How to spawn heterogenoeus environments

[lopatovsky]

Imagine a usecase similar to franka_cabinet, but we have a usd file for 16 different cabinets.
Now we want to run a training with 2048 environments, where each cabinet would be spawned in (2048/16 = 128) envs.

What is the recommended way to tackle such a usecase?

[Mayankm96]

Please check #186