How to I apply torque to a rigidbody 3D?

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:bust_in_silhouette: Asked By DarkShroom

Many of = the previous functions have gone for adding forces and torque…

currently i can only use:

func _integrate_forces(state):

this is fine for normal absolute force

how do i apply torque? or rotational force that rotates an object?

:bust_in_silhouette: Reply From: Kyle Szklenski

You add torque to a RigidBody, not to the physics state of a RigidBody. There’s a function on RigidBody itself that you can call.

There is no function to add torque on the RigidBody itself. The closest would be set_axis_velocity, but it may not be the most convenient.

Zylann | 2018-11-15 18:58

:bust_in_silhouette: Reply From: DarkShroom

someone on the godot facebook group has confirmed it is coming for version 3.1


Strange, I was able to use torque in 3.0, it’s not missing^^
I implemented _integrate_forces and used the PhysicsDirectBodyState argument, it has a function to apply torque PhysicsDirectBodyState — Godot Engine (3.0) documentation in English.

If you need to apply torque from outside, you could make a variable that you set outside, and apply it when _integrate_forces gets called.

Zylann | 2018-11-15 18:56

:bust_in_silhouette: Reply From: SIsilicon

You know if there is no function to add torque, maybe you could emulate it.

func add_torque(state, torque_axis):
    var force_pos = torque_axis.cross(Vector3(0,1,0)).normalized()
    var torque = torque_axis.length()
    var force_dir = force_pos.cross(torque_axis).normalized() * torque

    state.add_force(force_dir, force_pos)
    state.add_force(-force_dir, -force_pos)

state is, well state. The direction of torque_axis is the axis your adding torque about. Its length defines the strength of the torque.

Note: I made this function on the top of my head. I haven’t tested it yet so bare with me.