Modify mesh with shader and update collision mesh?

Questions & Answers
1

Is it possible to update a collision mesh with when changing a mesh with shaders ?

2

I think not. Shaders make a change to a mesh on the GPU, but they only do so part way through the rendering pipeline. It’s awkward at best to then send data back into Unity’s physics engine. You might be able to do it with compute shaders, which are designed to allow the GPU to execute certain commands and pass data back to the CPU, but not with a normal shader.