Cineversity

HI there,
I got a question about the retarget tag. As far as I understood I can use this tag
to apply motion from a skeleton (in my case motioncapture data) to another skeleton with the same
naming/ hierarchy but different dimensions/ proportions.

Every time I add target and source in the retarget tag it messes up my mesh completely,
even if I disable “use hierarchy instead of names” as seen in:
“Siggraph 2017 Rewind - Aude Guivarc’h: Hand Animation with Mocap in C4D”// 14min 20sec

Checking the joint hierarchies the retargeting itself works but the mesh my target hierarchy is bound to
is freaking out. Whats the reason?

Please enlight a blind artist. I hope I miss sth. obvious/easy to solve
Thanks in advance.

Mark

UPDATE:

it seems the hierarchies coming from mixamo have most joints aligned along the y-axis or some just zeroed out (Head, Neck, Roots of fingers)
while c4d joints are aligned along their z-axis, which I did by using the align command after adjusting.
https://forums.adobe.com/thread/2392826

I guess this the main problem. Is there a smart/ fast way to adjust the joints alignment of my target Hierarchy to
the alignment coming from Mixamo? Or do I have to go through every joint?

(Tried to attach a .zip and .c4d file but got error message: “invalid mime type”)

Thanks in advance!
Mark

Hi Mark,

I think everyone should write to Mixamo, to have an option to get the axis system they are used to. To avoid this step at all.

The Retargeting tool usually works without the need to align the axis, it is an axis tool only after all. Is it perhaps more a problem of the Skin Deformer? Resetting/Set Binding Pose?
One minute screen capture
https://www.amazon.com/clouddrive/share/Glqpa4qmDN3VCbFfA724gHPwwx2vxkv7MUDdR7hrusc
Manual
https://help.maxon.net/us/#TCAWEIGHT-ID_TAGPROPERTIES

This is a far shot, and I really don’t see the need here, anyway: If the above mentioned is not the problem, one can set the alignment with the Joint Alignment Tool.
Kai discusses here the Joint Align Tool
https://www.cineversity.com/vidplaytut/character_rigging_in_r12_aligning_joints
Please note that the 7 key needs to be used instead of the CMD/CNTRL key to rotate the initial axis. The L key works as well to have a toggle option, instead of holding it.

This shouldn’t be done on an animated rig.
I suggest using the Animation System to store the Mixamo Clips

Does any of this help/work?

I can set up an upload link, just let me know, sorry about the mime problem. C4D will not work, zip should, but the system is randomly picky.

All the best

edited

Hi Sassi,
thanks for your answer, the reason for targeting an adjusted rig to the mixamo mocap is the accuracy needed in joint placement
(shoulder, knee etc- the joints that are just guessed by mixamo rigging process). Of course I use the motion system to store and blend animations later.
As far as I see you’re right- the mesh/binding seems to cause the problem.

the bound mesh is freaking out as soon as I use retarget tag and set source.
I also tried aligning all joints to fit the mixamo alignment (along y-axis) by using the joint align tool.
Even if I delete my skin/binding and bind the new aligned joint hierarchy it freaks out.

Could you prepare an upload possibility? I would like to upload the mixamo T-Pose,  my adjusted (target) T-Pose and animated (source) hierarchy
and the mesh which seems to be the problem, because I think or better say hope I’m overlooking something obvious here.

Thanks in advance!
Mark

Upload was done and received, Mark.

I’m back on the weekend.
https://www.cineversity.com/forums/viewthread/1300/

All the best

Hi Mark,

I haven’t forgotten to look into it, but giving a nearly week-long hands-on class required my full attention. I certainly learned a lot again during that week, so it was a personal update to be better for the forum. No one knows everything. I continuously learn, even using C4D in my third decade. But there is nothing that is really complicated, as with the problem you have here.

Since I try always to find the easiest to explain the solution, it takes a little while. I used an iteration to transfer all the information of the 57 joints. With XPresso that was just a few mouse-clicks.

The target that I had was to get kind of a converter established, that could be used to apply a Motion Clip (GIVE with the Y-axis) and have a rig that uses a Z axis (GET)

I hope any further step is now more what a typical character animation requires.

Scene file/Screenshot
https://www.amazon.com/clouddrive/share/Tp8zMfHtjp2KRoYMCD303F9AlyHQw4nNwT9BMr0vbr4

I have added the screenshot from my “Joint Align Tool” settings, as it might require some other settings for other results. The key is that the Constrain transfers only the rotation, BUT the “Maintain Original” is set. In this way, the rig doesn’t implode when new rotations are given, it is just added.

All the best

Hi Sassi,
thanks for your input, but I’m afraid I dont get it.
Till now I thought the retrageting works as both joint hierarchies themselves animate properly but
once I display the mesh its freaking out, even if I reorient the joints to fit the orientation mixamo provides.
Whats your workaround?

Reorienting the joints but with expresso and constraints? How does it work?
Is your file kind of a reorient-setup? That in the end keeps my binding intact?

Please enlight me
Thanks

Hi Mark,

The retargeting allows to transfers the rotation of the joints, given the same axis alignment of both rigs. You pointed out that the Mixamo approach is a Y-axis along the bone, it is not, it is aligned with the world, and you have set up your scene with a Z-Axis along the bone.

Since you linked to an Adobe thread, this seemed to be a common problem, so the idea is of course to build a converter. This is what I have shared above.

The “Get” rig has its axis in z along the “bones”. I understood that is what you have asked for.

Please know, that the idea of Mixamo’s Y world has a pretty straight forward base. It allows easily to get the T-pose back. Anyway, you like to work differently, I understand that. The best idea is to know what your target rigs are, e.g., for the Motion Clips. Note that the following needs to be done on a non-animated rig.

=======

Let’s start to solve this from a different angle, shall we? Switch off the Skin object. Then select the Joints (Target) you have for that Skin Object, not the new one (Source). Select the top Joint of that rig (Target), and call up the Align Joint tool.
Set up the Tool as in the image below.
Go to the Weight tag. Press the set “Set Bind Pose” button. Now switch on the Skin again. It should show no (!) change visually, except all the joints have a different axis orientation. DONE!
Align Joint Tool for this conversion:
https://www.amazon.com/clouddrive/share/8LxkbiuVLLeTDfeokUU0Em1scDknQWbTSb9irhrimnI

Go ahead an create an Animation Clip for the Source. Apply a new Motion Clip tag to the “Target-rig” (your rig that drives the Skin) The animation clip from the “source” should be in the left list. It is useable now, as you can see in the file that I have sent you via PM.

Is that what you were looking for? A dancing robot Cool.

Cheers.

Thanks Sassi,
without this step by step approach and view on it from my scene/problem I would have never gotten it :D THANKS A LOT
Understanding this I may get what your converter file is for. Do you have a step by step approach for this also?

But what I still see is that the fingers are screwed- not in terms of binding but the alignment.
Did you see that too? Whats going on there?
I already noticed that the mixamo joint axis arent 100% consistent especially at the end of the individual joint hierarchies.

P.S.: its not about the dancing especially, its more as you said having a workaround to apply every kind of mocapmotion to an adjusted joint hierarchy,
because mixomo only asks for a few joint-placements and guesses the rest, in terms of a robot its needed to have them all exactly placed where
the mechanical joints are.

Again: Big T H A N K S for your time! I really appreciate!!!

Mark,
You are very much spot on, the fingers are weird. Since it is a robot, I kind of missed it.

If you check the Mixamo file, e.g., the “mixamo rig:LeftHandThumb2”, you will see that the axis is off. Since it is animated, I think a converter like the one above might work. But from Y to Y axis then.

I have to spend more time on this.

You mean a step by step for the Xpresso and Constrain set up?

Hi Sassi,
for me the skin-off; joint align; setbind; skin-on; retarget-active; is straight forward.
But I guess your expresso/constraint file had a reason that is just
too smart/abstract for me without step by step explanation.
If it even eases dealing with those problems I would be interested,
but as I said the “different angle” solves 90% of my problem already.
Checking the hands problem too at the moment.

Thanks!
Mark

Thanks a lot, Mark, for the kind feedback.

A short step by step:

I copied the Rig one time. The copy got the Constrain Tag.
The scene was set up by applying a single constraint tag to the parent, then “Copy Tag to Children”. Either set it up before or when copied: Maintain Original and the Position checkbox off.

The Xpresso had two link lists in it, one holding the original rig, all 57 joints. The other one, all 57 constraints from the copied rig – at once – so they stay in the same order as the original rig.

The Iteration node counts per frame from 0 to 56 (equals 57), each number represents one object in the Link list. In this way, the field in the Constrain is filled. (You can alternatively ignore XPresso and do it 57 times manually, the same result [hopefully… ])

Then the Xpresso is switched off.

=====

The Y-axis of the source can be aligned before the Animation is “baked”. Set the Joint Align Tool for the “Target” rig so that the axis XYZ will show up in the same way as in the “Source”. The Y axis should point to the next joint, and then have an eye on how the Z and X axis compare. Compare it on several joints. Like the Left index finger, is the Z up or cross the hand, etc.
This is crucial, and if done correctly, the fingers should line up then.  It would be nice to have an old, and a new T pose, one Z on Y oriented, to get this workflow sorted out correctly.

My best wishes for the project.