Leon Chen wrote: > I guess it is counter clockwise, am I right? I guess it is too. > Can i change the direct if I want? Yes: instead of writing RotateX(angle), write RotateX(-angle). -- François Bertel, PhD | Kitware Inc. Suite 204 1 (518) 371 3971 x113 | 28 Corporate Drive | Clifton Park NY 12065, USA