Let S and N be the south pole and the north pole of the sphere s, respectively. If P1 is a point on s, then the computed point P is the stereographic projection of P1 on s to the tangent plane sp at S, i.e., P is the intersection of the line l, which passes through N and P, and sp. If P1 is a point on the tangent plane sp, then the computed point P is a point on the sphere s such that P1 is the stereographic projection of P on s to the tangent plane sp.

For a detailed description of the object created P, use the routine detail (i.e., detail(P))

The command with(geom3d,StereographicProjection) allows the use of the abbreviated form of this command.