Understanding the Difference Between "Drag" and "Damping" in PBD Material Parameters

Hi everyone,

I’ve been working with PhysX PBD materials in IsaacSim and came across two parameters: Drag and Damping. While I understand that both of these relate to forces that resist movement, I’m a bit confused about how exactly they differ and how each parameter affects the simulation.

Could someone help clarify what these parameters specifically control in a PhysX PBD material? For example:

  1. How does Drag affect the simulation? Is it related to resistance to motion through a medium or something else?
  2. What role does Damping play in the PBD material? Is it linked to internal energy loss or another kind of resistance?
  3. Are there specific scenarios where adjusting one is preferred over the other?

From my observations, when I let cloth objects free fall, Drag results in an overall lower velocity when using the same numerical values as for Damping (see Figure). However, I noticed that Damping also affects the velocity of the entire object, which contradicts my understanding of damping. I thought Damping should primarily result in internal energy losses within the material, without directly impacting the velocity of the entire body in free fall. This has left me wondering about their underlying mechanics and intended usage.

Any insights or examples would be much appreciated! Thanks in advance for your help. 😊

Isaac Sim Version

4.1.0

Operating System

Windows 10

GPU Information

  • Model: TX4090
  • Driver Version: 32.0.15.6109

Please check if Particle Simulation — Omniverse Extensions latest documentation is helpful.

Thank you for the suggestion, but I’ve already reviewed the Particle Simulation — Omniverse Extensions documentation. Unfortunately, it didn’t fully clarify the specific implementation differences between the Drag and Damping parameters