View Full Version : Joints and keyframeable stretchy

03-17-2009, 10:59 AM
Greetings everyone,

I've done my search through the forum on stretchy IK and I've seen the various plug-ins and the new options with joint bones. I'd like to move on to 9.6 (still using 9.3.1) and get familiar with the joint bones. I've made a rough 3 leg joint chain to play around and I can get the ankle bone to stretch by tying the scale to the IK target. So I can stretch the calf muscle fine. But I have a couple of questions.

1. What would be the proper way to get the knee (thigh muscle really) to stretch/move in relation to how much the calf is stretching?

2. Can you envelope the stretchyness? I'd like to be able to control when the rig goes to a stretchy rig.

I'm trying to re-create something similar to what's in this XSI training material.




03-17-2009, 11:11 AM
u can do it with a layered rig adn some constraints...

setup one limb... make it normal, non stratchy. Clone the limb hierarchy, set it up the same, same controllers, pole, whatever, but make it stretchy IK.

Then, use some form of constraint, same as item, simple position/orient/scale constraint, whatever... to tie limb 1's stratch to limb 2's stretch, multiplied by an intermediate value... such as a slider, master channel, envelope... whatever.

03-17-2009, 06:20 PM
Thanks RH,

I'll consider that technique. Shame that you can't envelope the effect.

I might just brush off XSI and follow the tutorial.