A polygonal mesh is received and the edges and vertices of the polygonal mesh are analyzed. A positive (e.g., convex or protruding) feature may be identified where the positive feature is bound by a non-concave edge (e.g., a convex edge or a planar edge). A negative (e.g., concave or receding) feature may also be identified where the negative feature is bound by a non-convex edge (e.g., a concave edge or a planar edge).