Changing RotationalMotor target angle at runtime not working with Havok

Physics
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1

I’m doing some experiments with the rotational motors from the EntityComponentSystemSamples. I would like to control the target angle of the motor at runtime.

I setup a scene with a static box and a dynamic box like the example with a joint, which I control with this system for testing:

    [UpdateInGroup(typeof(BeforePhysicsSystemGroup))]
    partial class MyMotorSystem : SystemBase
    {
        protected override void OnUpdate()
        {
            Entities.ForEach((ref PhysicsJoint joint) =>
            {
                float target = 0f;
                if (Input.GetKey(KeyCode.Space))
                {
                    target = -math.radians(45f);
                }

                if (joint[0].Target.x != target)
                {
                    Debug.Log($"Changing target to {target}");

                    var constraints = joint.GetConstraints();
                    var constraint = constraints[0];
                    constraint.Target = new float3(target, 0f, 0f);
                    constraints[0] = constraint;
                    joint.SetConstraints(constraints);
                }

            }).Run();
        }
    }

It works with UnityPhysics, I can see the box rotating on a side by 45 degrees when I press Space, and go back to 0 degrees when I release Space.

However I tried switching simulation to Havok, and it stopped working, the box doesn’t move. If I run the original Unity example, motors do rotate to their target angle, but that angle is set at authoring time. I don’t understand what I’m missing in my code in order to change that target at runtime using Havok, when it otherwise works with UnityPhysics.

2

I think I figured out what happens:
Turns out with Havok, sleeping is enabled by default, the motor somehow was sleeping on startup, and changing joint constraints doesn’t awake bodies.
If I add HavokConfiguration to the physics settings and disable sleeping, the test works as intended…