Hi, it’s quite a sneaky trick I’m using. I did quite a lot of test to figure out how to do it - basically I’m using List controllers to wire the scale back to another controller (in the List controller) which cancels it out while at the same time wiring it to the width and height of the Bones. For the length, I use the X scale to multiply the X position of the Bone’s child; so when the scale is 0.5 the child moves and the parent’s length is halved. I also noticed that not all List controllers are the same, Scale List controllers are multiplicative whereas Position List controllers are additive for point3 values, I used Float List controllers which are additive for float values.
I’ve got the Bone mirroring working and I’m going to add some options to save and load preset rigs, create extra Bones (for things like pouches) and make the Skin modifier be instanced on to every section of a character (if it is made of several pieces) - I’ll upload another video on Vimeo when I get some/all of those things done.
-Harry