Nobody appear to have the answer to this one, but it's quite important. In short, how to replicate Dark Souls or Bloodborne character collisions. Let's assume a system with an unknown number of rigidbody, each moving around at different unknown velocities driven by gravity, physic or by animation. Some rigidbody cannot push each other, while other can. A character can NEVER push another character. A character never transfer energy/impulsion/velocity to another. However, they still collide with each other. A character can be pushed by other rigidbody like an explosion, a trap, attacks, etc. A character can push other rigidbody like debris or breakables. How to do that? If it's not clear what we want, I'll go record a video in Dark Souls.