LC #42 Pipers Alley

View Full Version : Driving a skeleton using another skeleton (MO CAP solution)

03-20-2004, 04:37 PM
Hey guys,

Anyone got suggestions how to use a skeleton, to drive the motion of another skeleton. I have several rigs already set up with maya, using corrective blend shapes and influence objects for deformation. I was wondering if and how one would be able to use a skeleton, one compatible with Motion Builder, to drive the movement of the skeleton already built and bound in Maya?

Any feedback, suggestions, directions would be very helpful!

03-21-2004, 11:28 PM
check out diva, and the maya plugin (of diva) "dominatrix" by house of moves..

its super sweet... and does exactly what you want..


03-22-2004, 12:01 AM
Doesn't that just work for Maya 4?

I'd love a way to do this in house as well. I know this is often done with autorig scripts, but am not sure exactly how to go about approaching this....

03-22-2004, 12:46 PM
try motek's tutorial... worked for me... here's the link:

if you follow their example you should get the results you're looking for...


03-23-2004, 08:09 PM
diva works for maya 5...

I have written a srript to transfer from the mocap rig to the FK/IK puppet... but this only works because my rigs are created with another script i wrote, so that the right things match....

diva will not care if things dont "match"... apparently...

03-24-2004, 02:14 AM
As I said, Diva only works up to version 4. Unless someone has access to a beta or something?

03-24-2004, 02:25 AM
BTW to correct myself a little, it's not so much that DIVA doesn't work with Maya 5 (As DIVA is the stand alone), but rather that there doesn't seem to be a DOMINATRIX for maya 5....

03-25-2004, 09:06 AM
one cannot do this out of the box, i think most people (???) have a workflow to transfer animation from a mocap skeleton to a rig via constraints. i have a button, that pins my rig to the mocap skeleton (using polevector consraints for the arm twist) , then i bake the motion to the controllers. the mocap skeleton and the rig layout should have similar proportions, but you can group and scale the hole mocap skeleton or parts of it, since the scaling will not be transferred. all this can be scripted, so that you only have to push some buttons, but yes, its rig specific.
if you have 5.0 it has become easier, since there is the "maintain offset" function


03-29-2004, 08:37 AM
Sorry to get off track here but...

Is this the general workflow you use for mocap animation?:

I assume the mocap data is recorded onto a pure FK skeleton that is then setup to move the full control rig. After the controls have the motion baked in, then the animators can go in and tweak as necessary.

I've never used mocap before but I'd be interested to know exactly what is involved in it. Also, how does one take the 3d position of the 'ball thingys' and convert that into rotation animation on Maya joints? Is it done with propietary software or is this a time consuming chore?

Thanks for clearing things up. :D

04-01-2004, 07:47 AM
i think its done like this in a more or less advanced way. i saw it on a presentation of the making of a german tv show three years ago, before that i thought one must use complicated mel code to recalculate local and worddspace stuff, or write an importer, or so...
i was quite jealous about character studion for that reason.
i think one can do this with imported markers (locators that move in world space) as well, but it seems more complicated. You get the rotation from point constrainig the IK handles and polevectors.
To make it efficient, one should use shortcuts for applying the rig to the mocap skeleton and use TRAX to copy animation to the mocap, and from the rig (this way you have to attach the rig only once, if you dont have a button to do it automatically)

04-02-2004, 04:57 PM
Connecting the animation rig to mocap data is not such a big deal, if the retrargeting is already done in diva or motionbuilder (the mocap skeleton and the rig have the same proportions).
I use to work with 3 skeletons: one with the mocap data, the rig and one for the skinning.
For the connection you got make some "connectin nodes" in the rig. duplicate a control, delete all the children, including the shape itself and parent the original control under the new node.
This node can be constrait or connected to the mocap skeleton. Thist technique works with control objects like curves as well as with joints (for a fk spine...).
The idea behind this is to keep the mocap data on on skeleon and have a rig without any keys when you are starting to do the offset animaiton.
For the duplicate, delete and parent stuff I have written a small script, witch is not on the mashine in front of me. If anyone is interested, I could post it tomorrow.


04-04-2004, 06:08 AM
Thanks Goob and Antweiler. You guys really cleared it up for me.

One more favour to ask though. Is there any chance one of you could post some raw mocap data in a maya format so that I could try this out for myself? Unfortunately I don't have access to a mocap studio, but I'd like to be able to give it a try.

04-04-2004, 04:45 PM
hey kiaran,

you might want to take a look at motek's website ( ... they have maya tuts on how to connect mocap with ik skeleton, and when you sign up for free you should be able to get access to those mocap files on their site...

andre ;)

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