Domain randomization seems CANNOT change rigid prims' restitution

Omniverse Isaac Sim
1

Hi,

I am working under OmniIsaacGymEnvs and trying the provided domain randomization code for the shadow hand task. I want to apply noises to object_view’s material properties, especially restitution, on reset. I randomize the restitution of objects in two ranges, [0.0, 0.1] or [0.9, 0.99], and launched two runs. However, the behavior of objects dropping to the ground seems identical.

More specifically, I have made the following modifications to the released code:

  • In the domain_randomization/randomization_params/rigid_prim_views/object_view/material_properties/on_reset of the ShadowHand task config:
    (1) set the operation to direct;
    (2) set the distribution parameters to [[0.7, 1, 0.0], [1.3, 1, 0.1]] or [[0.7, 1, 0.9], [1.3, 1, 0.99]].
  • In the task/shared/in_hand_manipulation.py, I register a GeometryPrimView for the ground plane, and apply a physics material with restitution 0.5 to it, during set_up_scene.

I launched two runs with the two different distribution parameters (one with restitution in [0.0, 0.1], and the other with restitution in [0.9, 0.99]). I printed object_view._physics_view.get_material_properties(), which is indeed some random value in [0.0, 0.1] or [0.9, 0.99], but the behavior of the simulation environment seems identical for these two different settings of object restitutions. When objects drop to the ground from the hand, none of these two restitution ranges makes the object bounce more than the other.

Why are there identical behaviors under different restitution ranges? I have attached the modified code below. Is there something wrong with it?

omniisaacgymenvs_restitution_dr.zip (287.6 KB)

3

Hi there,

thank you for the report, the Isaac Gym team is investigating the issue and will get back to you.

Best,
Andrei

5

Thanks for reporting the issue! The next Isaac Sim release will include a fix for this.