CompuServe Thread

Hi Mechadeus, << rot x, y, z.. >> You'll need to convert between your Euler angles to a quaternion. Do you have access to an Inside 3DS R4 book? Check out the script I wrote called Camtrack.k3d. There I had to determine the angle between 2 vectors and then create a valid rotation key for every frame. There's a chunk of code in there that may be of interest to you.. If you have access to 3D Animation by Vince, you'll find some good insights into Euler/quaternion conversion. In addition I found some old posts on the quaternion subject below.. << You mentioned "Quaternions" in a recent thread. What the heck are they? >> If you want to see one, rotate an object in the keyframer a bit in the x, the y and the z and then look at the rotation key in the key info dialog box. You'll find a normalized vector rotated about an axis by an angle. You ponder and say.. but I rotated the object 3 times.. and I would say yes..the three rotations were reduced to a single rotation around this particular axis.. <<How does one compute a quaternion?>> The best advice is to review "3-D Computer Animation" by Vince.. or "Computer Graphics" by Foley, vanDam, Feiner, Hughes.. however, in short given two vectors, you can solve for the angle between the vectors by using the dot product for vectors. Given the angle, now you can solve for the cross product which will give you the normal to the plane that the two vectors pass through. If you used the object's pivot point as the shared point between the two vectors the normal to the face can be viewed as the axis. <<Why quaternions instead of a matrix?>> When trying to get smooth camera movement and trying to get ease to and ease from to work, matrix solutions result in non smooth results while quaternions offer very smooth interpolated results.