View Full Version : Twist and shout

Thomas M.
10-23-2004, 04:32 AM
Actually I just want to twist bones, but unfortunately there's a lot of shouting going on here.

The point is: I need to animate a tentacle into a certain position. All tests using IK chains or IKBooster failed so far. The best thing to animate the tentacle precicely is doing it by moving each bone or groups of bones. My only problem is that if the overall look is fine, I need to bank rotate the arm at some places to show more or less suckers. How do I do this without changing the position of the bones? The arm is supposed to point in the same direction, only with a little twist.

Thanks for every comment, because the deadline is coming nearer at great speed and I'm going bersek.


10-24-2004, 10:56 AM

tricky one (to me anyway) what I would do is employ a dual skeleton set up. The main skeleton controls the positions/rotations (except bank) of the tentacle, and is probably what you've got already. The Second skeleton is used to control the bank (or twist) of the tentacles.

I'll try to explain how to set it up but this could be a little tricky to follow.

1) Clone your existing skeleton (not the IK rig etc just the bones).
2) Rename the cloned bones so you can tell them apart.
3) Parent each cloned bone to the equivalent bone in the original rig.
4) Deactivate all of the bones in the original rig.

The idea is that you should now be able to animate the bank using the new bones which will take their position/orientation from the now deactive original skeleton.

This basic version has the problem that bank twisting is not inherited down the tentacle but it should be possible to fix that with expresssions or something if it gets too anoying.

Hope that helps,


Thomas M.
10-24-2004, 02:50 PM
Thanks Julian,

that's indeed a very good idea. I'd love to use spline deformation. That's so convenient, but unfortunately I don't see any way to use it with my octopus and its 8 arms. It's either x,y or z-axis and you can't reduce the influence with weight maps. Especially there's no way to bank rotate the arms with this tool. That's so sad. This tool would have saved me so much time. I'm having a sh...y time to position each arm. That's 8 times 24 bones and each time you move the base bone all the rest isn't in position any more. Hate it.

Larry did have the idea to rotate bones in groups (Thanks Larry, the movement of you tentacle looks really great), which saved me some time. IK just didn't help me in any way. It's strange. You can do so many great things with LW, but then it's so hard to move a tentacle (In a very precise and fast way).

If anybody ever did something like that and knows what trouble I'm going through: Do you have a convenient solution?