[comp.graphics] Lines and Planes

herbst@ecsvax.UUCP (Robert T. Herbst) (04/01/88)

re: Line and plane
Perhaps we should insist on a course in plane and solid analytic
geometry. A plane has a normal. The direction numbers of the 
normal are found as a,b,c where:
		ax+by+cz = d.
is the equation of the plane. The angle between the normal and the line
can be determined. If angle = 90 then the line is in or parallel to the
plane. Otherwise the line may intersect the plane in or outside of
the triangle with veritces A,B,C. Having made the above tests then the
matter of where the line intersects the sides of the triangle can be
determined.
herbst@escvax