⚛️┃physics

[lavish rose]

I think if a collider is applied, making it a trigger is just one click away... Plus, it can selectively trigger only on one concrete object entering...

[eager oar]

I am using a collider, but turning trigger on isn't working and I am not even using a onTrigger function in my code

[lavish rose]

but im not sure wheter the deletion would be fast enough to prevent the force to be transfered...

[lavish rose]

well, maybe you could 🙂

[eager oar]

and how do I do that , I am really a begginer you see...😅

[lavish rose]

bro, me too 😄

heheh...

w8 one..

so..

First you make a collider into a trigger...

[eager oar]

wich one

the bullet

or the traget

*which

[lavish rose]

i think the target....

[eager oar]

ok

[lavish rose]

but it should work on both...

[lavish rose]

then you make a piece of code somewhere (Preferably standalone script attached to the bullet or the target...)

and use this thingy...:

    private void OnTriggerEnter(Collider other)
    {
        Destroy(gameObject);
        Destroy(other.gameObject);
    }```

this method fires when the trigger is triggered (impact) and destroys the (gameObject) its attached to and the one it hit...

oooooor, if you want to attach the script somewhere else, go somehow like:

  private void OnTriggerEnter(Collider other)
    {
        Destroy(bullet);
    }```

This should destroy the bullet on impact.

but again... Im not sure it will be fast enough that the force wouldnt be transfered...

[eager oar]

if it is a trigger, it doesn't collide

it just goes through I think

I will try it when I will be alble to

thanks in advance

[lavish rose]

hope it helps ;P

[eager oar]

just what is the "other"

[lavish rose]

its the other object its coliding with... (e.g.: if assigned to the bullet, the other is the target)

[eager oar]

oh ok

and how can I change this line

if (collision.collider.CompareTag("Enemy") && explodeOnTouch) Explode();

[lavish rose]

you want the Explode(); to happen if (collision.collider.CompareTag("Enemy") && explodeOnTouch) is treu?

[eager oar]

in short

if target hit = enemy, explode

[lavish rose]

 if (collision.collider.CompareTag("Enemy") && explodeOnTouch) 
{ 
Explode();
};

[eager oar]

my line works

but with on colision

[lavish rose]

oof, gonna take someone more experienced... 😄

[eager oar]

ok

btw you don't need {} for 1 line

you can just continue after the condition and finish the line with";"

[supple sparrow]

@eager oar What @lavish rose describes should work

Make sure you switch from OnCollisionEnter callback to the OnTriggerEnter one, because now you're using a trigger

[eager oar]

the command then tells me that collider is not valid

collision (which is the "other") works, but the rest of the command wont

@supple sparrow

[supple sparrow]

Also check params

Collision takes a Collision, trigger takes a Collider

[eager oar]

hm...

maybe tha is the problem

I will try it out give me a sec

[supple sparrow]

you can still access gameobject and such from it

check scripting API reference for whats available

[eager oar]

@supple sparrow

[supple sparrow]

do a compareTag directly on the collider object

you named your collider like when it was a collision

this got you confused

if (collision1.CompareTag("Player") && explodeOnTouch)

[eager oar]

is this ok ? if (collision1.GetComponent<Collider>().CompareTag("Player") && explodeOnTouch) Explode();

[supple sparrow]

overkill

look at the first param of your callback

its already a Collider type

and also its wrong because you would firt need to acces the .gameObject on the collision before doing GetCompenent

but that's another story, lots happening here 🙂

I would rename collision1 to collider to avoid further confusion when you get your code working

[eager oar]

ok

[supple sparrow]

aaaand not sure if compareTag works on a Collider. If it doesn't, acces gameObject first

sorry don't have Unity opened atm

[eager oar]

ok

by access you meant what exactly

[supple sparrow]

the scripting API has your answer
https://docs.unity3d.com/ScriptReference/Component.CompareTag.html

[eager oar]

still doesn't work

I will send the script instead.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class BulletEnemyScript : MonoBehaviour
{
    public Rigidbody rb;
    public GameObject explosion;
    public LayerMask WhatIsEnemy;

    //stats
    [Range(0f, 1f)]
    public float bounciness;
    public bool useGravity;

    //damage
    public int explosionDamage;
    public float explosionRange;
    public float explosionForce;

    //lifetime
    public int maxCollision;
    public float maxLifetime;
    public bool explodeOnTouch = true;

    int collisions;
    PhysicMaterial phys_mat;



    private void Start()
    {
        Setup();

    }

    private void Update()
    {
        //when to explode
        if (collisions > maxCollision) Explode();

        //maxLifetime explosion
        maxLifetime -= Time.deltaTime;
        if (maxLifetime <= 0) Explode();

    }

    private void OnTriggerEnter(Collider collider)
    {
        //Count down collisions
        collisions++;

        //explode if bullet hit an enemy
        if (collider.gameObject.CompareTag("Player") && explodeOnTouch) Explode();


    }```

 private void Explode()
    {
        //Instantiate explosion
        if (explosion != null) Instantiate(explosion, transform.position, Quaternion.identity);

        //check for enemies
        Collider[] enemies = Physics.OverlapSphere(transform.position, explosionRange, WhatIsEnemy);

        for (int i = 0; i < enemies.Length; i++)
        {
            //get Component of enemy and call TakeDamage

            //just an example!!!
            enemies[i].GetComponent<PlayerHelth>().TakeDamage(explosionDamage);

            if (enemies[i].GetComponent<Rigidbody>())
            {
                enemies[i].GetComponent<Rigidbody>().AddExplosionForce(explosionForce, transform.position, explosionRange);
            }
        }
        Delay();
    }

    //little delay (fixes bugs)

    private void Delay()
    {
        Destroy(gameObject);
    }



    private void Setup()
    {
        // create anew physic material
        phys_mat = new PhysicMaterial();
        phys_mat.bounciness = bounciness;
        phys_mat.frictionCombine = PhysicMaterialCombine.Minimum;
        phys_mat.bounceCombine = PhysicMaterialCombine.Maximum;
        //Assign material to collider
        GetComponent<SphereCollider>().material = phys_mat;

        //set gravity
        rb.useGravity = useGravity;
    }

    private void OnDrawGizmosSelected()
    {
        Gizmos.color = Color.red;
        Gizmos.DrawWireSphere(transform.position, explosionRange);
    }
}

[supple sparrow]

Please use hatebin.com next time 🙂

[eager oar]

oh

ok

thx

[supple sparrow]

your bullet is the one having the trigger ?

and have a rigidbody ?

[eager oar]

zes

yes

[supple sparrow]

the player is not a trigger ?

[eager oar]

or was it supposed to be that way

I did the opposite

[supple sparrow]

well the Trigger callback is on the bullet script

[eager oar]

well now I made it that way

[supple sparrow]

you can approach it both ways

[eager oar]

but the bullets just fly through

[supple sparrow]

but your code looks good like that a t a glance

Your player has the tag Player, right ? (sorry to state the obvious, but I work with what I can see)

[eager oar]

yes

[supple sparrow]

put a debug log in the trigger callback to check trigger really happens ?

[eager oar]

hm...

the log retur something

[supple sparrow]

before or after the if ?

[eager oar]

after

[supple sparrow]

alright then trigger is good, bug is elsewhere in the code

[eager oar]

I am looking for it rn

[supple sparrow]

👌

[eager oar]

something is wrong with the explosion function

[fiery bolt]

What does ignore raycast/UI do?

When it's ticked, does it mean UI will ignore raycasts?

[timid dove]

It's a layer

when an object is on that layer

raycasts will not hit it by default

otherwise it's a layer like any other layer, and there's not anything special about it other than the default LayerMask ignoring it

[safe lava]

hey, anybody know what vertex data values the BakeMesh needs, can't find any documentation or decompilation of it? Does it support custom vertex data structure at all or does it have to contain all the default mesh values?

[cedar hull]

how can i make this pushable and with gravity

[wise copper]

@cedar hull if both objects have a box collider and rigidbody it should already work

[cedar hull]

so i need a colider on the player model or does that already have one??

[visual thistle]

u need one

[cedar hull]

ok

[cedar hull]

the charater controler has a box very simular is it tat or do i need a collider on the player model

[uneven shore]

what people usually use for movement for a 2d platform game? raycasting? sphere/box casting? translate? rigidbody? etc

[wise copper]

@uneven shore personal preference honestly. You can get away with using a Rigidbody2D and changing the velocity, however you might notice that your character will stick to walls if you jump into them. I've made my own movement packages in the past that use raycasts to determine collision.
There's a really good series by Sebastian Lague on 2D collision detection using raycasts if you want to go down that route: https://www.youtube.com/watch?v=OBtaLCmJexk

[uneven shore]

@wise copper I actually just saw that yesterday, but it's a bit old so I was wondering if it's still relevant

[wise copper]

Yeah it's still relevant

[uneven shore]

Cool. What if my shape isn't square btw?

The raycast positioning seems to match a square (or square like) shape

[wise copper]

What shape are you thinking?

[uneven shore]

circle

[wise copper]

If you're planning on using physics for ramps and things like that, the Rigidbody2D might be the route you want to take

[uneven shore]

tbh I tried to use the rigidbody2d before, and it didn't look good. That is why I started looking and encountered the 2d platformer

[uneven shore]

I'm thinking on using collider cast rather than raycast. Any downside to that?

@wise copper

[wise copper]

nah not really

[earnest totem]

Hey, so i'm trying to make unity handle earth sized objects and distances and i already implemented that for distance, but i need to do it for speed. Someone told me its done by zeroing the speed of an object once it passes the glitch-threshhold and then "Passing that to the frame of reference", however i have no idea how that will fix it since that will just make the other objects go with the glitch speed, which wont make it any better. Any ideas? Thanks

[earnest totem]

Okay, well i got it to kinda work

However when i exert the velocity vector onto my planet which my cube is supposed to orbit around

the vector is only applied once... which means it just goes to the left

[loud ferry]

How do I make the character controller sprint when grounded, but also keep it's momentum while midair? https://hatebin.com/rjhlbsdvqk

[modest fable]

Maybe this is the more appropriate channel

i'm making a game where you control a character using ragdoll physics

for example by mapping a joystick to say, right leg up-down, left-right

How should i go about doing this? One idea i had was using torque

so torque is added in the direction where the stick is being held

or i could use rotation, but maybe that would compromise the physics system

[proper coral]

Is there a way to lock down two axis of rotation in a hinge joint so that it only rotates on one axis with absolutely no rotation in the others?

[viral ginkgo]

@proper coral doesn't hinge joint already allow one axis of rotation?

[proper coral]

no it's not very good at stopping that kind of motion

the joint still kind of wobbles in all three axis

[viral ginkgo]

if you make the body heavier, it should be more stable

if you are trying to make swinging ropes or something, you gonna have a hard time

[proper coral]

I'm having a wheel attached to a bolt pivot around a certain part of a frame

and the bolt wobbles in the frame on more than one axis

[viral ginkgo]

you sure joint anchor and connected anchors are good?

[proper coral]

no

should they be in the same place?

[viral ginkgo]

you'd wanna make sure wheel is attached by its center

[proper coral]

the wheel and the bolt are all one rigid body

I will send a picture

so the wheel and bolt and the part of the steering that isn't jointed at the bottom all act as one rigid body

the bolt should rotate on the z axis around the frame but it wobbles a lot

[viral ginkgo]

@proper coral i see

can you try making the bolt heavier

[proper coral]

I can

[viral ginkgo]

compared to the wheel especially

[proper coral]

but the origin of the entire system is the point of rotation

as you can see I want it to rotate around the origin

the bolt and the wheel are in the same rigid body

[viral ginkgo]

oh wait wait

hold on

[proper coral]

the wheel and the bolt rotate together yea

[viral ginkgo]

that sounds illegal

[proper coral]

it shouldnt be

[viral ginkgo]

i think you need bolt as a seperate rigidbody

[proper coral]

the design of the model is based of the ackerman steering concept

and I have separate wheel colliders that function

[viral ginkgo]

ah, wheels are wheel colliders of course

so they are like seperate bodies, i see

[proper coral]

I can stream it to you if you want so you can see how it functions?

[viral ginkgo]

yeah okay

[stuck bay]

heyyy

sup guys

need some help with a plunger animation for pinball game

i cant figure how to make so when you start the game if you press the down arrow key the plunger will go down and up and as soon as you press again it will launch ball

sry im very bad at explaining stuff

here is an example you can see at the 20 second mark

https://www.youtube.com/watch?v=SJ6lo1dUT6Q

[viral ginkgo]

you'd need to do that without using transform.position

[stuck bay]

why

[viral ginkgo]

you tried it?

[stuck bay]

no i did with translation

sry im very new to unity haha

[viral ginkgo]

if you had a spring attached to it,
and you wanted to wind it backwards
maybe then you could slowly pull it back with transform.position

also setting velocity 0 every frame

and then you'd stop doing that
and it would shoot

or toggle it kinematic instead of setting velocity 0 everytime

@stuck bay you basicly want physics and forces to do the shooting

[stuck bay]

so for the sprint joint id need to have a rigidbody on the plunger

[viral ginkgo]

or, you dont have rigidbody on the cylinder at all

and shoot the ball with "rb.velocity =" yourself

if you wanna handle the visual stuff in code

[viral ginkgo]

if you wanna do the spring style, yes

but you probably wanna have ball velocity more reliable

it might be different even if player winds the cylinder the same amount
if you use physics

[stuck bay]

connected body is gonna be ball right?

[viral ginkgo]

@stuck bay I was imagining cylinder would be attached to table via spring joint

cylinder would have colliders and rigidbody

and it would hit the ball to move it

[stuck bay]

what does damper do

Amount that the spring is reduced when active.

mmh

[viral ginkgo]

@stuck bay it slows down the spring

[stuck bay]

Ah

do i need to add a script or it could be all done with the components?

[uneven shore]

hey guys, I'm currently using the formula jumpVelocity = initialVelocity + acceleration * time with initialVelocity=0, accleration=gravity and time=timeToApex, and it works by then adding the jumpVelocity once.
I now want to modify my jump so that the player can hold the button and the jump will only reach the apex if button is held at maximum time.
What formula can I use for that?

[round hinge]

Hey fellas , quick question.

I'm making a bunch of bullets to go from one point and on and on till they reach some distance and disappear.

Would it be better if I used

sphere collider + Rigidbody + is Not kinematic

or

non Rigidbody + sphere collider

??

I'm asking cause I heard somewhere and somewhen that a collider should not move so much, and it's actually takes more cpu usages than using a Rigidbody...

And of course I don't remember who said it...

[stuck bay]

I would like to know if I turn physic off with "Physics.autoSimulation = false;" can I still use raycasting

[timid dove]

If you are planning on moving a collider it's best to give it a rigidbody

Otherwise the physics engine treats it as a static Collider and yes it's expensive to have to recompute the static Collider when it moves

[round hinge]

@timid dove thanks. So even though it's not marked as static, it's still treated as one ?

[timid dove]

The word "static" has a lot of different meanings to a lot of different systems in Unity

[round hinge]

@timid dove so, basically when we turn the static button on on a collider without any Rigidbody, it only affects the non-physical elements of the object ? ( Lightning etc)

And where can I find the detailed docs for that ?

[narrow tangle]

Apparently I have seen people giving configurable joints, target rotations, which should work, but for some reason my joint doesn't rotate towards target rotation please help

I need sort of animated ragdolls please help

[modest fable]

does that work with physics?

what force are you exerting if you make a target rotation i mean

[narrow tangle]

Maybe idk

[charred canyon]

hey guys

i am a noob and i have a noon question

i have 2 cubes objects with rigid body with some distance betwen

on one of them i put transform.Translate(Vector3.forward * Time.deltaTime * 20) and my objects intersect each other is this good?

i need another code for them not intersect right?

[glacial jolt]

@charred canyon moving rigidbodies directly with transform.Translate "teleports" them to the target location, bypassing any collision checks/resolution. You can either use AddForce or set the velocity manually on a rigidbody to get collisions working

[round hinge]

@timid dove I think you missed my question. I'd be glad if you responded :D

[round hinge]

This question

[timid dove]

Static colliders are documented here: https://docs.unity3d.com/Manual/CollidersOverview.html

It's completely orthogonal to the concept of static GameObjects:
https://docs.unity3d.com/Manual/StaticObjects.html This is mostly related to lighting, rendering, and navmeshes

[round hinge]

@timid dove Thanks a lot :D

[hidden wadi]

um is this supposed to happen when u add a Character Controller?

[timid dove]

Having both Rigidbody and CharacterController is unusual and they will most likely interfere with each other

[hidden wadi]

THX

[dreamy pollen]

Are there problems associated with moving a transform in fixed update that has a rigidbody attached to it? That's kosher, right?

I know about rb.MovePosition() and rb.AddForce(___, ForceMode.VelocityChange) but I have a very niche corner case where it seems adjusting the transform position might be my only solution

[timid dove]

moving the transform position directly is going to cause problems yes

Namely that collision detection is going to completely not work

It's also going to look unnatural if the RB has velocity, because the object will move one way from you moving the transform, and then it will continue to move with its same velocity from before next physics update

[dreamy pollen]

crud, you're right... drat

[timid dove]

what are you trying to do

[dreamy pollen]

#⚛️┃physics message

Pretty much still bashing my head against this

[timid dove]

Oh that again haha

[dreamy pollen]

yeah dude this sucks... if only I could simulate aspects of the world before others

Unity/PhysX doesn't work that way tho

[timid dove]

I still suggest trying to apply a force counter to the centrifugal force 🙂

[dreamy pollen]

I don't know what that would look like, unfortunately... I'm not the most wrinkly-brained 🧠

the one easy fix would be to reparent the player's transform to whatever he's standing on, but then the scale of all game objects must be 1,1,1 which sounds like a huge pain for development

also sounds like something that could easily introduce bugs, bleh

@timid dove I've never used RigidBody joints before... would a Fixed Joint be useful here?

[timid dove]

oh probably yes

not sure why I didn't think of that before

[timid dove]

Re: the scaling problem - you should really revisit your object hierarchy if you don't have 1,1,1 scaling all the way up and down the tree. You can have non-uniform scaling only on leaf nodes. Then you can avoid these problems completely

e.g. instead of having this: Disc (Scale 20, 1, 20) - with Rigidbody MeshRenderer, Collider Player (scale 1, 1, 1)

Do this:

  Disc Visuals (Scale 20, 1, 20) - with MeshRenderer, Collider
  Player (scale 1, 1, 1)```

[dreamy pollen]

Hrmm, the issue (if employing the method of reparenting) would be using the raycaster to determine the collider that contains the transform the player should reparent to. It would hit the Disc Visuals

[timid dove]

Then you do GetComponentInParent<Rigidbody>(), or transform.root

or use the RaycastHit.rigidbody

which will get you that parent automagically

[dreamy pollen]

Interesting, that's not so terribly nonviable after all

I still might look at what joints can do for me, I've never used them... I think I'd need to be assigning them every frame and disconnecting them, otherwise the player theoretically couldn't move using axis input

[timid dove]

Try em out

they're a little annoying to work with from script

because you can't just enable/disable them

they have to be created/destroyed as needed

and there's a lot of datapoints you need to set on them 😄

[dreamy pollen]

hrmm :[

probably less performant too

[timid dove]

For example @dreamy pollen here's some code I used for a project once where you have a grabby arm that can pick stuff up using a joint

https://hatebin.com/mcwfzfdlms

There might be a better way to preconfigure all of those parameters outside of code but I'm not aware of it

[dreamy pollen]

Good god...

well, it is what it is. I'll look this over and see if I can parse it

thank you again, @timid dove !

[timid dove]

np

[stuck bay]

i have a basic player that can move and sphere but idk how to make it if the player touches the sphere the sphere moves

(3d)

[viral ginkgo]

@stuck bay if you want physics interaction, make sure both objects have collider and rigidbodies

if you meant some custom movement via code, you can do any sort of collision detection you want

You'll get a callback called when two objects overlap if you use trigger colliders for example

[obsidian whale]

Im having trouble getting smooth/non-jittery movement. I have a camera -> empty kinematic GO with a config joint component (xyz pos locked, xyz rot unlocked) -> empty GO -> (whatever item, has a rigidbody). Im basically using it to make the item the player is holding slowly rotate towards the same direction as the camera, but the rotation is all jittery

I tried: transform.Rotate player and camera in fixed update // using rb.MoveRotation to rotate player & camera (inside fixed update) // transform.Rotate player + camera in late update //

[supple sparrow]

Did you try GO update in Update, Cam update in LateUpdate ?

[west trout]

Hey friends. Anyone familiar with the character controller, as an alternative to 'rigidbody+capsule collider'?
I deleted rigidbody and collider, in favor of character controller, but now i don't collide with floors anymore.
In every tutorial I've seen, they are automatically stopped by other colliders, but not for me...

[west trout]

ahhh, i figured it out.
character controller collides with rigidbody, but not with rigidbody 2D.

[proud nova]

3D and 2D physics are ran by different physics engines

[obsidian whale]

@supple sparrow yes,i tried cam update in LateUpdate, but the joint is just a component, I havent written a script for it. im just assuming its in fixedupdate since its a physics component

[shrewd peak]

Anyone know how to make a rope with similar physics properties to a power cable?

right now i just have a bunch of spheres that cant self collide with each of them having a configurable joint referencing the previous one

if i have each these settings it works but it doesnt "feel" like a cable

anyone have ideas for better settings or a better solution

[stuck bay]

ive tried but my player falls over and even if it does touch the sphere it has a tiny gap and doesnt move at all

[viral ginkgo]

@stuck bay make sure they both have rigidbodies

dynamic rigidbodies

not kinematic

[stuck bay]

they are

is my player falling over because im using character controller

?

[viral ginkgo]

i dunno rigidbodies fall over

you shouldnt have rigidbody and character controller at the same time

[stuck bay]

ol

oh

im gonna try another project where i use rigid body

[viral ginkgo]

@shrewd peak It's pretty difficult, it will be springy and it will perhaps not be able to carry its own weight if you have that many nodes

I don't think you can archieve a tight cable that doesnt get springy
using unity joints
with this many nodes
with standard physics update rate

.
gotta do some custom stuff for good rope physics

[stuck bay]

everytime i touch the sphere it will just keep sliding across the ground

[viral ginkgo]

well i dont know what you exactly want

[stuck bay]

nvm

[ornate phoenix]

I'm having some trouble with the "Calculating Lead For Projectiles" formula from the unity3d wiki. Is this the right section to ask? I'm technically using the velocity of a character controller

[dreamy pollen]

Does anyone have any experience with Physics Scenes? Does the API allow you to dynamically 'import' animated mesh colliders with rigidbodies from the main physics scene?

Based on the docs, it doesn't mention working with rigidbodies: https://docs.unity3d.com/ScriptReference/PhysicsScene.html

[timid dove]

Physics scenes in Unity are tied to Unity scenes

I'm pretty sure that you move Rigidbodies between physics scenes by moving them between actual scenes

I.e. https://docs.unity3d.com/ScriptReference/GameObject-scene.html

[wraith junco]

I need someone's help as soon as possible. I have a client and server simulation. Both have the SAME exact car prefab, but when executing the same movement from the same exact inputs, they end up in slightly different positions

I then booted up two new simulations, with just a flat plane and two of these cars, and they work fine and end up in exactly the same position, so I know it's possible

I just don't know what could be causing this

Cars are rigidbodies with wheel colliders btw

They're all running the same timestep too

I've looked over the car prefab about 20 times over. They're all identical. Code is all the same.

They all have the same interia tensor, intertia tensor rotation, etc, and yes, they both start in exactly the same position and rotation. Ground is exactly the same position too.

On the two new simulations I created, they end up in exactly the same position. Above is the server (left) and one of the new simulations (right).

Oddly enough, both the server and the client have different positions than both of the new simulations I created

This is so frustrating

All physics settings in the unity menu are exactly the same.

[wraith junco]

My physics character moves perfectly fine and stays in sync between the server and client by the way. So I'm guessing it's something fucked up with the wheel collider

The wheel colliders all have the same settings and are in exactly the same place on each prefab.

[wraith junco]

These are the values at which my car spawns in at, before the game starts. Even before applying motor torque or steering to the car, the values of the cars are different after the rigidbody settles (on my server project vs the new test scene project I made)

It's almost like my main projects have a buggy version of physx or some shit

These are the values ^ after the rigidbody cars are spawned in and let settled. No torque or steering or force applied to the rigidbody in any way. Server vs new test scene

And that ^ is both test 1 and test 2 project (the ones I just now created like 2 hours ago). Same as before, no torque or steering or force applied to the rigidbody, just spawned in and let settled

both exactly the same

I swear physx is fucked on my main projects

[dreamy pollen]

@wraith junco Looks like you are talking about determinism. This might boil down to an issue of floats producing different results between different architectures. Floats are notoriously imprecise... just checking if you were aware of that possibility

[steel verge]

Can change the layer disable a collider? My tilemap collider currently has the Default layer, so I changed it but now my collision don't work.

[wraith junco]

@dreamy pollen Physx is supposed to be deterministic on the same CPU vendor. This is on the exact same hardware but it's producing different results

however when I create two entirely new projects, I get deterministic results

[dreamy pollen]

@wraith junco ahh, sorry no idea then man. If you're on DOTS I think you could switch to Havok physics (I'm disenchanted with PhysX), but not many people are opting for DOTS at this time.

[wraith junco]

I heard DOTS is difficult and I'm not sure if havok has built in stuff to make cars

[distant coyote]

@wraith junco

I'm assuming you checked the important checkbox?

[wraith junco]

No, but that wasn't my point

I started up two brand new projects, and my cars are deterministic between those projects

same exact positions on every input I give it

[distant coyote]

ah

sorry didn't read thuroughly enough heh

[wraith junco]

but they're not deterministic between my server and client for some reason

its the weirdest thing

[distant coyote]

server sitting on linux>?

[wraith junco]

Nope

all on same hardware

[distant coyote]

headless?

[wraith junco]

nope

editor

[distant coyote]

client* is non-editor?

[wraith junco]

everything is run in the editor so far

I dont think a build is going to change determinism

[distant coyote]

so you have 2 instances of editor and you get screwy results?

[wraith junco]

Yes

I made a post on the forums and some other guy said he had the same issues with wheel colliders

[distant coyote]

(obnoxiously, the SceneView causes additional Update to occur, which with AutoSyncTransform turned on can do weird shit - independent of FixedUpdate)

[wraith junco]

doesn't happen with my rigidbody player by the way

just the wheel collider cars

[distant coyote]

hmmmmm this one might be worth me poking heh - sounds fun

anything else I should know about ur proj? VR? step size? etc?

[wraith junco]

Physics step is completely the same, made sure of it

non VR

all physics settings are the same

all wheel colliders are the same sizes, same exact settings

the interia tensor, interia tensor rotation, is the same across all of the same car prefabs loaded in

Even before adding force to the wheels, or adding steering, just dropping in the car makes them go to the wrong positions

on the server and client

like before the game starts, I have them at the exact same position. Game starts, rigidbodies settle, and they end up in different positions

the two new test projects I talked about do not experience this. Even when steering and adding torque to the wheels, they end up in the same position exactly.

[distant coyote]

you should probably check the Enhanced Determinism button

[wraith junco]

Doesnt that shit on performance?

[distant coyote]

Simulation in the scene is consistent regardless the actors present, provided that the game inserts the actors in a deterministic order. This mode sacrifices some performance to ensure this additional determinism.

try it first

[wraith junco]

provided that the game inserts the actors in a deterministic order.

What does this mean

Yeah that didnt work

I just did another test. Spawned in a rigidbody cube at an angle in the sky and let it fall

server ended up different than both of my new simulations

the two new simulations ended up identical

this is so fucked

[timid dove]

Whoever told you that networked physics simulations would be easy was lying

[distant coyote]

the best game of Spot the Difference ever 😛

@wraith junco are your Server and Client 2 different unity projects?

what are your step/maxstep too?

[timid dove]

maximum allowed timestep is important here! If the first frame (or any frame) of the game takes too long you'll hit that limit and everything will go out of sync

Good explanation on what that setting does: https://forum.unity.com/threads/what-is-maximum-allowed-timestep.330116/#post-2139556

[wraith junco]

Both identical

It's almost like if you make a project too far apart from one another, it gets a different physx generation value

if that's even a thing

Because I made the new projects back to back, and they both have exactly the same physx properties @distant coyote

[median wadi]

making a simple conveyor belt, any reason AddForce() wouldn't work on the object sitting on the belt, for an instant i got it to work if i turned off gravity on it after starting the game

[wraith junco]

The standard unity character controller still suffers from non determinism right?

I think someone said that, just wanting to make sure

[timid dove]

AddForce will work assuming you're not explicitly setting/overriding the velocity elsewhere

when I say "work" I mean that a force will be added. Not that you will achieve your desired behavior

[wraith junco]

Okay scratch that, now that I take a closer look at it, my rigidbody controller is not fully deterministic, and is ending up in different spots each time, though, with very small deviations

not big enough to cause problems

the wheel colliders are doing the same thing, but it's causing a massive deviation over time

lockstep it is

That still doesn't explain the 1:1 determinism in the two new projects that I created back to back though

[median wadi]

GetComponent<Rigidbody>().AddForce(direction, ForceMode.Acceleration);

[stuck bay]

can somebody help me with this issue

[median wadi]

weird, if i crank the direction up really high, the cube rolls

[stuck bay]

my flippers are not producing force

https://pastebin.com/LG2CSV38

this is my script

[stuck bay]

anybody there?

[pale geode]

I have a question, does physics in unity support weight? As in if I made a seesaw and put more mass on one end will it tip over?

Also will the force applied to the seesaw increase with distance fron the center of rotation?

[timid dove]

Yes to all of this

[pale geode]

Awesome, based on reading online it was unclear to me

[timid dove]

Except the force doesn't increase, but torque does

[pale geode]

Yeah

[timid dove]

But i got what you meant

[pale geode]

So, would something like actual gears driving each other be feasable to make without too much additional scripting?

With different ratios interacting

[timid dove]

Soooo actual gears with teeth would be kinda rough

[pale geode]

Really?

Damn

[timid dove]

That's a very complex Collider, and depending on how fast they're spinning, you would need quite a small timestep to get accurate results

You could certainly try it out and let us know how it goes though

[pale geode]

Why not, im just glad to know unity atleast supports the physics of it

Also, is there a reason why its not possible to get the current force exerted on a rigidbody?

[timid dove]

Mostly the collisions with those complex Colliders will be the main issue I think

[pale geode]

It can be simplified

Made out of primitive colliders

[timid dove]

The Rigidbody simply doesn't store that information

When a force is applied, the body's velocity and angular velocity are changed

And then the force information itself is discarded as no longer necessary

[pale geode]

Oh, but how difficult is then to make an object that breaks under the weight of something? Since if the objects are just sitting on top of it, the velocity is 0

[distant coyote]

"Rigidbody" 😛 its not a "Flexible tensile strength body"

as far as calculating the total force of a single rigidbody ... use math. velocity * mass = linear force

if it hits something head on

[pale geode]

Yes but im talking about static force

If i just place a heavy object on top of another

And want it to break

[distant coyote]

ah so you want like... "How many pounds"

[pale geode]

How does it acces that info if the velocity is 0

[timid dove]

You can get impulse from a Collision contacts: https://docs.unity3d.com/ScriptReference/Collision-impulse.html

I wonder of they'd add up to the weight of a sitting object..

Never tried it

[distant coyote]

lol I'm aaaactually curious to know this one

[pale geode]

I wonder too

Also, i have one more question, is it better practice to spin stuff with addtorque or with the motor of a hinge joint if available

Is there a big difference or no?

[distant coyote]

hinge joint has other useful features like Limits

other than that it just applies torque

@timid dove Indeed it does add up.

[timid dove]

eyyy

[distant coyote]

even on kinematic objects

screenshot thingy comin

bottom is kinematic RB

[pale geode]

What are the numbers?

[distant coyote]

collision.impulse.y;

[pale geode]

Ohh

[distant coyote]

each object has a mass of 1

timeStep is locked to 0.01

and gravity is at -10

(to make them easier to read)

impulse obviously understands deltatime so you need to account for that to get "Weight"

[pale geode]

Why does it go from - 0.3 to +0.4

?

[distant coyote]

it represents corrective forces

not weight

[pale geode]

Ahh

Ok, thats cool

[distant coyote]

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEditor;
public class CollisionTest : MonoBehaviour
{
    float lastKnownMassLoading;

    private void OnCollisionStay(Collision collision)
    {
        lastKnownMassLoading = Mathf.Abs(collision.impulse.y) / Mathf.Abs(Physics.gravity.y) / Time.fixedDeltaTime;
    }

    private void OnDrawGizmos()
    {
        Handles.Label(transform.position, lastKnownMassLoading.ToString("f4"));
    }
}

for the edge case that this actually fkking works in 😛

for a more robust one...you'd probably want to keep a tree of everything you're currently colliding with, its Center of Gravity, etc.

after that its Physics 101 math

or be extra lazy, and put a trigger volume above your "Breakable" 😛

[pale geode]

Well, idk how ill do it, but im happy to know unity works like this

Thanks man

For showing me

[timid dove]

I'm actually really surprised this works and works so well

Kinda gets my game design juices flowing too

Nice job putting that demo together

[distant coyote]

yay physics 😄 lol

and now for the physics noobs, whats the difference between Mass and Weight? 😛

[calm plank]

If I recall high school, weight is a measure of the effect of gravity on a mass.

[wraith junco]

Bold of you to assume I attended high school

[calm plank]

lol

[stuck bay]

Wowwwwwww

ok

[main socket]

Hey guys, I have a Raycasting question:

I want to shoot a ray through multiple gameobjects until it hits a desired tag

currently the raycast is returning the first tag it hits, and i have to cast a new ray from this position

Is there a way to shoot a "continuous ray" until the desired tag is returned?

if (Physics.Raycast(currentSquare.transform.position, transform.TransformDirection(Vector3.left), out leftOfCurrentSquare, Mathf.Infinity))

i then have another IF nested within this one, which never triggers because the raycasthit tag is not "terrain"
if (leftOfCurrentSquare.collider.gameObject.tag == "terrain")

oh and is there a way to do this without using a layer mask?

[supple sparrow]

Well that's what Layer Masks are for

[timid dove]

RaycastAll will not stop at the first object

It will give you an array

But yeah if you want to go for a specific type of thing with the raycast you normally use LayerMask

Or even Collider.Raycast if you already know the specific object you're looking for

[pale geode]

Does anybody know why when I change the iskinematic flag of a GameObject to false it teleports into the ground instantly

?

Into the same position of the ground no matter where it is

after unchecking isKinematic as you see it just teleports into the ground there

the same thing happens when I change the flag with code

[pale geode]

I think I might have figured it out

My object has a hinge joint which seems to connect automatically to a point in the air?

which is set to the point in the floor

Yup, that was the problem

didnt realise Joints needed to be connected to something always and will connect to the air if no rigidbody is specified

[timid dove]

ah yeah

I've had that problem before 😄

[hidden wadi]

So i am making a physics based truck game and my truck keeps on rolling

[distant coyote]

move your CG down to the base of the truck

[hidden wadi]

cg?

this is what is happening

[distant coyote]

oh jeez lol

http://angryarugula.com/unity/teaching/Physics/CarExample.unitypackage

here

[hidden wadi]

thx

okay so i downloaded the code and draged it to my car

but i cant assign the tires to anything

[distant coyote]

check the demo scene

[timid dove]

lmao

sorry to laugh but that's hilarious

[patent sluice]

How do I stop a ScreenPointToRay physics raycast going through UI elements? From googling around it seems like there's not much built-in way of doing this easily, despite it being something I'd expect being a pretty common problem?

The only potential solution I've found is to call EventSystem.current.IsPointerOverGameObject() before doing the raycast to determine if the cursor is over a UI element - but this doesn't work for me, presumably because I'm using the new input system

I could just deactivate my targeting system when things like the ESC menu are opened, but that wouldn't stop rays being cast through HUD elements etc. So a custom solution would require a lot of checks - surely there's an easier way?

[pliant temple]

I have a question - is anyone familiar with Wheeljoint 2d Motor inputs? Like what do these values mean is it distance units per second??

[tawdry crown]

Hi everybody , I have a question, is it OK if multiple colliders as children of the same gameobject intersect with each other? Like this:

[timid dove]

It's fine

[tawdry crown]

Thanks!

[vernal tulip]

Help pl0x?
I have a jumping mechanic in a platformer, but I have a weird case that SOMETIMES when starting a jump while running into a wall, the velocity of the jump will be substantially lower the first fixed frame after the jump started.

More specifically, I'm calling add force on fixed update:
Player.Rigidbody.AddForce(i_JumpDirection * JumpForce * JumpForceModifier, ForceMode.Impulse);

Then in the next frame in fixed update I debug the velocity of the jump.

A proper jump (While not holding sideways against a wall) would result in a velocity of magnitude 16 for instance.
While holding into the wall though, it would sometimes result in the same value, which is what I want, but sometimes it will end up immediately on 10 in the frame after the jump starts.

Between the FixedUpdate where the jump's force is added, and the next FixedUpdate where it's monitored, there's a single tick of Gravity applied.
I manage gravity on my own with:
Player.Rigidbody.AddForce(gravity, ForceMode.Acceleration);
And have Unity's built-in gravity disabled.

No other physics force is applied other than those mentioned.
Is there an automatic drag that applies when grinding against a collider or something?

Any ideas? Suggestions?
Any help would be much appreciated.

[timid dove]

Unity does simulate friction

You could try adding PhysicMaterials to your colliders with zero friction

[vernal tulip]

Oh. That's an interesting suggestion.
I'll give that a try. Thanks!

This definitely seems to do something.
The first frame's velocity is now at 13, so the friction was probably indeed what was going on, but it looks like just setting it to 0 wasn't enough.
The way I was getting stopped before was more sharper, and now it just looks like a lower jump.
Is setting the dynamic friction and static friction to 0 enough to eliminate the friction calculations?
I left the friction combine as the default of average, does this value matter at all if the friction is already set to 0?

It looks like it did. Changing it to minimum now eliminates this problem for me.
Is it just my imagination though, or is this value actually doing something? It's a bit hard to tell from experimentation since this behavior was non-consistent to begin with =\

[timid dove]

so the default physics material has some friction value

if you have a material with 0 friction and set it to average

then the result will be half of the friction of the default

which explains why you're getting 13 instead of 16 or 10

then when you set it to miniimum

it's taking the minimum of the two friction values

so 0

[vernal tulip]

That's fantastic. Completely solved my issue. Thanks so much 🙂

[pale geode]

Is it ok to have multiple joints on the same GameObject, for an example multiple fixedJoints connecting to different gameObjects?

Hmm, it seems no :/

One ends up not accepting a rigidbody to attach to

[pale geode]

Huh, i got it to work now, that wasnt the problem

[viral apex]

Any thoughts on why my character gets stuck here?

I tried changing the size of the upper collider. But it still happens

[foggy rapids]

the error may be in your input/movement code depending what you mean by stuck

generally people get stuck due to corners colliding. And you solve that by not having corners or using circle collisions

[edgy solstice]

Hello, can someone help me with constraints on rigidbody, I've applied constraints on rotation X and position Y but when i collide with another objects those constraints are not working.
The more I collide the more my object gets pushed on those axis.
Is there a way to prevent this from happening, and explain me why is it happening?

[timid dove]

Can you show a video? That shouldn't happen

[edgy solstice]

@timid dove
Here it is, but i think i managed to prevent this by locking the rotation on Z axis as well

Not sure why it's not working if only X rotation is locked

Every time i collide it tilts on X axis

[timid dove]

Gimbal lock

Probably? Not sure

[edgy solstice]

Hm i don't know

[edgy solstice]

you might be right

[viral ginkgo]

@edgy solstice a quaternioun rotation can be equal to infinite euler rotations i believe

if you try to read transform.forward.y, i believe it should be constantly 0

[cedar hull]

how do i make this cup pushabl

[viral ginkgo]

@cedar hull add rigidbody

[pliant temple]

hello help

what is the unit for motor force in 2d?

[cedar hull]

it has one

[viral ginkgo]

ah, my bad

it should move then?

and you can push it if you walk into it with that character

[cedar hull]

it doesnt do that though

[viral ginkgo]

your character has a collider?

[cedar hull]

yes

[viral ginkgo]

@cedar hull maybe its got a trigger collider on?

[cedar hull]

whats that?

[viral ginkgo]

theres an option in collider

"is trigger"

[cedar hull]

its not on#

[viral ginkgo]

it should be off

no idea

thats odd

[cedar hull]

could it be because its still packed from importing?

[viral ginkgo]

nope

whatever values you see in inspector, they are whats being used

maybe the character moves visually but collider doesnt?

maybe you have root motion movement or something in child

@cedar hull see the collider that it actually moves when you move the character

[cedar hull]

I carnt walk through walls so im guessing it does

[viral ginkgo]

drop another rigidbody cube on top that cup

@cedar hull

[cedar hull]

k

[cedar hull]

and it does

https://gyazo.com/f204efc6dc92b6911a19d4171b251431

[viral ginkgo]

drop a cube on top that cup

in an angle that will move the cup

or make the cube heavy

to it moves the cup

[cedar hull]

i carnt move either

the player needs a rigid body?

[viral ginkgo]

the cup wont move when its colliding with another cube?

@cedar hull a rigidbody can collide with a non rigidbody collider

although if the cup is in sleeping state, maybe collision is being skipped

[cedar hull]

idk if this helps

but when i walked to teh cube

i went inside it

the same thing doesnt happen with the cup though

[viral ginkgo]

if plan on pushing things around with your character, maybe its better if you have a collider on your character

but i remember you already had one

so i dunno

[cedar hull]

ill try add a 2nd colider see if that works

[viral ginkgo]

maybe you changed project physics settings

i dunno

[cedar hull]

ill check

[viral ginkgo]

i'd check the collision layer matrix

[cedar hull]

the what

@viral ginkgo

[viral ginkgo]

it looks fine

i have no idea

should try to drop a cube on top of the cup

so you know if theres something wrong with physics

[cedar hull]

k

they work with each other ;-;

could it be a problem with the char control script?

[viral ginkgo]

@cedar hull Maybe you just need to control the character via rb.velocity

but i am not sure about it

[cedar hull]

i dont see a reason they shouldnt work they can colid with each other but there like stuck when it comes to the player model

[undone isle]

Hello, is there any way to prevent a collider from automatically attaching to a rigidbody component in a parent gameobject? Working specifically with 2d.

[viral ginkgo]

colliders parented to a rigidbody automatically becomes that rigidbodys collider

[undone isle]

Yes, I want to disable that if possible 😄

guessing not though

[viral ginkgo]

why anyways

[undone isle]

I have two gameobjects, gameobject1 is a parent to gameobject2. 1 has a rigidbody and 2 has a temporary collider I am turning on during an attack. I want this to interact with particles, but OnParticleCollision only gets called if it's in a script attached to gameobject1, not 2. But I prefer the script to be attached to 2.

[viral ginkgo]

you could maybe call a delegate inside OnParticleCollision to wherever you want that to be handled
or a function

[undone isle]

The attack is also a "spin" style of attack, and I want the player graphic to appear as though it is continuing to spin even if the attack collider has hit a rigidbody that would prevent it from continuing to move in a direction. With the collider automatically attaching to the rigidbody, some weird separations are occuring with other joint attached rigidbodies

I'm feeling like I'm just using the physics system incorrectly here

[viral ginkgo]

i am not experienced with particles anyways, maybe somebody else will have a better answer

[undone isle]

I appreciate it

[fair scaffold]

morning

I had a question on hinges

is there a way to restrict axis on a hinge

so local rotation is restricted?

I made this hinge for the chamber of a gun. It works pretty well but you can push it in weird angles if you do your best.

[wide root]

Reset the velocity

I had the same issue, wanted to constrain to a local axis but constraints are applied in world space

I found I could essentially lock any axis by resetting the velocity of the body, keeping it from moving in undesirable axis

I used it for dynamic handle sliding, similar to that of B&S to prevent it moving with the hand while it reapplied the offset

Yes it will still move with the connected anchor*

But it should fix that issue locally relative to the parent

Or well, connected body

[cunning terrace]

hey , im using a particle system and added colliders to them , but they are not centred properly is there a way to fix this?

[cunning meteor]

so im using Unity Physics and spawning in a bunch of cubes with Physics Bodies and Shapes that is set to 1,1,1

and they are all right next to eachother

but for some reason they are not staying still and are falling

which shouldnt happen as there is no way they can be pushing eachother

    private void CreateTower()
    {
        foreach (var entity in _entities)
        {
            _manager.DestroyEntity(entity);
        }

        _entities.Clear();

        for (var h = 0; h < height; h++)
        {
            for (var w = 0; w < width; w++)
            {
                for (var l = 0; l < length; l++)
                {
                    var entity = _manager.Instantiate(_towerEntity);

                    var objectTranslation = new Translation()
                    {
                        Value = new float3(l, h + 0.5f, w)
                    };

                    _manager.SetComponentData(entity, objectTranslation);
                    _entities.Add(entity);
                }
            }
        }
    }

[supple sparrow]

Since they are all falling you probably have gravity set

If your towers aren't supposed to move, remove the Physics Body component on them

[cunning meteor]

they are meant to be using physics and they are supposed to move

but they are level with the ground when spawned

so they shouldnt just move

the gound does work

basically the outer layers move a little somehow

and the rest of it follows

[supple sparrow]

I dont understand your setup and whats wrong with it. Can you screenshot the cubes in the scene view ?

[cunning meteor]

@supple sparrow

why does discord not allow mkv files

hold on

[timid dove]

They're slightly colliding with each other

And being pushed away

[cunning meteor]

how though

they are all 1 bty 1 by 1 cubes

[timid dove]

The physics engine is simply not perfect

[cunning meteor]

ok

how would i add slight spacing then

[timid dove]

Maybe add .001 space between them

[cunning meteor]

hmmm

yeah im thinking how to do that

in that loop

[timid dove]

Multiply the position Vector by 1.001

[cunning meteor]

oh

why did i not manage to think of that

also just as i side question but do you think havok physics would be able to properly handle this?

im not switching if it can

[bright lagoon]

I assume most physics engines would dislike simulating a bunch of objects that are "0" distance apart.

[cunning meteor]

yeah

yeah it helped

the height it the only issue now

[supple sparrow]

Maybe try to also increase friction

[dense belfry]

how can i calculate the radius of a planets gravity ?

i thought about using this formula f(x)=a/x f(x) = distance, x = G, and i don't know what to put in <a> . i want to use this formula because of the graph cause the bigger the x the smallest the distance and the opposite

BUT: lim f(x) ( x -> 0+ ) = +infinite and lim f(x) ( x -> 0- ) = -infinite so the lim f(x) ( x -> 0 ) = doesnt exist

lim f(x) ( x -> +- infinite) = 0

can plz someone help my brain hurts xd

tho i wont use any negative numbers so i don't care about the -infinite so lim f(x) ( x -> 0) = +infinite

a = radius

sorry if i spam

this can't work cause it's meters/m^3 kg^-1 s^-2 = meters XD

found it

if anyone else want's it it's r=(G*M)/c^2

[west shard]

float timeForMaxHeight = jumpVelocity / Physics.gravity.magnitude;
maxPlayerJumpY = jumpVelocity * timeForMaxHeight;```

im trying to get the max Height of a object which i give a y Force to

but this code doesnt give me the exact height

the red line shows maxPlayerJumpY but the object doesnt reach it

any ideas how I can solve this problem?

[timid dove]

jumpVelocity / Physics.gravity.magnitude;

maxPlayerJumpY = jumpVelocity * timeForMaxHeight;

this is not how motion with acceleration works...

the player will not be travelling at the same velocity for the whole duration of the jump

You need to use the projectile trajectory formula

https://www.omnicalculator.com/physics/trajectory-projectile-motion#:~:text=Trajectory formula,-Now as you&text=x %3D Vx * t,t - g * t² %2F 2

[torpid temple]

I'm having trouble making this chip collide with my pegs board. The pegs have rigid bodies and capsule colliders. What should I do?

[civic pike]

ouch

sad

Vin

[torpid temple]

pardon?

[civic pike]

nvm

[timid dove]

show the peg colliders?

[timid dove]

kinda hard to tell from that screenshot where the actual bounds of the capsule are

make sure it's lined up with the peg graphic itself

also does it help anything if you cahnge the collision detction on your poker chip to Continuous?

[torpid temple]

Sorry about that

[timid dove]

yeah that looks fine

[torpid temple]

it does not, shows the same result

[timid dove]

try making your mesh collider convex on the chip

also what did you change the cooking options to

[torpid temple]

I don't believe I changed it

[timid dove]

dont make it a trigger

only convex

[torpid temple]

This is what happens if I dont and if i turned on capsule collider

[timid dove]

uhh

The cylinder mesh you're using...

is it the default unity one

or one you made in blender?

[torpid temple]

It is, the default capsule collider caused what happened in the video and mesh seems to work, but it isn't colliding with anything

[timid dove]

something's really fishy with your collider

[torpid temple]

I do have a physic material added to the mesh collider but I doubt thats the problem

[timid dove]

shouldn't be the problem

it seems almost like your capsule collider is centered way off center of the object

I see the center position for the capsule collider is some really big or really small number

cant tell because it's cut off

[timid dove]

ok yeah those are both basically zero

should probably just set them to zero

[torpid temple]

done, no change

[timid dove]

you haven't played with any of the physics settings in the project settings have you?

especially the collision matrix?

[torpid temple]

I have not, I simply started making the board from primitive shapes and put colliders on the pegs

[torpid temple]

I have not touched that either. I just moved the chip inside the board under the pegs and this happened

@timid dove Hey man I figured it out, it was the table all along because of the capsule collider 🥴 thanks for the help!

[gilded sparrow]

Hi all a simple question:

Im making a multiplayer board game with dice
The dice roll will be in its own "container", the players can see it too
I'd roll in the server first, and given the same initial pos/rot/force, all clients should get the same result deterministically, right?
Any further steps to ensure that? Like doing the dice roll its own physics world, etc?

[timid dove]

Ehhh not necessarily

Floating point calculations may have different results on different hardware

Just ask @wraith junco about it he's been struggling with that

[wanton tendon]

i tried doing an car with an tutorial but the wheel collider ignores the ground
in the video the car stands on the wheels/colliders but here they are in the ground

[timid dove]

I would do something a bit different. Maybe use a bunch of prerecorded rolling animations or presimulating the dice roll so you know which side will land up then paint the decals of the dice roll on after :)

[marsh raft]

E=mc^2

[timid dove]

Double check that your Colliders are in the right place

[wanton tendon]

they are.... i think maybe im just dumb @timid dove

[gilded sparrow]

So for worst case, i reckon just sending the simulation snapshots would be most accurate, but then again... it's only for dice roll visuals so why should i bother, right?

Unless there's other way to send dice roll physics sim snapshots

[quick night]

for the sake of my game design, i had to program gravity on some objects myself. it is working perfectly, except it keeps getting inserted in the ground at random depths. i tried switching its collision detection to continuous but doesnt work. here is a demo for it

https://youtu.be/ZBio0FmdPVM

if required, i can send the code

[dense belfry]

am i allowed to flex?

[lofty turtle]

hey guys, quick question, how do i set the rotation of a gameobject(sprite) 90/180 deg left/right (using quaternions)?

im trying stuff like quaternion.euler(0,90,0) etc but the results are not what they're supposed to be

[timid dove]

Make sure you're rotating on the correct axis. Normally you would rotate a Sprite on the z axis if it's a 2D game

[wraith junco]

@gilded sparrow From what I've seen, most calculations are off by about the thousandth to ten thousandth decimal

even on the same hardware

with the same exact forces applied

If you're doing physics over a network, you're probably going to want to do lockstep. Which is easy. Just don't run physics on the client, just grab the positions/rotations of the physics entities from the server and lerp the model's position to it. This is how the game "Rust" does their multiplayer physics.

I'm in the process of changing my main character from a rigidbody to a character controller because the reconciliation events are extremely expensive even for one rigidbody

causes massive lagspikes if you don't have a high enough fps

[kind obsidian]

Thoughts on using a 3D collider on a 2D game? Since I will have flying monsters, projectiles that might be ground-based (e.g. earthquake, ground attack, wave/flood) and some monsters might not fly etc. Or should I add 6-7 extra layers to support this? Anyone did it before? Guess I might have to do a mass refactoring from 2D colliders to 3D -_-

[foggy rapids]

it's very common practice.

but you have to use one or the other. You can't use 2d physics with 3d colliders, but you can make a 2d world using 3d physics

[lofty turtle]

i got around it just using transform.Rotate(), thanks anyway!

[gilded sparrow]

Its only for client side visual. Lockstep n anything is already waaay overkill for a dice roll visual

Actually the last option i thought of yesterday is, make its own physics world scene, client receive the values from server, then set the dice already facing the correct values upside

Then manually do Simulate for 3seconds worth, with the first frame blasting addforce to it.
Save the per frame snapshots
Then play it backwards

[wraith junco]

That's going to kill your performance if you're manually simulating physics and doing reconciliation with that

I would extremely recommend lockstep for this approach

games like Rust don't have prediction on ANY of their vehicles because it would just cost too much to do the reconciliation

on the CPU

[crystal iris]

It sounds like they don't need to do reconciliation?

[wraith junco]

I'm still lost on what he's trying to achieve

[crystal iris]

To me it sounds like they need the server to determine a dice roll result, and then have the client's represent that dice roll result with a physical dice roll

If you want the rolls to be exactly identical yeah you'll need some kinda lockstep or something. But if all that matters is the dice showing (6,6,1,3,6), then they don't need the physics to be networked

[wraith junco]

unless theres the 1% chance that the dice falls the wrong way

[crystal iris]

But they would need a way to "fake" physically rolling dice that land on pre-determined values

[wraith junco]

onto the wrong side

[crystal iris]

Well yes, that's why you wouldn't truly physically simulate the dice on the clientside

[hexed stream]

Question, I have all of the physics for a skiing game, although I don't know how it should be moved. I have tried using acceleration and force from the AddForce in the forward vector but that didn't work because it doesn't count for turning. Any ideas?

[wraith junco]

You can't rotate a rigidbody or it's going to jitter.

You need a rigidbody, and then some child without a rigidbody that does rotate

then move the rigidbody in whichever way the child is facing

[crystal iris]

You can rotate the rigidbody and still obey the physics simulation by using Rigidbody.AddTorque

[wraith junco]

That doesn't give you a very accurate rotation

im talking about precision

like first person controllers

[crystal iris]

And plubos is talking about a skiing game

[wraith junco]

true

[hexed stream]

Although if I use a child for rotation without a rigidbody, the rigidbody on the ski would be pointless

It would just be a big hassle

[wraith junco]

the rigidbody would absolutely not be pointless

the rigidbody doesn't hold the model

the child does

the parent is literally a rigidbody with a collider

no model

[hexed stream]

Oh thats what you meant

[wraith junco]

the child just dictates which direction you apply force at

on the rigidbody

Im not that advanced with physx, but you probably could just put a rigidbody on the parent without a collider, then put the collider on the child

that way the collider rotates

not sure if that would work, probably will

child also holds the camera

[hexed stream]

The parent does need a collider though or else it will just fall if it isn't holding the mesh

[wraith junco]

if the child has the collider it wont.

at least I think

[hexed stream]

No

cant mark it kinematic either

[wraith junco]

kinematic would be useless if you're doing physics movements.

[hexed stream]

yep

[crystal iris]

The parent rigidbody will utilize any child colliders as it's own

[distant coyote]

until it sees another rigidbody in the hierarchy. think of it like "Dividers"

[kind obsidian]

Thanks. Time to refactor =[. I'll research the performance implications but I guess I got no choice if I want a complex game with different "heights" in my 2d game

[kind obsidian]

hmm, there's no "3D" tilemap collider though 😦

I'll spend a few weeks thinking about whether to use "10" extra layers called something like "FAKE_3D_{HEIGHT}_{OFFSET}"... or to use 3D colliders. The lack of support for 3D tilemap colliders on my 2D tiles made me not go for the 3D collider solution =[

[quick night]

for the sake of my game design, i had to program gravity on some objects myself. it is working perfectly, except it keeps getting inserted in the ground at random depths. i tried switching its collision detection to continuous but doesnt work. here is a demo for it

https://youtu.be/ZBio0FmdPVM
if required, i can send the code

[crystal iris]

Are your wall colliders set to be static?

[quick night]

no they are not static

[foggy rapids]

Yeah but it's still possible.
I use a grid component and cube meshes with their textures mapped in world space.

[kind obsidian]

oh ok, I'll learn about Meshes and textures, since I mostly have experience in 2D

[lethal wyvern]

Hi guyz! Am making a rigidbody FPS movement but i have a problem with stairs and slopes when going down

i tried a mass of 100,000 but that didnt help

for Movement am using Rigidbody.Velocity()

What do i do ???

[kind obsidian]

uh i don't quite understand, so i'll still need a 3D Tilemap system though right? https://forum.unity.com/threads/free-3d-tilemap-system-for-3d-pixel-art-games.710600/

[foggy rapids]

sure

whatever gets the job done

[timid dove]

explain your problem please. You said you have a problem but not what it is.
also share how you are moving your character

[kind obsidian]

ah ok, i'll spend a month thinking about using 3D colliders vs using the Layers collision matrix thing with 2D, cause its quite a massive refactor/decision

[foggy rapids]

if you are already committed to 2d phsics then just go with layer collision matrix

or z-sorting or whatever

[kind obsidian]

true.. i'm also tryna think if there's a way to call "Physics.IgnoreCollision" before the "OnCollision" is triggerred (and before rigidbody takes into account collisions too), so i can add my own custom logic to compare the Z min/max values

guess collission matrix it is, but will wait a month in case i find a better solution for my use case

[wraith junco]

So say I wanted to make my own "Rigidbody" car, with it's own wheels and everything completely without using physx, how much of a shit show am I in for?

And would I need any advanced math to do so?

I'm not looking for hyper realism, just something predictable over a network

[foggy rapids]

ur in for a big shitshow

[wraith junco]

yikes

[foggy rapids]

making the car move is the easy part. Doing collision detection is the hard part. Networking the whole thing is the hardest part.

[wraith junco]

I got my lockstep cars working with physx and tested it over a network, and the delay was awful

so that's my main concern

If you could physics.simulate individual objects, that would make life so much easier

That's literally the most important thing they left out

[foggy rapids]

lol, i think that would make it more of a mess

[brittle sluice]

Hey everyone, Im working on ragdoll physics and im having this weird bug, I've looked around to see if anyone else had the issues on the forum but no answers so I joined the discord! 👋 [Gif is down below as well]

I have a guess that something with the animation is possibly changing the position of each bone, but not 100% sure.

[brittle sluice]

Its causing the ragdolls when I hit with a stick, they hit the ground right underneath them hard and fly super high in the air.

[viral ginkgo]

Just set all objects kinematic except the one you want to simulate?

[wraith junco]

Then you have to go through each one and re-apply the velocity and every property it had that the kinematic took away

sounds like a huge mess

Have you done it that way before?

[viral ginkgo]

i never really needed to simulate one objects seperately from others

when i didnt wanna simulate other objects, i kept them kinematic forever

[wraith junco]

reconciliating even one object takes a bunch of CPU anyways

causes huge spikes in the profiler

[viral ginkgo]

if your game doesnt do any prediction, maybe you should just go with snapshot interpolation instead of lockstep

[wraith junco]

What's the difference between snapshot and lockstep

I think I might be getting them mixed up

[viral ginkgo]

snapshot interpolation: server sends position, rotation only
client doesnt simulate anything, (i am saying you also may not need to simulate local player)

lockstep in general: fully deterministic simulation, no positions/rotations/velocities etc sent from server.
server sends all client inputs to each client
clients simulate everything, no prediction, no rollback

rollback: lockstep but it predicts the future, no local player input delay

@wraith junco

[wraith junco]

So how my cars work is, every tick from the server, they get the position, rotation, and inputs

so first snaps to correct position, rotation, then it "drives" the car for that tick

otherwise it just doesn't look nice

but yeah my main character is fully predicted and does use rollback

[viral ginkgo]

so you did lockstep but also with state syncing to compansate for non-existing determinism

and rollback for local player

[wraith junco]

yes

[viral ginkgo]

but the thing is, do you really need to simulate other cars if you dont need to predict them?

[wraith junco]

If you don't apply motortorque and wheel steering, it doesn't feel nice at all

[viral ginkgo]

purpose of lockstep is saving bandwidth

but you already send position/rotation

@wraith junco i mean the other cars from remote players

[wraith junco]

wym other cars

[viral ginkgo]

i wouldnt simulate them at all

[wraith junco]

none of the cars at all are predicted

even the player driven car

[viral ginkgo]

but they are simulated

[wraith junco]

yes.

If you just apply position/rotation, the movement feels blocky as hell

you need to apply wheel steering too

and motor torque

[viral ginkgo]

you said you predicted local player?

[wraith junco]

yes

[viral ginkgo]

why does the feel matter for remote players?

[wraith junco]

The local player is predicted on foot

not in the car

[viral ginkgo]

ah

[wraith junco]

physx wheel colliders are not deterministic in any way

every single input will ALWAYS produce a wrong movement

for some reason

[viral ginkgo]

you cant reconsiliate wheel speed

if you are not predicting lcoal player, you should not need to do any simulation

[wraith junco]

try it for yourself, only interpolating position/rotation just doesn't feel right

simulating the car for that tick makes it feel so much better

and then the lerp smoothes out the wrong position

[viral ginkgo]

i will assume that you are sending about 10 transform info per second?

[wraith junco]

around 20

no wait

50

I send data every fixedupdate

[viral ginkgo]

what kind of lerp are you doing?

[wraith junco]

lerping model to the actual rigidbody

so its always lerping

[viral ginkgo]

regular vector3 lerp?

[wraith junco]

yes

[viral ginkgo]

Vector3.lerp(current, target, deltatime * something)?

[wraith junco]

yes

[viral ginkgo]

i believe thats your issue

[wraith junco]

how so?

[viral ginkgo]

you can do a smarter lerp so that it always outputs the correct position the car needs to be in with a little delay

[wraith junco]

even then, simulating the car's rigidbody provides somewhat of an extrapolation

an accurate extrapolation

[viral ginkgo]

you buffer transform infos with timestamps

and then you look into the buffer

lets say you wanna see where car should be in 10.0

you have a pos0 with timestamp 9.48
and a pos1 with timestamp 10.32

Vector3 interval = Mathf.InverseLerp(9.48, 10.32, 10.0);
currentpos = Vector3.Lerp(pos0, pos1, interval);
@wraith junco

thats the smart lerp if i didnt make a mistake

[wraith junco]

damn that sounds like a lot of extra work

is there any real downside to simulating the rigidbody every tick?

[viral ginkgo]

dealing with nondeterministic behaviour

and physics

[wraith junco]

right, but the non deterministic behaviour is corrected every tick

and is already smoothed by the lerp to the point where there's no jitter to be found

Your method might even introduce a little bit more delay

I think that's what garry's mod does with their serverside cars, and I'll tell you that the input delay is awful

on gmod

[viral ginkgo]

i offered this because you said you werent doing any big predictions, only one frame of prediction

might as well go with no prediction at all

[wraith junco]

hmmm

maybe

[viral ginkgo]

you will never have any smoothness problems and things will play out pretty much %100 same with server

since you also send data for all fixedupdates

[wraith junco]

I'll do some further testing, if my method doesn't work then I'll definitely go with yours

I'll send you a quick vid of how the cars look

https://streamable.com/4xhg4i

@viral ginkgo

[viral ginkgo]

your player character looks a bit fat for the car

[wraith junco]

100%

just testing for now, fancy stuff comes later 😉

[viral ginkgo]

thats what happens in server tho

it looks like it would go michael bay style if this whole thing is reconsiliated and predicted lol

[wraith junco]

reconciliation doesnt happen in cars

[viral ginkgo]

yeah yeah

[wraith junco]

it literally gets turned off completely if you're in a car, no way for it to happen

wym by it being too fat though?

[viral ginkgo]

i was just kidding about the fat cylinder

[wraith junco]

oh haha

[hot jackal]

Hi all!
We are facing a little problem with the drag simulation for particle systems.

We have a logical data structure that represent a bullet that fly with a specific velocity.
In a separate class we are configuring a Particle System according to gun's data, so we are sure that particle will be aligned to the physical bullet.

It's all fine until we have introduced the drag.
Following the rigid body drag model, we have applied a drag like:

V(n) = V(n-1) * (1 - Drag * dt)

If we set the same drag value on the particles, the physics object and the particle seem to evolve differently.
So the question is: which drag model is actually used for particles?

[stuck bay]

Can i link multiple rigid bodies to one so they behave as if they were parented?

[viral ginkgo]

@stuck bay if you add a child collider to a rigidbody, that collider will do what you want

it will basicly become its parent rigidbodys collider

[stuck bay]

Thanks