CGAL::side_of_oriented_sphere

Oriented_side	side_of_oriented_sphere ( Point_3<R> p, Point_3<R> q, Point_3<R> r, Point_3<R> s, Point_3<R> test)
		returns the relative position of point test to the oriented sphere defined by $$p, $$q, $$r and $$s. The order of the points $$p, $$q, $$r, and $$s is important, since it determines the orientation of the implicitly constructed sphere. If the points $$p, $$q, $$r and $$s are positive oriented, positive side is the bounded interior of the sphere. Precondition: p, q, r and s are not coplanar.

See Also

CGAL::side_of_bounded_sphere