Simulate Sand/Soil/Mud using FleX engine in Isaac Gym

I saw that FleX is able to handle soft body interactions, and is also able to simulate more complex interactions (NVIDIA FleX | NVIDIA Developer)

For now, I am creating a soft body using create_tet_grid and tuned the soft body parameters that kind of mimic sand/soil/mud, but simulation for such terrains isn’t elastic, as in the deformation is permanent. I’m not very sure how to get a more accurate result with permanent deformations.

  1. If it is possible to simulate sand/mud/soil using the FleX engine in Isaac Gym, can someone help me understand how to go about it?
  2. If not, can anyone help me understand what each propeties mean in isaacgym.gymapi.SoftMaterial
    a. What does property activation mean exactly?
    b. What does property activationMax mean represents?
  3. And lastly, how to tune all the soft body parameters such that the deformation in the objects is permanent, so that it almost mimics a soft soil


Hi there,

To try and answer your questions:

  1. Plastic deformation is not currently supported, the FEM model is purely elastic.

  2. The parameters for Young’s modulus and Poisson ratio correspond to elastic stiffness and volume preservation in the standard engineering sense. The activation parameters are for fiber based actuation (e.g.: muscle contraction), but these are currently placeholder and not supported.

  3. I am not sure it will be possible to do permanent deformation using the current material model. Possibly using a high damping value you may be able to achieve something similar (like a viscoelastic material), but this is only an approximation and may introduce other artifacts.

I think future version of Gym will improve support for plastic deformation.


That gives a lot of insight. Thanks a lot, Miles for the answer