How to add physics and surface deformation (dents, scratches) to USD models in Isaac Sim?

Omniverse Isaac Sim
,
1

Is it possible to add physics to any USD/USDC model in Isaac Sim and apply surface deformations (such as scratches, dents, or welding effects) directly on the object?

For instance, is it possible to create a scratch when one object rubs against another?

3

Hi, yes, it’s possible to add physics to any USD/USDC model in Isaac Sim, but real-time surface deformations like scratches, dents, or welding effects from collisions are not directly supported in Isaac Sim.

What IS Possible:

1. **Adding Physics to USD Models**
You can add PhysX rigid body physics to any USD model:

  • Import your USDC/USD file into Isaac Sim
  • Add collision shapes (mesh colliders, primitive shapes)
  • Configure material properties (friction, restitution, density)
  • Set up PhysX APIs for rigid body dynamics

2. **Deformable Body Simulation**
Isaac Sim supports soft body/deformable mesh physics for pre-configured deformable objects:

  • Uses FEM (Finite Element Method) tetrahedral meshes
  • Simulates elastic deformation, bending, and stretching
  • Good for soft materials like rubber, cloth, or biological tissues
  • Requires pre-processing the mesh into tetrahedral elements

3. **Contact Detection**
You can detect when objects collide and get contact information:

  • Contact points, normals, and forces
  • Collision event callbacks
  • Contact sensors for robotics applications

What is NOT Currently Supported:

Permanent surface modifications like scratches, dents, or weld marks from collisions are not built-in features. Isaac Sim’s physics focuses on:

  • Rigid body dynamics
  • Soft body volumetric deformation (reversible)
  • Contact forces and friction

Possible Workarounds:

  1. Manual Mesh Modification: Detect collisions via contact sensors, then programmatically modify the mesh vertices in USD based on collision data (complex custom implementation)
  2. Texture-Based Effects: Apply scratch/damage textures dynamically based on collision locations (visual only, not geometric)
  3. Pre-damaged Assets: Create multiple versions of assets with different damage states and swap them during simulation
  4. External Tools: Use physics simulation tools designed for material damage (like FEA software) and import results back into Isaac Sim

For robotics simulation focused on scratching/surface damage mechanics, you might need to implement custom physics extensions or combine Isaac Sim with specialized material simulation software.

Hope this helps!