Disabling gravity of specific parts in a single asset

Hi everyone.

I am using IsaacGym Preview4, and developing a learning system of the mobile manipulator.

AFAIK, the mobile base is a moveable body that should be affected by the gravity to exert a motion, while the robot arm should usually be gravity compensated in the learning system.

In the Isaac Gym envs, most Franka arms are initiated with the asset option asset_options.disable_gravity=True and the other moveable agents like Anymal are initiated with
asset_options.disable_gravity=False.

The problem is that my asset is defined in a single URDF (the robot arm base is fixed on top of the mobile base) file that can only be initiated with a single asset instance.
In this case It seems one could not separately set the gravity compensation for the sub rigid bodies of a single asset instance.

I wish there could be solutions for this.
Any advice would be appreciated.

As far as I am aware this is not possible for now, I wish asset composition was a thing like game engines. Would open so many opportunities for procedural generation too!

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