The Application of Winding Numbers to the Interior Problem of Nonconvex Polygons and Polyhedra

The winding number for closed curves and polygons in the Euclidean plane is generalized to polyhedra in three-space. The winding number allows us to decide whether a point is in the interior or exterior of a closed polygon/polyhedron. Polygons and polyhedra need not be convex and self-intersections are allowed.