[Question] Soft Robot Simulation

[Emanuele-n]

Hi,

Are there ways to actuate a deformable object, or they can be only passive?
For example, can I regulate the pressure of a fluid inside a soft object to control its deformation?

Thanks

[glvov-bdai]

Hi,

To the best of my knowledge, all deformable objects are passive. I've requested that NVIDIA add support for attaching deformable objects to rigid articulations, which might be able to control deformation in a future release by applying variable pressure, but I think this is still in development or backlog of the PhysX team.

[Emanuele-n]

Thank you!
is it possible to contribute to it?

[StrainFlow]

You can attach rigid bodies to deformable bodies in Omniverse, here's the documentation page that includes that:

https://docs.omniverse.nvidia.com/extensions/latest/ext_physics/deformable-bodies.html

I have seen people create a rigid joint and then attach a deformable body to the rigid bodies on both sides of the joint, and then use that joint to make the deformable body move, but I'm not sure if this would work in Isaac Lab. I'm pinging some people about that now to see if it's possible.

[StrainFlow]

I've heard back, anything that works in USD and OV should work in Isaac Lab, so you can either model this soft body simulation in high fidelity using WARP or you could approximate the joint by attaching a deformable body to a rigid articulation. Here's a nice tutorial on how to spawn deformable bodies in Isaac Lab:

https://isaac-sim.github.io/IsaacLab/main/source/tutorials/01_assets/run_deformable_object.html

[glvov-bdai]

@StrainFlow I don't think that attaching a deformable object to a rigid articulation would currently work in Isaac lab; have you tried this? If so, can you please provide the snippet (I am interested in this functionality).

In my experience, USD <-> Isaac Lab support is not 1:1.

From

source/extensions/omni.isaac.lab/assets/articulations/articulation.py

An articulation is comprised of multiple rigid bodies or links. For a rigid body, there are two frames
    of reference that are used:

Articulations seem to use the physx.ArticulationView, but I think the current articulation implementation does not support deformable objects.

[StrainFlow]

That's entirely possible, I've seen it done with USD joints in Omniverse but haven't seen it done with an articulation.

[StrainFlow]

I'll try to put together a sample to confirm or deny this

[garylvov]

Thank you!