[ISAAC SIM USD update] What "Prim or Xform" component is saving the robot base transform when using BaseEnv?

[Ltesfaye]

Question

I'm noticing that the robot movement is not tied to spawned primatives in Isaac sim for tutorial demos. I'm having difficulty identifying how the rendered robot movement ties into the spawned primitives and their relative transforms.

Specifically, when looking at orbit tutorials "create_quadruped_base_env," all the transforms are tired to initial grid spawn and never update with respect to the robot movement. Is there a method to call during each env.step() to update the USD file with the transform, or do we need to manually write the transforms to the stage using omni execute command?

If it is the second option, is there a recommended way of doing this so it does not interfere with orbit physics simulations?

So far, I've tried the following:

• I've also tested this with "env.scene.write_data_to_sim()" . This doesn't do anything for sim components.
• I've also just gotten the stage and written the transform locations per xform but this causes a really bad render issue.

On a side note:
Publishing the transformation trees for these components with respect to the world frame using omnigraph works perfectly fine. This is frankly very confusing because the world to sensor transformation publishing fine but the world to robot base remains a static transformation print out.

[Ltesfaye]

Quick update to this bug: This is caused by the use_fabric mode not writing the robot joint transforms to USD and the fact that omni graph publishes transformations by reading them directly from scene USD. From my testing, working with a couple of robots and turning off use_fabric has no impact on the frame rate of the sensors and also fixes this bug.

It would be nice if there is a way to benefit from use_fabric while also publishing the robot transforms using omni graph (or something more intuitive than omni graph.