I need to twist a mesh, then bend it to a circle and then "un"twist it without opening the circle.
It was easy to twist and bend, but the untwisting is hard, I hope not impossible.
Here is a image illustrating the question, 1 base mesh, 2 twisted, 3 bened to circle, 4 untwisted circle (faked here):
I guess my problem is that the Quaterions are always global. Maybe some Python script is needed to calculate local rotations and express it in global Quaternions wxyz. But My Math is much to bad…
At first I thought you could just rotate the bone on their local axis, but this didn’t work for obvious reasons (it would twist the circle out of shape)
I was trying to solve it the other day using copy loc constraint to replace the parenting between bones but it kept twisting but this gave a problem when going from the linear shape to the cirlce shape. Though that could “probably” be fixed by using more keyframes. Anyway, I tohught you had given up or found a solution yourself, but as I see this is not the case, I’ll retry my hand at it tonight and upload the file, even if it’s just a partial solution.
maybe a texture trick can do? you’d need an animated texture sequence that simulates the twist, so you don’t have to bother with tricky bone quaternions…
Just one more thing. Unless you want to manually correct each bone IPO for overshooting, you should switch their interpolation mode to Linear by selecting all the channel in the action window and hitting Tkey.
