27-02-2020, 08:28 PM
(27-02-2020, 10:27 AM)josemendez Wrote: Hi there!
Skin constraints impose two "off-limits" zones for a particle:
- outside the sphere defined by the vertex skinned position and the skin radius value
- inside the sphere defined by the vertex skinned position/normal and the skin backstop radius/skin backstop values.
The first one is pretty intuitive (i'd like to think) as it's basically a "don't move too far away from the skinned position" constraint.
The second one creates a "virtual" spherical collider behind the particle at each vertex (lets call it the "backstop" sphere), so that the vertex can't get too far back inside the character's body. The catch here is that the center of the backstop sphere is placed along the surface normal, at a distance of backstop radius (the sphere's radius) + backstop (the distance from the surface). So if your mesh has pre-modeled wrinkles/folds in it, the backstop spheres will be in weird positions (to the left or the right of the surface, because that's where the cloth normal is pointing), instead of right underneath the cloth surface which is where you want them. Am I making sense?
The solution would be to model your cloth with as few wrinkles as possible (the simulation will add result in wrinkles anyway), making sure that all normals point away from the body as much as you can.
Thanks! This did help a lot with understanding how the backstop and backstop radius parameters work.
Just to clarify, does this mean that the "backstop" sphere is always behind the particle? Is there any way to make a backstop sphere with a center that is some units away from the surface of the mesh, so that the particle can only move inwards, and not outwards?
As far as I can tell, all the normals do point away from the body of the mesh, or at least the blue skin radius visualization lines point away from the mesh in particle editing mode. Unfortunately, because the model is created by a different studio hired by the company we are doing contract work for, I don't think re-modelling the cloth is an option.