Cineversity

Subject: Character Rigging, Mocap, BVH, Constraint

We’ve created a rig which is supposed to be animated by bvh-mocap-data. Therefore, we used the typical workflow, creating a FK-rig, which can be connected to the bvh-mocap-rig by the retarget tag, and connect it with parent-constraints to the IK-master-rig, which directly animates the character.

Works so far, but unfortunately, the IK-Master-rig does not follow the bvh-rig exactly. For example, the hands often are a bit to high, and the angle between the upper and the lower arm is not correct. The retargeting from the bvh-rig to the FK-transmitter-rig works fine, but something is going wrong at the transfer of the animation from the FK-transmitter-rig to the IK-master-rig.
Can somebody give a hint what to do to get an exact transfer? Of course we could use PSR-constrains instead of parent-constrains. But the problem with that is that if you mix up bvh-data shot by two different people, the character starts growing/shrinking etc…

any suggestions will be appreciated!

thanks!

Hi anyMOTION Graphics,

If the rig has the exact same measurements (”...the character starts growing/shrinking etc…”), and the “Order” of the axis rotation are the same, then I would suggest to get in contact with the support.

http://www.maxon.net/support/support-questions.html

All the best

Sassi

P.S.: I’m aware that the library has some material about it, but the I’m not certain if there is a solution for this problem in it.
http://www.cineversity.com/vidplaylist/motion_capture_to_ik_retargeting_rig/motion_capture_to_ik_retargeting_1

Dear Dr. Sassi,

we experimented a lot and now got to the following result: The bvh-to-masterrig-Transmitter-skeleton was only connected to the hand-controllers of the IK-masterrig. So the IK did not interpret the animation correctly. That was why there often was a wrong angle between the upper and the lower arm. We now wanted the masterrig to become a FK-rig if a bvh-data was used on it. By doing so and linking every single controller of legs and arms (including elbows, knees, shoulders and hips) to the transmitter-skeleton, we now got an exact transfer of the animation.

The only problem resulting from that is that the masterrig, especially the feet, now start wiggling and popping around as we animate them by mocap. The transfer of the animation from the bvh-skeleton to the transfer-rig works fine, but something is going wrong at the transfer from the transfer- to the master-rig.

Unfortunately, the file can not be uploaded. Cineversity says the file exceeds the maximum allowed size, even though it is zipped and has about 2MB. Is there maybe a email-adress we can send the file to?

Thanks a lot!

Thanks a lot for all the information, anyMOTION GRAPHICS.

The easiest way would be to send it to the support and have it checked out at MAXON.
http://www.maxon.net/support/support-questions.html
They have lots of experience with rigs, certainly more options than I have here. So, I would think that is the better way for those problems.

Sorry about that zip/size thingy, it happens to me as well, I go then one of cloud services (Amazon, DropBox, etc).

My best wishes

Sassi

We have created several characters, all using the same rig. But as every character has a slightly different mesh (especially male and female characters) the rig has slightly different proportions. The hierarchy is all the same.

What we want to do is to create a pose with one character ans transfer this pose to the other characters. So we create a pose, keyframe the controllers and copy and paste the keys on the other character’s controllers. Mostly that works, but in a few cases the hands and the knees have a very different position than the originals have. The other controllers work fine, so we are wondering why there are these problems especially with the hands and the knees.

Maybe someone can give a hint how to finally do it.

Thanks!

Hi anyMOTION GRAPHICS,

To get all the motion easily transferred, I would use the Motion Clips. This is normally the best way to store any rig based motion and transfer those among different characters.
If the rigs are precisely the same, each joint has the same orientation and sits in the same way in the hierarchy, it should work. The distance among all joints will of course change the positions of the final end position in the joint chain.

If I got it from earlier posts, and you have stick with it, you like to have a forward motion with it, which means each step along the chain will accumulate the final position of the “end joint”

(Another idea was presented from Kai for R10 features. Since then the rig has not to be at the same position as the Skin Object. Which means you can have the joints at the same location and the skin deformed characters somewhere else, this might help to find the differences.)

I assume that you have checked carefully all the joints so they line up with all PSR parameters exactly. Only the distance to each other changes, if I got it correctly.

I would highly suggest to make a “1on1”, as my idea of your set up (missing an example) could take a while,  http://www.cineversity.com/home2#tab3  appointment to go through this, if the support had no answer for you.

I guess you contacted the support already—as suggested in the last thread about this theme. Any news?

This is all I can share, perhaps someone else can chime in and share so insights.

Please try again to share a file here or use drop-box.

All the best

Sassi

P.S.: I have merged the two threads, it is the same question.