Cull self-intersecting facets in surftocgsurf

[Jarvellis Rogers]

Sometimes when a mesh is coarse-grained in ffeatools it creates facets that intersect, meaning the mesh cannot be used by FFEA and Tetgen until it is cleaned up in an external tool like MeshLab or Blender. To make things easier for the user, would it be possible to add a feature to surftocgsurf that culls these self-intersecting facets during the creation of the coase-grained surface profile, similar to that of culling floaters and cavities in emmaptosurf?

Would it also be possible to add a feature that culls nearly self-intersecting facets (facets with a small dihedral angle between them, usually under 0.1°)? This causes Tetgen to throw an error, and it is much harder to clean up in external tools like MeshLab as they usually don’t have a feature that readily detects faces based on dihedral angles for the user to delete them, often meaning that the user has to scrap the current mesh and re-coarse-grain it to a higher coarseness level or find some way to smooth the original surface profile (or a combination of both). While Tetgen does have a feature that lets the user lower the dihedral angle tolerance, it doesn’t seem to work well for FFEA and destroys the mesh.