Help cloth passthrough

[josemendez]

In the first half of the video, the forceps stretches the skin as desired. However at some point it then passes through suddenly and unexpectedly. The second half of the video shows how it reacts to a different mesh (green large capsule)
Q1: This pass through issue improves with larger colliders on the forceps, but there is an upper limit to how big the collider can be. Is there a way to set when the particles will "tear"? I have tried using surface collisions but that does not help at all.

What's the mass of the forceps rigidbody, relative to the cloth particles? Reducing the mass of the forceps or increasing the mass of the cloth will make it harder to pull it around once it's tense.

Here I'm assuming that the forceps are a rigidbody, and you're moving it using forces or impulses. Otherwise collisions against the cloth will of course fail at some point because the cloth is unable to prevent the forceps from moving once it's too tense: you can pull as much as you want until collision detection simply fails because cloth is unnaturally tense.

In order to have two-way interaction between the forceps and the cloth -or for any two dynamic objects to interact in a physically meaningful way, really- both must be part of the simulation. Note you can't explicitly control the point at which collision detection fails, as it's a function of particle size vs collider size: when the pulling force is too large, larger colliders and/or larger particles will make it harder for colliders to slip between particles.

Q2: There does not seem to be a connection between mobile and attached particles. This causes a gap to form (more obvious in second half). Is there a way for the mobile particles remain connected to the attached particles?
Like this:

Particle connectivity is directly extracted from the mesh, since particles are visually "connected" trough mesh triangles. If there's a gap in the mesh, that's probably because your mesh has this gap too.

Also keep in mind there's no explicit differentiation between "mobile" and "attached" particles in Obi: they're the exact same kind of particles, it's just that the attached ones have their position/velocity modified by the attachment.

let me know if I can be of further help,