re cylinder and ray in article qc fginnbv darkstar ucsc edu koehler secs ucsc edu writes i would be most thrilled if some kind person could help me with the following given a cylinder in d defined as a line segment between two points and a radius e g sx sy sz to ex ey ez and r what is the easiest and not too expensive way to find if a ray defined as another line through two points cuts through this cylinder and if so where i think the test for touching is rather simple if the closest approach of the two lines is less than r then the ray does penetrate the cylinder nope this won t work for a cylinder you can have a line arbitrarily close to the the cylinder backbone and yet not intersect it the test works for a pillbox though a cylinder with two hemispheres attached at the ends thanks ryan koehler secs ucsc edu arun
