would make for very difficult landing without them

[thick lantern]

a plane, as in, a plane floor, not a ✈️ :P

[bleak umbra]

Maybe you need to absorb floating point inaccuracies

But drag, friction and gravity should take care of those

[thick lantern]

I have a player separate from the car, but when sitting at the wheel, i make the player a child of the car. I thought that the problem could be of the camera, but parenting takes care of that right?

[bleak umbra]

It should

[thick lantern]

Yeah I just tested and left the car and it shaked even without me in it.

I didnt find any shock absorbers, but wheel colliders have those inherently right? The suspension distance + damping rate ? or is it a different thing?

[bleak umbra]

That’s the thing

[warm pilot]

how do i reset an ArticulatedBody to it's initial position? obviously it's more than just resetting the transform. I'm trying to reset a posable creature for ML training. My workaround has been to instantiate the prefab, play with that, and then destroy & reinstance at the next play-through. downside is I can't investigate the limb values because every new instance the heirarchy collapses in unity.

which is fair, and expected... and unfortunate.

[stuck bay]

my sphere keeps decelerating despite having zero drags and friction

how do i fix

oh its rotating, i dont know why

[stuck bay]

found the solution, which is to set "friction combine" to minimum in physics material

[warm pilot]

nice follow up 🙂

[hard jacinth]

why ragdoll break leg?

like there is a joint there but it seems to just think there isn't

outside of the ragdoll it works fine

[drifting sleet]

is there a way to make typical terrains behave less bumpy with wheel colliders

[keen siren]

So im dealing with a third person controller and am also not too well-versed in Quaternions, but why is it that Vector3.forward * Quaternion.Euler(0, targetAngle, 0) would produce an error of operand * cannot be applied to Vector3 and Quaternion, but if you reverse the math to Quaternion.Euler(0, targetAngle, 0) * Vector3.forward it works fine?

[bleak umbra]

because the multiplication of quaternions is not commutative, i.e. order matters

[keen siren]

okay that was an idea i had in mind, just couldnt think of the word. Appreciate it

[drifting sleet]

it's true that quaternion multiplication is not commutative. but like any operator, it's whatever the programmer wants it to be. you could define an operator *(Vector3 lhs, Quaternion rhs) that does the rotation, if you want. if you're asking why unity chose to define the operator the way they did, my guess - it can only really be a guess - is that rotating a vector with a quaternion is a matrix operation X Y where the sizes of the matrices are X=(3,3) and Y=(3,1). so there's only one order you can multiply the matrices validly. and they're leaning on the symbolism of the * as multiplication

[drifting sleet]

that's a pretty hilarious bug

[hard jacinth]

it is, but i solved it, the pivot was set to the wrong bone

[drifting sleet]

i think you should ticket it with unity to ask. that component exists for weird end user purposes

[drifting sleet]

the center of mass is wrong

you should use an asset. there's the car from standard assets, and also edy's vehicle physics, which is the car standard asset with lots of extras

[thick lantern]

I fixed it by making everything a lot smaller

idk why

all the numbers I saw on other things like this were really small, and it worked

didnt change the center of mass

[warm pilot]

oh? i've been using it with machine learning to teach a robot dog to walk. 😦

[drifting sleet]

yeah

go ahead and ticket somewhere

report a bug is a waste of time

but if there's a github repo associated with it (e.g. ml agents) try that

[warm pilot]

somewhere
aye, there's the rub.

[keen siren]

Great explanation appreciate it

[stark wagon]

Would anybody be willing to jump in a vc with me and explain some physics stuff?

I am so down bad with lerp

[fiery bolt]

How do I check if RaycastHit was a hit or not in code?

[ivory shadow]

anyone know how to addforce in the X direction? I did rb.AddForce in the jump but whenever I use it in theX it just snaps/teleports. Thanks

[supple sparrow]

You'll have better chances of an answer if you post here. Someone knowledgeable may read and answer. Or not !

[supple sparrow]

Physics.Raycast() and variants will return true on collision. Then you'll find the hit info in the out var. Check manual for an example

[supple sparrow]

Not sure without seeing code but probably you have some code elsewhere setting the transform ? You can't do both transform override and moving through forces

Those will conflict each other and you'll witness the snap/teleport

[ivory shadow]

thank you for the response, I did fix it already

apparently when I do not disable the gravity while AddForce at X has value, it just won't move on the x, unlike in the y

[twin quarry]

Hi, does somebody know if there is a way to get notified once the ContactPoints of a Collision update (2D)? I simply want an enemy to swap direction once he collides with a wall. However using OnCollisionEnter2D does not work for me, since I'm using composite colliders. So the wall is the same collider as the ground, and I only get one OnCollisionEnter2D for the ground, not when he collides with the wall. If not I will need to read the Contacts every physicsframe or do a Raycast.

[timid dove]

You can use OnCollisionStay2D

you will get a callback every physics frame

you can check the contact points every time

[untold loom]

Hello, I have a problem with collisions(triggering): When the weapon(the baseball bat) attacks then the enemy gets hit more than 1 time(so it gets more damage), because the enemy has many colliders attached. So it calls the method "Damage()" multiple times. I want to hit the enemy 1 time and call Damage() only 1 time. I added a collider on every bone

[timid dove]

What script is it calling Damage on?

some script on a parent of the colliders?

you can do something like:

HashSet<IDamageable> damagedThisFrame = new HashSet<IDamageable>();

void FixedUpdate() {
  damagedThisFrane.Clear();
}

void OnCollisionXXX(COllision other) {
  IDamageable c = other.collider.GetComponentInParent<IDamageable>();
  if (c != null && damagedThisFrame.Add(c)) {
    c.Damage();
  }
}```

this way you'll only damage the unit once per physics frame

[untold loom]

When I hit the a bone(the collider of the bone) then a script on the weapon searches for the root gameobject of the hitted collider. On the root gameobject is a script attached named IDamageable. Then this script calls Damage()

[timid dove]

yeah - track which IDamageables you've damaged this frame so you don't do it multiple times

though I guess this mihg tnot be sufficient because you could hit another bone of the same character the frame after in a single swing right?

So we can modify it a bit...

[untold loom]

yes

[timid dove]

~~Ok it's slightly tricky but something like this: https://gdl.space/ehemokucol.cs~~

[untold loom]

thx, I'll try

[timid dove]

Actually sorry - slight fix: https://gdl.space/umomatuqep.cs

[untold loom]

ok

[untold loom]

Same problem as before. It calls Damage everytime it collides with a bone/collider

No, I made a mistake. I works perfect thank you!!!

[woeful rapids]

I need to half the value of a Quaternion, but I can't figure out how to do this. Does anyone know how?

Context: I have 2 Quaternions, a and b. I get the difference between them, c by doing c = b * Quaternion.Inverse(a), and I want to add that difference (c) to a, halving c every frame, so that the rotation slows down over time.

[odd osprey]

Why does two of my objects collide on low speed, but they don't collide on higher speed?

One of them has Continious and the other one has Continious Dynamic Collision Detection

[odd osprey]

they just go through each other

Both of them has colliders and rigidbodies

[timid dove]

how are you moving them?

btw unless they're rotating, usually Continuous is the correct option

[odd osprey]

One of them is always rotating

And the other one is the player

The player is standing, and the rotating object goes through the player

Instead of pushing it away

[timid dove]

how is it rotating?

How does the player move?

I'm looking for you to be specific here. Like show code

[timid dove]

you're rotating directly via the Transform

that bypasses the physics engine

try:

rb.MoveRotation(rb.rotation * Quaternion.Euler(0, value * Time.fixedDeltaTime, 0));```

(where rb is the cylinder's rigidbody)

[odd osprey]

Well

this didn't go as expected

[timid dove]

is there a reason you're setting the position each time?

I think you should make the spinning bar kinematic

get rid of the position = line (line 19)

[odd osprey]

It works now

i got rid of the 19th line, and made them kinematic

thanks

[normal leaf]

I have a character with a cape and when I try painting constraints it doesn't work. Any ideas?

[lunar magnet]

how do i switch from featherstone solver to gauss sleidel solver

[stuck bay]

is there a a way to make the model collide with its instance, but not internally

[oblique cipher]

Y'all I know tons of people have solved this, but I don't see any definitive nor has anything worked for me yet.
The basic premise is. I have a sphere. I move it with force.
I have a few tiles, lined up using a the tilemap system's object brush (the tiles line up and are flush is what this is to say.)
When the ball rolls over a seam, the ball sometimes jumps.

I've tried the following: Using mesh combining scripts. Using the Mesh Combiner free asset (which is great). I've tried setting the ball from discrete to continuous, and continuous dynamic. The tiles just have a mesh and a mesh collider.

I've tried 2 different meshes, one that is "one sided" (not sure of the deffinition) and these which are full contained tiles. Both act the same way.

Anyone have any advice?

If it's any help this is using kenney.nl assets and the car controller from his patreon (with updates to use input system)

[storm drum]

I want to build my own custom collider shape in code, creating a new class that extends https://docs.unity3d.com/ScriptReference/Collider.html . Anyone know of any examples online that I can use for reference?

[storm drum]

It's looking like subclassing Collider is not probably not possible. That's a shame. Is there a strategy I can use to make a MonoBehavior act like a Collider?

[storm drum]

Here's a different way I could do this... Is it possible to create collision shapes that cause collisions with rigid bodies only when portions of the rigid body are outside of the shape?

For example, a ball shape dropped on top of a cube shape, or thrown against the sides, bounces off the side it hit. But can I invert the cube shape, so that the ball can only ever be with the cube, and bounces around inside the cube?

Likewise, an inverted sphere body with a cube inside... Can that be done without resorting to mesh shapes?

[warm pilot]

I have a character made from 5 articulatedBody. I'm trying to train it with mlagents. when I reset the training scene there's a pause (probably resetting the physics objects?) and it appears to screw badly with the first physics frame after that. is there some obvious way to avoid this timing problem?

[carmine basin]

If I was to "grab" something using joints, would it be better to create the joint when it grabs, rather than having an existing joint and just changing the settings to lock it

[warm pilot]

great question! test it and see?

i imagine if I create the joint at time of grab then the positioning is perfect (grabbed thing will not "pop") and I can test "do you have a joint" to know if something is being grabbed.

[burnt tulip]

Hello! well I'm making a pinball game and it goes something like this, but I want to make that when the "flippers" move by means of physics only one position of the flippers is stuck? i.e. I want to move only the tip and that the rest is stuck to the mini wall.

[warm pilot]

so a pivot?

i'd make an invisible root body that is not affected by gravity and is immovable. then I'd attach both flippers with rotation constraint and angle limits (I'm familiar with doing this in an ArticulatedBody). Finally I'd make some sliders in editor to test the range of motion and the look/feel is right.

getting the mass of the flipper vs mass of ball right will be fun to tune.

[weak turtle]

Hey, I am trying to make a drone that hovers in the air, so I tried turning gravity off for that drone, but as soon as its colliding with something its out of control and getting pushed back infinitely, is there a way to fix that?

[oblique cipher]

Does it work fine with gravity on? Using add force if under it's target position to stay up?

@weak turtle

[bleak umbra]

Yes by applying drag https://docs.unity3d.com/ScriptReference/Rigidbody-drag.html

But aside from that you need to apply stabilizing forces

[slim ice]

I'm using unity physics with DOTS, and I'm making a space game because we don't have a enough of those. lol. I have a cube on a spinning planet but it keeps falling off the planet instead of staying on the planet.

falls off

I'm guessing it's because everything just falls down using the Y axis, which wouldn't make sense in my case

[timid dove]

This is called gravity ma'am

[timid dove]

Yes, you'll need to implement your own custom gravity system for a game like this

[slim ice]

so, how?

I feel like that creates more questions than answers

[timid dove]

It's not incredibly complicated, if you understand how forces work

And how gravity works

Basically you just apply a force towards the center of the planet

[slim ice]

well, I understand that there should be a force that pulls it towards the large mass and to stay on it, there should be a force holding it up

[timid dove]

Yes to the first part

The second part, no

You should disable the normal gravity

[gentle olive]

Hello, I'm having a weird issue with what I think is a physics issue. Firstly, its a 2d game and for rotating the sprite left and right I change the scale of the parent game object. However if I jump (using Physics.AddForce(...)) I jump into a wall, than change the direction as I hit the wall my character clips into the 2d collider I have setup on the tilemap. In the example, if I try move right to get out of the wall, I'm stuck, but if I run left it shoots me back out to the right side of the collider (where I initially clipped).

I'm having trouble figuring out what exactly is happening here. Does anyone have any suggestions?

[timid dove]

Likely your collider is not totally centered or something, such that changing the scale ends up putting your collider inside the wall or something like that

[gentle olive]

Thats what i thought and i checked and the sprites always centered with the colider

[slim ice]

Can I make a thread for my issue?

[gentle olive]

all my movement and physics is done in fixedupdate aswell

[timid dove]

Is it done using a physics friendly method?

[gentle olive]

here ill post the code since its not toooooo long and ill take out anything thats not needed for this question

protected virtual void FixedUpdate()
    {
        Vector2 worldMovement = new Vector2(inputVector.x * moveSpeed * Time.fixedDeltaTime, rigidBody.velocity.y);
        rigidBody.velocity = worldMovement;

        if (inputVector.x > 0 && !bFacingRight)
            Flip();
        else if (inputVector.x < 0 && bFacingRight)
            Flip();
    }

    // move to movement component
    private void Flip()
    {
        bFacingRight = !bFacingRight;
        Vector3 scale = transform.localScale;
        scale.x *= -1;
        transform.localScale = scale;
    }

    public bool DoJump()
    {
        if(CanJump())
        {
            isJumping = true;
            rigidBody.AddForce(new Vector2(0, jumpForce), ForceMode2D.Impulse);
            OnJumpEvent.Invoke();
            return true;
        }

        return false;
    }

DoJump is called from another component

not to sure what you mean by "physics friendly method"

my tilemapcollider2d uses a composite collider 2d aswell.

[timid dove]

as opposed to like.. directly modifying the transform or something

[gentle olive]

yeah using addforce. had a brain fart in initial question. i add the force on the rigidbody

[slim ice]

I looked online and found this example, hopefully this works

[gentle olive]

@timid dove okay so i made the collider on the player wider and its not happening anymore...so i think your suggestion worked. Ill fiddle with it a bit more. Thank you so much!

[slim ice]

Here's the example in case others are interested https://github.com/Unity-Technologies/EntityComponentSystemSamples/tree/master/PhysicsSamples/Assets/Demos/6. Use Cases/PlanetGravity

[gentle olive]

I was just about to ask for that. Looks like theres some cool stuff in there

[slim ice]

Just making sure you are aware that the physics engine I'm using is experimental and buggy. I'm just testing what is possible for a prototype.

[drifting sleet]

just a basic marble game

[night latch]

@drifting sleet (trying to accurately move a marble with physics) I am modeling the marble as uh, a rigid body with interpolate and continuous, and then a sphere collider with a physic material "marble" with some bounce and slight friction

[drifting sleet]

your run of the mill, standard, classic, no fuss, no muss, no problem marble game

[night latch]

yee

haha

[drifting sleet]

you take a marble

you put it in, a thing

and you move the thing, and the marble is supposed to move in the thing

but it don't move good

the thing that is running into the marble

that makes it not move good

what is it?

[night latch]

for this the character is actively moving the marble, and I'm wanting any collisions to just accurately add the forces (maybe be bad terms here) to the marbles. The thing is a rectangle, rotating with a script

[drifting sleet]

okay

the thing is a rigidbody that's kinematic

that you are rotating with a translate?

[night latch]

its kinematic yes

[drifting sleet]

see that was your mistake

[night latch]

transform

[drifting sleet]

if you want this thing to interact with the marble rigidbody correctly

it can't be kinematic

you have to add an angular force

/ set the angular velocity

[night latch]

well I have tried both I can uncheck that though

[drifting sleet]

part two

rectangle - you mean like a paddle?

how is it attached?

[night latch]

it's just floating in space spinning

hm, I forgot I changed it. It was kinematic because it would fall if not, I forgot what I did

[drifting sleet]

that's because it's kinematic

yeah

well you're close

[night latch]

okay yeah I was just testing, also don't know the right way.

Do I have to build things physically sound to expect good physics, like I cant just make it float and stuff

wasnt trying to waste your time. Well, is there any good place to learn basics of physics?

thats what Im lookin fer ser

[drifting sleet]

yes

[drifting sleet]

not at all 🙂

i'm just messin

yes you should recreate things

in order for them to work well

based on what you described

it sounds like the ball gets hit by a rotating paddle

and it behaves weirdly

which is odd

pinball games work well in unity

[night latch]

while within the radius of the spinning paddle, it will be swept along with it just fine, at the right speed, centrifugal force gets it to the outside of the paddle, then once it's let go, it just doesnt carry it's speed.

but it's not glitchy or anything

well I guess it is? idk, it's the same every time, just wrong.

but I

'm down to recreate and learn right, just need some resources if anybody's got em.

maybe its unrealistic to expect, may be a lot. seemed simple enough lol

[drifting sleet]

you might just need to increase the static friction of the ball

also the paddle probably needs to be much heavier

[night latch]

yeah. hm can I send you a build or nah?

I tried that when it was kinematic

also, if it works, then my marble's speed was so fast that it was moving not 1:1 to it's skin. I had a better motion and lost the code in a tragic beginner mistake, so trying to start over as right as possible. I had it working veery well in this build with different physic materials.

it's okay if not. Mainly just looking for where to learn

[night latch]

got the motion back. it looks so dang good honestly. It looks like it's gonna sling it, then just all the momentum is a lie

I think it's more than the max speed of my marble's movement abilities and it just caps

yet, it moves that fast, while against the spinning unattached rectangle that is close to the ground

[static shore]

Why my gameobject jumping left side on next frame? Can anyone help me with this hinge joint thing . i'm adding "connected rigidbody" at runtime on trigger enter.

[elfin flax]

Hey which version of PhysX are we using in Unity??

[bleak umbra]

PhysX 4.1

[stuck bay]

hello, new here and to unity how do i stop my object from falling from the damn cube that i want to use as a floor

[timid dove]

you need your objects to have colliders

and you need to move your moving objects in a physics friendly way

[stuck bay]

ok i added box collider to my dummy model

when i play the dummy doesn't fall down

but there's a gap between the dummy and the cube

is it supposed to be this way?

[timid dove]

You have an animator

it's probably oerwriting the position of your dummy

but also - show the scene view

show the collider gizmos

etc.

[stuck bay]

i didnt follow

[timid dove]

try disabling the animator for a moment

[timid dove]

You didn't have to delete it

disabling would have been fine

anyway - show scene view

and show the collider gizmos

[timid dove]

turn on gizmos

so we can actually see the gizmo

[stuck bay]

i downloaded basic motion model from asset store and they have all this basicdummymodeljump/idle etc etc

but how do i actually use it and get my model to jump or run?

[timid dove]

see your collider is touching the floor

that's why you don't fall

[timid dove]

I recommend using these: https://blog.unity.com/games/say-hello-to-the-new-starter-asset-packages

[stuck bay]

my collider isnt with my model?

[timid dove]

you can see that it is not

[stuck bay]

how do i put them together ?

[timid dove]

move your model

[stuck bay]

where to?

[carmine abyss]

Hi
Can someone help? I'm trying to add gravity to my cube but it won't work. I have gravity turned on in the rigidbody component. I can add a screenshot if needed.

[timid dove]

show screenshots, yes

[carmine abyss]

Ok

Gravity is on but it still won't work

[timid dove]

what other components does the cube have

scroll up

[timid dove]

and scroll down too

what scripts are on it

and what do those scripts do

[carmine abyss]

And that is it

I wanted to solve the gravity thing before i worked on the collision script

Also, in my project settings the y gravity is set to 9.81

[timid dove]

are you actually running the game?
is time scale set to 0?

[carmine abyss]

Time scale is set to 1 and I wasnt running the game in the picture but when I do it doesn't work

should I set the time scale to 0

[timid dove]

No... only if you want time to be paused

[carmine abyss]

Ok

I don't really know what's causing the gravity to not work

[timid dove]

disable all your other objects

to test

except the camera of course

[carmine abyss]

It works now

but when I enable the ground, the block just falls through

[supple sparrow]

Does your ground have a collider ?

[wraith junco]

So I'm working on custom raycast wheels. I got the suspension and turning right and I'm sort of faking sideways friction by cancelling out any sideways forces relative to the wheels. Can someone explain in laymans terms basic correct ways to do sideways friction?

Do I basically just have a "sideways force limit" where if it breaks it, the car is allowed to slide sideways a little bit while still cancelling out the sideways forces, but in smaller amounts?

[timid dove]

friction is generally modeled as coefficients of static and dynamic friction. Once static friction is overcome, you switch to the lower dynamic friction coefficient

[stuck bay]

I've got a weird problem if anyone can help. I'm making a simple pinball game, but the ball (with its own rigidbody and sphere collider) will pass right through the flippers (who also have colliders and rigidbodies) if they are in motion. I've made a little animation to show the effect (pardon the low framerate). All relevant parties have continuous collision detection. The flippers are actually tied to a empty object which rotates to give the flippers the right angle of motion. I've done a ton of research on this but have mostly just found people with the same unsolved problem.

[timid dove]

Most likely you're not moving your flippers in a physics friendly way

if you're just directly rotating them via the Transform for example, that's not going to do it

[stuck bay]

That's precisely how I'm doing it, thanks for confirming that. I've come across hinge components in my troubleshooting, would that be the direction to head into?

[timid dove]

no

The most straightforward way to do this is to use the MoveRotation / MovePosition methods on the Rigidbody. The Rigidbody should be kinematic.

and this should only be done in FixedUpdate

rotating via the Transform is akin to simply "teleporting" from one position to the other

[stuck bay]

Thanks for the tips!

[storm drum]

I've discovered ModifiableContactPairs in Unity. I have an interesting use case I'd like to discuss with someone that is deeply familiar with them. Please let me know if you can help.

[obtuse seal]

Hi, I have a player that is using physics based movement that I wrote my self and has physic material with zero and minimum friction attached to it.
I also have models that I imported from blender, added box colliders to them and attached that same material to them too.
The problem is that for some reason my player is still getting stuck to the walls and all that.
Say that I am running and jump on to a wall, I won't fall down I'll just keep sliding along it or be stuck.
Could someone please help me figure this out?

[obtuse seal]

if you have an idea what might be causing it please @ me

[winter jetty]

@obtuse seal if you are using rigidbody.AddForce for movement that could be what is causing that to happen

[obtuse seal]

No, I am doing rigidbody.velocity += new V3...

[coral mango]

That is definitely gonna cause problems.

[timid dove]

why you say that?

and I ask because of my question in a certain other channel that you are also in...

[obtuse seal]

well how am I supposed to make a physics based movement then?

[coral mango]

You're generally meant to add force rather than setting the velocity in most cases.

[quartz wyvern]

so i have a RB that i toggle isKinematic on/off depending on a situation. but when i disable kinematic it continues on with the velocities it had before it was set to kinematic. so i fixed it with this:

_rigidbody.angularVelocity = _rigidbody.velocity = Vector3.zero; // cancel effects from forces etc
_rigidbody.isKinematic = true;

But according to unity you should not do this anymore it gives out a warning. So how do you clear previous data ?

[timid dove]

Something like this.

void FixedUpdate() {
  Vector3 path = _destination - rigidbody.position;
  Vector3 direction = path.normalized;
  Vector3 velocity = direction * _speed;

  // if our velocity would overshoot, we need to clamp the velocity a bit.
  if (velocity.magnitude * Time.fixedDeltaTime > path.magnitude) {
    velocity = path / Time.fixedDeltaTime;
  }

  rigidbody.velocity = velocity;
}```

[meager latch]

Hello

I started to work with wheel coliders.
Added four wheels to a thin rectangle and it span out of control upon landing on the terrain.
What could be the variabel that make it act this way?

Recreate my problem:

Game Object
Four child objects with a wheel collider
Set radius to 0.2
An rigid body to the first object

[timid dove]

it's creating a velocity that will travel the entirety of the path vector in a single fixed timestep

d = rt
so
r = d / t
d is distance, t is fixedDeltaTime

basically if you just kept the same speed velocity, you will overshoot in the last fixed update

this is to hit the target perfectly/not overshoot

[meager latch]

I solved the problem, it needs a box collider above the wheels 😄

[timid dove]

I think what you really want is a PID controller and to use forces

yeah they can be tricky but one you get it down it will give the most satisfying results I think

The best part about the PID controller is that it will allow your object to still be susceptible to outside forces, while still very convincingly doing what it's supposed to do

[ebon flax]

Hello, i don't know where i can ask my question, so i'm gonna write here. I want create a a racing car game, but i don't know what is the better controller for my car : wheelcollider and the system associated or add a vector3 on my car... somebody can help me ? thank you 🙂

[timid dove]

"add a vector3" < whatever this is it sounds way too primitive to result in anything realistic

[burnt tulip]

Hey guys I have a problem

How can I make so that only the flipper moves and the anchor stays still? should I use some joint? and if so please give me an explanation on how it is, I already separated the sprites the flipper and the anchor, I just want to know how I can connect them by means of physics so that only the flipper moves and the anchor stays still.

[rich ember]

hey all, does someone know answer to question ?

When i attach rotation script on object A (has mesh collider)
And when i drop object B on it with collider and rigid body , it falls onto it, but it does not rotate with a wheel itself then its standing and not moving at all
how can i apply rotation on object B to follow object A rotation without attaching same script on object B?

[stuck bay]

I've got a hinge joint that works fine as long as the motor is disabled. When I enable the motor it ceases all movement. Any ideas why this is happening?

[timid dove]

there's no real reason to "connect" them. Just make the flipper's pivot at its... pivot point, make it kinematic, and rotate it with MoveRotation in FixedUpdate

[burnt tulip]

wdym?

Can you explain me?

[timid dove]

that should happen automatically due to friction between the objects. The only way it wouldn't happen is if you:

• have a script overriding/controlling its rotation
• have rotation constrained
• are moving things in a non-physics-friendly way.

[timid dove]

that was the explanation. Which part are you confused about?

[rich ember]

Hm
Oke thanks for answer I'll check those conditions

[timid dove]

most likely you're not rotating object A in a physics-friendly way

you're probably rotating it via the Transform

[storm drum]

So a few days ago I was in here asking about programmatic non-primitive collider shapes without using mesh colliders. I discovered ModifiableContactPairs and have been using those to solve my problems: https://forum.unity.com/threads/experiments-with-modifiablecontactpairs-inner-shape-collisions.1308105/

[cunning crater]

Hi, im trying to match the rotation of my mesh collider with the rotation of the bone I attached it to. Its already matching transforms.

Any ideas?

I figured it out. I was linking it to the wrong bone >:|

[ebon flax]

When i use the wheels collider système my car is shaking when i speed up

[umbral drum]

hi guys, i'm trying to make a cube heavier on one or more corners, i've tried messing around with rigidbody.centerofmass but even tho the visual debug says my center of mass is correct, it does not work as i wanted to

here's my dice, the blue balls are the corners that's supposed to be heavier, to do this i'm iterating through all the corners, adding the normalized difference from the corner to the dice center to a temporary vector3, this part is working fine, i can get the center of mass where i wanted to

but my cube doesn't lands on the correct corner

instead i'm getting some weird gravity-related issues

the centerofmass of my cube looks like this (yellow dot), but he doesnt lands on the side i wanted

[sage yoke]

https://github.com/AoTTG-2/AoTTG-2/issues/453

Guys i'm working to a project with some other peoples, and we are tryning to create a remake of a game that was originally created on Unity 4, now we are using unity 2020, but since that we're having throuble related to the update of PhysX, and we are getting very bouncy collision, can someone help me to figurate out how to fix it?

[supple pawn]

Anyone has any idea why the object is not rotating? I made my own implementation of a damped spring system in Unity and that seems to be making that problem,

    {
        float force;
        float _damper;
        
        Vector2 direction = (upperPos-lowerPos).normalized;
        Vector2 velocity = Lower.velocity;

        force = springForce*(travel-Vector2.Distance(upperPos, lowerPos));

        if(useRelativeDamping)
        {
            damper = (springForce*travel)/relativeDamper*multiplierDamper;
        }

        if (Vector2.Distance(upperPos, lowerPos)<previousDistance)
        {
            _damper = damper*compression;
        }
        else if (Vector2.Distance(upperPos, lowerPos)>previousDistance)
        {
            _damper = damper*rebound;
        }
        else _damper = damper*compression;

        Lower.AddForce (force * -direction - (velocity-Upper.velocity) * _damper*Time.deltaTime);
        Upper.AddForce (force * direction + (velocity-Upper.velocity) * _damper*Time.deltaTime);
        previousDistance = Vector2.Distance(upperPos, lowerPos);

        //Debug.Log(force);
        //Debug.Log("currentTravel = "+ Vector2.Distance(upperPos, lowerPos));
        currentTravel = Vector2.Distance(upperPos, lowerPos);
    }

    void FixedUpdate()
    {
        Vector2 upperPos = Upper.position;
        Vector2 lowerPos = Lower.position;
        if(isShock)
        {
            upperPos = lowerPos + new Vector2(0,travel);
        }
        Spring(upperPos, lowerPos);
    }```

When I lower the spring stiffness, the error stops being as drastic, I'm  guessing the problem is on these lines 
```Lower.AddForce (force * -direction - (velocity-Upper.velocity) * _damper*Time.deltaTime);
        Upper.AddForce (force * direction + (velocity-Upper.velocity) * _damper*Time.deltaTime);```
Maybe the direction calculation is not right,
`Vector2 direction = (upperPos-lowerPos).normalized;`

[supple pawn]

Porfavor

[quasi kestrel]

cool stuff

[supple pawn]

Only if it worked

[quasi kestrel]

oh well.. shoot

[carmine basin]

So, might be a bit weird what I'm doing here. I want to make something animated interact physically with other things.
Two approaches I'm thinking of are this - use some kind of maths thing + non-physical hit detection then add forces to target bones/entities
or
Active ragdoll setup for just the player's upper torso. That way, the legs animate perfectly but the arms have the physics that I want

[stuck bay]

for ur first approach u cant add force to animated body

[carmine basin]

I don't mean adding a force to the animated body. I have an active ragdoll for my monsters

So they're physically simulated

[stuck bay]

if u have an active ragdoll, then u need nothing more than that

[carmine basin]

Could I just add a kinematic rigidbody and colliders onto my player's weapons for hit detection?

[stuck bay]

sure add rigidbody to weapon just as u did for bones

[supple pawn]

No one knows why that might be happening? Maybe I'm not taking mass into account or some weird physics stuff

[supple pawn]

The problem seems to be in the (velocity-Upper.velocity) calculation...

Upper.AddForce (force * direction + (velocity-Upper.velocity) * _damper*Time.deltaTime);```

[potent notch]

not quite certain if this is the place to ask, but im trying to create metaballs, and cant find any tutorials anywhere, does anyone have links to any good begginer tutorials/articles?

[sage yoke]

did someone here ever tried to write a custom physic engine?

[unique cave]

Someone for sure have did that. Just ask your question and someone will answer if they know

[sage yoke]

basically i would like to remake the PhysX engine that use unity 4, but never tried to do similar things

[timid dove]

PhysX is open source - so I don't see why you would need to rewrite it from scratch.

what you would have to do is create managed wrappers in C# around all the PhysX stuff via https://docs.unity3d.com/Manual/NativePlugins.html

[sage yoke]

i want to have the version of PhysX engine from unity4 to unity 2020

[timid dove]

i understand that

that's what all my advice is geared towards

[sage yoke]

since i've never done a similar thing before i'm a little bit lost

[timid dove]

it's not trivial. It's probably not worth the effort

[unique cave]

But why? Because there was dynamic mesh colliders? Btw it was also much less optimized

[sage yoke]

tbh i'm not really sure that this will fix the issue, but i'm remaking a game made with unity 4, and i upgraded the engine in the 2020 and the collisions now are strange, even tho it's the exact same as the old one

so i think that is because of the physx update

[unique cave]

Lol, and first thing that came into your mind was to remake the physics engine to make it work 😅. You know people make games with newer unity versions too?

[sage yoke]

not really

i tried to mess arround with everything

changing controllers, physic materials, even made a collision dumper script

but nothing give the same feeling as the original game

[unique cave]

Maybe try to ask that then instead of recreating everything, as I said, theres many cool games made with newer unity versions too. Youre trying to find a way to make your incredible solution work instead of fixing the original issue (xy)

[sage yoke]

the fact is that i don't find any issue with the game itself and with the collision itself, since those are identical to the old version of that game, and even tryning to change physics settings dosn't look to change anything

i don't want to remake the Physx system, it will be a pain xD, but i didn't find any other solution

[unique cave]

Solution to what? Maybe try to ask your actual issue with all relevant details and maybe some image/video comparisons. Most likely someone here would know the ”other solution”

[sage yoke]

i already sent them a little while back, i sent it again give me 5 seconds

https://github.com/AoTTG-2/AoTTG-2/issues/453 here it's a detailed post on the issue

[unique cave]

What collision detection mode are you using for the character?

[sage yoke]

Continuous Speculative (sorry for the late answer)

i tried also to change that, but seems always off

[unique cave]

That seems very buggy… maybe youre screwing something up in the character controller script? If you just let the character freefall at the same height and angle without any controller scripts attatched, does that still happen?

[tawdry lodge]

i just started can anyone tell me how to add physics to a 2d object?

[unique cave]

Watch any 2d physics tutorial

[tawdry lodge]

ok

[sage yoke]

i can check, but problaby nothing will happen since those bounce happens only with an high speed and we kinda fixxed the collision on the floor, are only the walls that seems odd

[unique cave]

I think simply continuous is the mode youd like to use in this case

[unique cave]

So what about the walls?

[sage yoke]

they are regoular static object with non convex mesh collider

walls and trees

both have issue on collision

[unique cave]

What issue

[sage yoke]

after the collision the character less very low speed

the trajectory seems to be the same exact one, but the speed is always a little bit more

[unique cave]

I think the new one is probably more accurate tho

[sage yoke]

mhh not really, or at least not for the old community of that project, basically if u keep all that speed u can bounce between multiple trees a lot of times before stopping

before this project there was another one to try to make a "remake" of that game, and also in that version there are collision issue, so i don't think that is because of code, but because of updated PhysX engine, even tho i'm not 100% sure

[unique cave]

Maybe the engine have changed but I doubt they made it less physically accurate

[sage yoke]

maybe it's "more accurated" in this way, but the main problem is that the community of that game is used to having the old collisions, and the game feels a lot better with the old ones

[unique cave]

Maybe you can decrease the speed yourself based on he impulse on every OnCollisionEnter (maybe filter ground collisions out of those calculation if you want only wall bounces)

[sage yoke]

yeah but i'm not quite sure on how to do that since we need to check both speed and angle of collision

[unique cave]

Dot product between the normal of the hit and velocity could be helpful

Or complement of that rather

-dot(normalOfHit, velocity) should give 1 when hitting the wall at perpendicular angle and 0 when hitting the wall at parallel angle (meaning you are going same direction as the wall and barely touch it). The value of the dot product also give anything between 0 and 1 depending on the angle and velocity. When you get smaller value, the change in velocity should be smaller I think. You should use the unmodified velocity (not the one thats already affected by the hit. I beleive the value of rb.velocity is already changed when OnCollisionEnter is called, im not sure tho) for the velocity so youd need to keep track of the velocity in every FixedUpdate to get the velocity before the impact.

[sage yoke]

ok, i will try that, thank you ^^

[unique cave]

Good luck. I have to go to bed now, I’ll be here tomorrow at some point

[floral fossil]

How do I prevent stuff clipping through other stuff when working with high speeds?

[timid dove]

1. make sure your objects are moving in a physics friendly way
2. Use continuous collision detection on the fast moving body
3. make thebodies larger
4. make them move more slowly
5. do custom raycasting/spherecasting etc in FixedUpdate

[floral fossil]

I'll try those, thanks!

[torpid marten]

Can someone explain to me what exactly "Convex" means on Mesh Colliders? I have a thin cube with a hole inside which i wanna use as a wall with a door, but Unity says this needs to be a Convex to work, however the with convex enabled, the hole gets ignored in the collision mesh

[frigid pier]

Don't make it dynamic physics object. Static objects are fine with non-convex mesh colliders

[torpid marten]

Well i need it to be a wall on a space ship so it has to move at some point

What exactly is the difference between convex and non convex?

[frigid pier]

Kinematic works as well

It's limitations of the PhysX AFAIK

Convex shape is easier to calculate collisions for

[bleak umbra]

also

[timid dove]

doing it "on a thread" may not be possible with Unity's physics engine for GameObjects

you can do multi-scene physics to do a bespoke physics simulation though

https://docs.unity3d.com/Manual/physics-multi-scene.html
https://learn.unity.com/tutorial/multi-scene-physics

[tribal sluice]

my game is getting laggy is this too many rigidbodies

[timid dove]

You should use the profiler to diagnose any framerate issues before jumping to any conclusions about a cause.

[tribal sluice]

WHAT IS THIS

why are my rigidbodies misbehaving???

slightly devious

rather mischievous

utterly unacceptable

[timid dove]

that tutorial famously doesn't work

because the truck is not moving in a physics friendly way

you'd need to move it via the Rigidbody, but the tutorial moves it via the Transform

[tribal sluice]

i tried making it move with rigidbody.AddRelativeForce but it kept going all sussy

wait that was while i was still multiplying by Time.deltaTime in the OnMove function

[timid dove]

simplest would be using MovePosition in FixedUpdate

or setting the velocity

[tribal sluice]

ok thanks :)

i'll try that

omg the turning on this truck is so smooth!

can you get a degree in writing bad code

because if you can i know what i'm doing at uni

wait isn't that just eventually malware

ok this actually works decently now thank you very much for the help! :)

[neon solstice]

Hello. I have added a simple character movement controller using physics

{
    // forward movement speed
    public float forwardSpeed = 25f;
    // side to side movement speed
    public float strafeSpeed = 7.5f;
    // how fast we move up and down
    public float hoverSpeed = 5.0f;
    public float rotationSpeed = 25.0f;

    private float activeForwardSpeed;
    private float activeStrafeSpeed;
    private float activeHoverSpeed;

    private float activeRotationSpeed;
    // Start is called before the first frame update
    void Start()
    {
        
    }

    // Update is called once per frame
    void Update()
    {
        activeForwardSpeed = Input.GetAxisRaw("Vertical") * forwardSpeed;
        activeStrafeSpeed = Input.GetAxisRaw("Horizontal") * strafeSpeed;
        activeHoverSpeed = Input.GetAxisRaw("Hover") * hoverSpeed;
        activeRotationSpeed = Input.GetAxisRaw("HorizontalTurn") * rotationSpeed;

        Vector3 forward = transform.forward * activeForwardSpeed * Time.fixedDeltaTime;
        Vector3 strafe = transform.right * activeStrafeSpeed * Time.fixedDeltaTime;
        Vector3 hover = transform.up * activeHoverSpeed * Time.fixedDeltaTime;
        Vector3 torque = transform.up * activeRotationSpeed * Time.fixedDeltaTime;

        Vector3 movement = forward + strafe + hover;
        // this.GetComponent<Rigidbody>().MovePosition(this.transform.position + movement);
        this.GetComponent<Rigidbody>().AddForce(movement);
        // https://docs.unity3d.com/ScriptReference/Rigidbody.AddTorque.html
        this.GetComponent<Rigidbody>().AddTorque(torque);
    }
}

It was working fine