Is the object guaranteed to be closed? Convex or not.
Yes. Objects are guaranteed to be closed (for now) and must account for both convex and concave geometry. Is their an algorithm which will do this for both with a single equation? Or would it require different equations/logic-branches for each?
Also, I want it to handle weird geometry with verts forming concave shapes which bow in past the objects local origin. Say you take a unit cube a split two opposite faces, along the z axis, into four faces each. then you take the center vertices of those four faces and translate them both -1.5 along the z axis. You'd have one vert which went inwards (forming a concave surface) past its own origin, so I can't rely on a vector from the origin to each vert, that compares with the generated normal to check the total angle between the two or something.