3D Rigidbodies falling through ground and acting buggy

[rugged crag]

For some reason the rigidbodies in my game glitch around and phase through walls randomly? I'm pretty sure there's nothing in their code that would cause them to do this but I'll just post it here anyways

extends RigidBody3D

@export var carrying = false

var carrier : Node3D = null

@onready var offset = $CollisionShape3D

@onready var originalParent : Node

var carrySlotID : int = 0

func _ready() -> void:
    originalParent = get_parent()

# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(delta: float) -> void:
    if(carrier != null && carrying):
        position = Vector3(0,1 + offset.scale.y * carrySlotID,-0.5)
        
        rotation = Vector3(0,0,0)
        
        linear_velocity = Vector3(0,0,0)
        
        if(Input.is_action_just_pressed("Drop")):
            reparent(originalParent)
            carrier.amountCarrying -= 1
            carrying = false
            carrier = null
    
    var touchers = $Area3D.get_overlapping_areas()
    for i in touchers:
        _check_area(i)


func _check_area(area: Area3D) -> void:
    if(area.is_in_group("Player") && area.get_parent().is_multiplayer_authority() && !carrying):
        if(Input.is_action_just_pressed("Depositing")):
            carrier = area.get_parent()
            carrying = true
            
            var modelPropNode = carrier.model.props
            
            reparent(modelPropNode,false)
            
            position = Vector3(0,1,-0.5)
            
            carrySlotID = carrier.amountCarrying
            
            carrier.amountCarrying += 1
            
            print(carrier.amountCarrying)

I should mention too the area is all a csgcombiner with collisions so if that causes issues that'd make sense

[rugged crag]

can someone help-

[short spire]

First, if you haven't already, open project setting, find physic 3d category and change physic engine from Default to Jolt

[rugged crag]

Ah yeah I've been recommended jolt before so that should fix some of the issues, thankfully the only rigidbody in the whole game is these ones so it won't cause any major issues

[merry anchor]

Setting the position of a rigid body manually is always asking for trouble. My guess is the discrepancy between what the physics engine is expecting and the manually set positions eventually resulted in a glitch.
Try using _integrate_forces instead.

[rugged crag]

What does integrate forces do?

[merry anchor]

I'll let you read more about it in the docs, but basically it lets you safely set the position of a rigid body without the physics engine complaining about it

[rugged crag]

Ahh ok

Ill try it out and if thay doesn't fix it I'll use jolt3d

[merry anchor]

Ah, you should use jolt either way lol

[rugged crag]

So true

[blazing hatch]

I would either freeze the Rigidbody while you're carrying it so you can set position and rotation without any physics issues
Or use physics to keep that Rigidbody in position by constantly applying forces/setting velocity.
With the first solution the Object wont interact with the environment anymore, with the latter it will still collide with walls and such but is not really fixed to that carry offset position.

IntegrateForces has its uses but not really necessary here.

And absolutely switch to jolt before doing anything else 😉

[rugged crag]

I should prob do the latter because I don't want ppl shoving these into walls and clipping them out of bounds 😭

[rugged crag]

so for some reason using reparent with jolt3d makes anything reparented just expand each time it's reparented??

[pulsar grail]

note that setting velocities directly in _integrate_forces is also fine

you just don't want to say the position and rotation directly if the body is not frozen

rigid bodies are controlled by the physics engine when they're not frozen

and for it to simulate them correctly, it needs to know their linear and angular velocity and move them based on that

[pulsar grail]

them increasing in size multiple times is probably a bug, but is anything not using default scale? rigid bodies don't work when scaled anyway, so the engine tries to fix their global scale automatically

[rugged crag]

the collision shape isn't

[pulsar grail]

the rigid body itself doesn't like to be scaled by anything

including parents

[rugged crag]

ok yeah it was the parent