whynotme

Thanks, but I still don't fully understand I am not good at maths, especially at 3D transform. I am working with Flash, it is a 3D environment but has only 3 rotation tools: around fixed x, y, and z axes. Now I have a cube at a random position and inclined at random angle. And I want to rotate the cube around its edge, but I only have rotation around global x, y, z axes, how can I rotate the cube around its edge - a random axis? And there is another problem, I don't know why and how to solve: When I apply the rotation, ie rotationX(30) then rotationY(50), rotationZ(70) - the angle is just for example. Then I reverse the rotation, rotationX(-30), rotationY(-50), rotationZ(-70), the angles are exactly like the previous step, just negative, but the cube didn't come back to the beginning, it stopped at a random position. What is this problem and how to solve it? Regards.

Hi, I want to covert between global and local coordinates when rotating 3D object because some program only allow to rotate by global or local coordinate. Example in this image, if I rotate Y by global coordinate (black coordinate) then the red object will rotate around black y axis. But I want to rotate it around y' axis, the local axis of the object. How can I rotate object around local axis using global rotation? And how can I rotate around global axis using local axis? Thanks