And to follow the splinophilia tutorial all you have to do is to just adjust the QuatX,Y, and Z curves and just not mess with the QuatW curve
Have you tried this? Can you demonstrate it in screenshots? I ask because I don’t believe it to be the case and would love to be shown otherwise.
As far as I can discover, quaternion X, Y, Z values are actually derived as a Cosine calculation based on angle and space location or some such thing so the key values are not intuitive unless you can instantly call log and cosine values up from memory. Plus, the QuatW value plays an important role in the actual bone position.
Simply drag some control points around on a Quat Z curve, for example, and see if it bears any resemblance to doing the same thing with a RotZ curve on a mesh object. I tried this (before reading this thread) and found that a key value of 1.0 might set a bone at 90 degrees but 2.0 was barely more and a value somewhere around 500 got the bone rotated near to 180 degrees. A simple hand-drawn IPO had a bone jumping tens of degrees from one frame to the next despite moving smoothly on preceding frames following the same IPO.
Just looking at a set of bone IPOs shows that the W curve is intrinsically involved in the animation since it is anything but flat. Now, since I still scratch my head over quats, maybe there’s something that I’m missing but if it was as easy as just ignoring the W curve, I wonder why every page that discusses quats starts out by saying they are almost inexplicable to mere mortals :spin:
So, while I agree that you can mess with the curves to alter results (eg steeper curve = faster action) I don’t think it’s as straight forward or intuitive as Eulers in which the value you see on the curve relates exactly to the resultant movement on screen. With Eulers, if you want to rotate something 40 degrees around the Z axis, you can whack a key on the 40 degree point on the RotZ IPO. You can’t do that with Quats and I don’t think you can generally do it without using the W curve.
You can see the Euler Rot values in the transform panel and these values don’t relate much to what you see in the Quaternion IPO curves.
Now, I’m not suggesting we be given Eulers since I don’t know that the known problems associated with them would make our lives better (and quats do seem to be gaining popularity) - or that quat curves are impossible to work with as they are - but what would be great is if someone who actually understands the quat curves could put a wiki page together showing examples of practical, hands-on use of them.
Thanks for your in depth responses, and sorry for wasting your time.
It’s not a waste of time to discuss something which also causes discussion and controversy in other animation forums too. No need to apologise. Plus, as a result of these questions and my follow-up “research” into quats and gimbals, I made myself a little 3-ring gimbal-gyro animation. Fun!