View Full Version : Spine IK challenge

06-21-2004, 07:50 AM
I am trying to make a spine that can be controlled from either end without affecting the other.

Examples of how this could be useful..

1.. a character sitting on a swivel chair.

I want to be able to move his lower spine around (swivelling and moving with the chair) whilst keeping his shoulders still so he can rest his elbows on the table. But also have the ability later to keep his lower torso still and make him turn his shoulders and top half..

2 a cat

On a cat, the spine needs to be fluid so you animate move either end without moving the rest of the body on FK..

I have been trying to do this for months now (on and off) and haven't come up with a good solution. (I do have some unstable versions that work but theyre not ideal)
If anyone has managed something similar, I'd like to hear from you.

06-21-2004, 09:52 AM
Maybe combining bones with BezierBend ( check Flay ) would be a solution. Never tried combining it with bones but bezierbend works with weightmaps so in theory it could work.


06-21-2004, 10:36 AM
Base bone should be "stabbing" the back of the character...then child bone chains could be created going in both directions, and they can be setup in the fashion you described from that point.

06-21-2004, 11:10 AM
Thanks for the replies,

Bezierbend looks interesting, I need to play around with it.

Having the base bone half way down the back is something I tried, and it works great for certain moves , but it takes a lot of baby-sitting to get it looking natural as it's in the middle of a curve and has to move around a lot.

I want to make a multi-purpose spine that works effectively like it has no Root. It may well be impossible in Lightwave.

It would be great if you had IK chains with no direction just a solid goal at either end whose position and rotation would control the curve between them.

07-01-2004, 10:14 AM
Well, I've just about got one working now.. Not as good as i'd hoped, but it works.

07-06-2004, 02:04 PM
That looks cool. Hou did you managed to get it? I'm trying to do something similar...