Deleting and generating prims for OIGE environment reset

[paula.gascla]

Hello, I have a question about environment reset using OIGE. So for the task I am setting up I have to spawn a new cube every x timesteps in an episode. Each cube is a DynamicCuboid generated in env_0, then cloned to all other environments and finally, all the clones are wrapped around a RigidPrimView (e.g. for all cube_0, the view is named cube_view_0).

The issue comes when resetting a specific environment. If at the end of the episode I’ve generated 10 cubes, the reset should consist of removing them all and spawning a new cube_0. However, with this approach 2 issues arise:

1. I am able to delete cube prims using the delete_prim() function of omni.isaac.core.utils.prims. However, when I delete cube_0 (as an example), the associated cube_view_0 is not removed. Therefore, when I want to generate a new cube_0 and its corresponding new cube_view_0 the following exception is printed in the terminal: “Cannot add the object cube_view_0 to the scene since its name is not unique”. Do you know of any way to also eliminate RigidPrimViews or a workaround for this issue?
2. More importantly, doing as described above, every time I delete a prim, the prim is simultaneously deleted in all environments, meaning I cannot perform independent environment resets. Is there any way of deleted and generating prims in specific environments while still taking advantage of the efficient memory usage of OIGE parallelization?

[kellyg]

Hi there, views can be removed from the scene using scene.remove_object() from omni.isaac.core’s scene.py. If you would like the environments to stay independent of each other, you can use the copy_from_source parameter when cloning the environments, with copy_from_source=True in the Cloner.clone() call.

[paula.gascla]

Hi, thanks for the response!

If I undertand correctly, the Cloner.clone() call you are referring to is in the set_up_scene() method within the omniisaacgymenvs>tasks>base>rl_task.py file, right? If so, that call does not have a copy_from_souceargument to be passed.

Do you have further guidelines on how I could set that flag or how to get my environments independent?

[kellyg]

The copy_from_source argument can be found here: https://github.com/NVIDIA-Omniverse/OmniIsaacGymEnvs/blob/main/omniisaacgymenvs/tasks/base/rl_task.py#L144 and passed when calling RLTask.set_up_scene(). The flag was introduced in the Isaac Sim 2023.1.0 release.

[paula.gascla]

Thanks, I was indeed using Isaac Sim 2022.2.1., that is why the flag was not available.