[Feature]: Entity set scale support

[SamratSahoo]

What feature or enhancement are you proposing?

Enable the ability to scale the size of an entity dynamically after a scene has been built.

Motivation

In robot learning, scale randomization is a commonly used technique for domain randomization. During sim2real experiments, I found that the ability to randomly scale entities would significantly enhance robustness of learned policies. Currently, I have to pre-spawn all scaled versions of objects and swap them between episodes, which is inefficient, especially for parallel environments. I believe that scale randomization would be high ROI for Genesis.

Potential Benefit

• Greatly increase the scope of domain randomization possible in Genesis.
• Enable training of more robust policies without compromising training speed.
• Reduce overhead and complexity associated with pre-spawning multiple scaled objects

What is the expected outcome of the implementation work?

• Ability to scale an entity using a floating point factor.
• Be able to set this scale after the scene has been built through some method (i.e., entity.set_scale(0.7))

Additional information

Without dynamic scaling, training either becomes slower (due to pre-spawning + having to reduce number of parallel environments to support memory constraints) or suffers from reduced domain randomization. If this feature is not planned for Genesis, I could attempt to implement it if given a roadmap outlining the required steps for implementation.

[Kashu7100]

I think this is somewhat related to #1589
It would be nice if we can have entity.set_scale(0.7, envs_idx=envs_idx)

[Satvik1701]

This would be super helpful for me too.