Hello Russ, Friday, October 11, 2002, 5:43:29 AM, you wrote: I know about this error. It happens when cylinders' edges touches. There is still a warranty that the contact point is near the place where it should be. It was not an error in my eyes I only wanted to reduce calculations. I'll think how to fix it. -- Best regards, Konstantin mailto:slipch@gsc-game.kiev.ua