# Translation of euler angles into rotation around arbitrary axis

 P: 1 i have an orientation of a 3d object in space given by theeta, si and phi i.e. angles which the objects makes with respect to three axis. Now i want to translate the problem such that i get an arbitrary axis rotation about which to some calculated degrees would produce same orientation. Practical Problem. I'm trying to give a specific orientation to an object in VRML builder 2.0 for which i have information in theeta, si and phi...
 P: 688 I don't know VRML (so I really don't know what theta, phi ans psi mean), but I think you should be able to try the following: Take an arbitrary unit vector --say, the unitary X, (1,0,0)-- and apply the three-angle rotation to it (or one rotation at a time, but, if the angle description is like pitch-roll-yaw in airplanes, the order is critical), in order to get a rotated (and also unitary) vector R. Now, the cross product X x R will give you the axis of the equivalent rotation, and the dot product X . R will give you the cosine of the angle between the two vectors. So rotating this angle around the axis given by R is an equivalent rotation. What I'm not sure is how to determine to which side you have to rotate, clockwise or counterclockwise with respect to the vector R. But I think that hacking a bit around this idea you should get it right.