Hi there,

is it even possible to rig a (biped) character so that it has some squash and stretch features to its limbs?

Thanks in advance, cheers,

- loocas

Yes it is possible to rig so it has squash and stretch.  It takes a little more work to tie it back in to the character control rig with character extensions but it helps.  If you look at relations constraints and scaling the FK limbs you can get started on setting up the nodes just like you would in max or maya for checking stretch distance and scale or translate.

Brad Clark
Co-Founder: Rigging Dojo-Teaching the art and science of character rigging
Author: Inspired 3D Advanced Rigging
The Character Animator Toolkit for Motionbuilder :available now:

Thanks for the tip! I’ll look into this.

Would you have, by any chance, any tutorials or articles on this matter? I haven’t rigged anything beyond some char. extensions on pretty standard MB char. rigs in MotionBuilder yet, so I need to get started somewhere. In 3ds Max, that’d be a totally different story :D but I’m constrained to rig this in MB.

Brad Clark 16 January 2009 04:00 AM

Yes it is possible to rig so it has squash and stretch.  It takes a little more work to tie it back in to the character control rig with character extensions but it helps.  If you look at relations constraints and scaling the FK limbs you can get started on setting up the nodes just like you would in max or maya for checking stretch distance and scale or translate.

any success with that?

I just quickly tried to put a scale on the joints (or the FK-rig parts) of the rigged character and neither in MB nor Maya with HIK it let’s me do it (DOFs are turned off) - looks like as soon as characterization is applied it locks the scaling on bones and also the FK-rig. I didn’t try connecting constraints to these channels.

I could deform the bones using the ScaleDOF in MB, but these values are not open (active, keyable) for connecting a constraint.

“Neill3d” was able to do it, but I’ve no clue how he did it: http://www.youtube.com/watch?v=g68gV6xHGo4

Leander Schock, Lead Animator at Eidos Montreal
work: http://www.eidosmontreal.com
private homepage: http://www.inlume.com

ok, just was able to do it, should have tried a bit longer, before posting :)

in MB ->
1.) turn FK rig visible (in the CharControls Window > Show> FK
2.) add a Relation Constraint to the scene and double click it in the navigator
3.) use the FK rig limb (e.g. <CharName>_Ctrl:LeftArm) and alt-drag it into the Constraint Settings window, make it a Receiver (not sender)
4.)connect your input to the scale (you can test by RMB>setValue) - this value should later probably be driven by the distance of a wrist helper object (or a custom attribute).

....still need to test if this works in Maya with the HIK rig as well

Leander Schock, Lead Animator at Eidos Montreal
work: http://www.eidosmontreal.com
private homepage: http://www.inlume.com

With a stretchy limb I have a problem with a local scale axes orientation. I have attach two images, one with local translation, one with a local scale. So to make good stretch along limb there might be some axes calculation in relation constraint to find a scale orientation like in local translation.

freelance mocap studio AnimArt - http://mocap.com.ua/en/

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