r23 Character solver
Posted: 22 September 2020 02:24 PM   [ Ignore ]  
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I am working with an older animated character rig that has some extra pieces in the rig that are causing some issues with the character solver and new motion capture library. I have gone through the old rig and renamed all the joints so that I now have 68 of 93 items recognized when I extract the skeleton, but there still seems to be some outliers that are messing up the transfer of the motion capture onto the skeleton.  Looks like it is in the arms. The leftover objects that I can see in the rig are “twists” in the middle of a joint. I can’t delete them as that messes with the weighting of the object on the rig.

Any ideas on how to fix the old rig to eliminate the problems?

https://www.dropbox.com/s/d0rv4q4bqb3u5p7/New_Rig_Movie.mov?dl=0

Thanks in Advance!

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Posted: 22 September 2020 03:15 PM   [ Ignore ]   [ # 1 ]  
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Hi Mark,

I checked your screen capture, but it is hard to say without files.

Any chance you can send me the file via DropBox to my PM?

I will have a look at it this evening.

Cheers

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Dr. Sassi V. Sassmannshausen Ph.D.
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Posted: 22 September 2020 03:42 PM   [ Ignore ]   [ # 2 ]  
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Here is the link to the file without the textures -

https://www.dropbox.com/s/37at0124qomy4xd/NEW RIG PEOPLE.c4d?dl=0

Thanks for taking a look.

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Posted: 22 September 2020 06:58 PM   [ Ignore ]   [ # 3 ]  
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Thanks for the file, Mark, very much appreciated.

I have taken the two rigs into a new file.

The rigs had no T-Pose, so I adjusted it a little bit, e.g., the forearm down, leg closer, etc.

The retargeting use the delta of the given two rigs. Hence the ideal is a T-Pose. I was not certain if you had set both Hierarchies.
Set Reference Pose.
https://help.maxon.net/r23/en-us/Default.htm#html/TCHARACTERDEF-CD_BODYPART_GROUP.html#REF

Even with the slight difference in the reference pose, I was not able to reproduce the problem. I have seen the Arm problem discussed before.

The half leg joints are child objects to the legs. So they follow along and no harm done to the weight. I asked for the file, as the screen capture is not clear if it is an additional or an extra joint. I had problems with different amounts of Spline joints in the past using this retargeting, but, for that I have no solution, as the chain can’t be easily replaced with just an reduced amount of joins.

I hope that answer the questions for the half joint.

The set up tests are recorded here, even with no T-Pose. If you do not like to keep the c4d file in public, let me know, I will stop the sharing instantly, of course

My best wishes

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CV2_R23_drs_20_CAmr_01.jpg
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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

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Posted: 23 September 2020 07:37 AM   [ Ignore ]   [ # 4 ]  
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Thanks so much. It sounds like I missed the creation of the reference T-pose so I will work on that today now that I know it isn’t the extra joint elements.

Best regards,

Mark

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Posted: 23 September 2020 09:37 AM   [ Ignore ]   [ # 5 ]  
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Hi Mark,

You’re very welcome, thanks for taking the time.

The key idea is T-Pose. Any differences that you have with two characters in mismatching poses will lead to problems (or creative expressions.)

Yes, both need to know which pose to use.

I have created a little screen capture to illustrate the Reference Pose importance.
https://www.amazon.com/clouddrive/share/WgIZRlAYyPFOJpgCdMb8yq025HjMyooHw9l3hBLGz1V
Importance if you really like the closest match. Perhaps the character should be different, like turning a well-animated rig into a Zombie character. Which is, of course, an artist’s decision.

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
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Posted: 24 September 2020 04:14 PM   [ Ignore ]   [ # 6 ]  
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Thanks so much, this is very helpful. Things got a lot better with the T pose and I have been able to get a character solver set up in about 15 minutes now that I know which keywords I need to update in my skeleton and using the puppet character as a T pose reference. I can now apply all of the motion capture elements, but have a question about a couple items. 

1. When using the sit down pose, the puppet character hands sit on its thighs, but on my characters the hands often disappear into the thighs (actually, the feet lift off the ground so the thigh/knee/ball/toes are not following the animation cleanly). In some models this is more apparent than others so I wonder if it has to do with the scale between some key joints?

2. I also noticed in the walk sequence that the toes don’t bend as much as the motion capture and so the model’s toes go below the ground plane.

A lot of this rigging is new to me, but I want to explore it. Is there something about the T pose or the length of the bones or position of joints to each other that would cause this problem? See attached movie for samples.

Latest model is here for reference: https://www.dropbox.com/s/37at0124qomy4xd/SOLVED_RIG_PEOPLE.c4d?dl=0

Sample movie: https://www.dropbox.com/s/0oxaf4j987gpj0y/solver.mp4?dl=0

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Posted: 24 September 2020 06:13 PM   [ Ignore ]   [ # 7 ]  
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Hi Mark,

Thanks again for the file.

I guess I tell you now all that you are already aware of. So bear with me.

Character joint animation is based (except for toon-like stretched arms or legs, etc. Animation of PS will change the target!) on rotation only.  Even keyframes on Position should be avoided to prevent trouble. One can’t really rotate a joint above another that has position keyframes, and expect that position animation is kept The parent will be the child’s “world” axis!). The motion retargeting takes the rotation and transfers it to the next.
Not positions! Otherwise, your newly animated character would grow and/or shrink.

Some explorations (Source Rotation, Rot+Pos, Rot+Scale)
https://www.amazon.com/clouddrive/share/M3rV1P8CelNiWbqM8pzfSeE76oZozEFnTu8qPqyC1iQ

In the is way, if one character has longer arms than the source, but perhaps not equally longer spline joints, the rotation will end up with penetration, or distance where no distance was before.

The woman’s foot is set up for high heel shoes, the toes have a different angle than the source based on that. The rigs have each a reference pose. If there is a delta (difference), then that difference will be acknowledged in the transfer, of course. Otherwise, the toes would point in an unwanted direction. Your movie clip shows the foot joint angle-relation very well.

Now you might say that should be all handled by the Character Definition/Motion Solver tags. How would that work, considering the character had a motion on its own, and get from several different sources motion before and after that? Shrinking arms, stretching legs, and adjusting spines each time differently? But that would be required.
How about flat shoes v. high heel shoes? (Rhetorical questions…). Even if it would be possible, perhaps I’m not aware of it, how much of the physical expression might get lost or exaggerated? We use characters to express with body language and actions as much and as precisely as possible. As the first lecture in filmmaking goes: Show – don’t tell. Which sets us some limitations to allow automated processes to take over. Perhaps Ai will do more in the future.

Again, I believe I have told you nothing new, only put into the Character Definition and the Motion Solver context.

If you think there is a problem, please always feel free to get input from the support.

However, I’m happy to look into anything that comes up.

My best wishes

edited

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

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Posted: 25 September 2020 09:01 AM   [ Ignore ]   [ # 8 ]  
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Dr. Sassi:

That’s just what I needed to know. I wanted to make sure it wasn’t something I was doing wrong with the tags/extracting the skeleton.  I thought the same thing about the position of the heels in the remapped model.

My thought is to be able to transfer mo-cap data between a lot of these models so we can have more diversity of movements on different characters in our animations. I think it will be possible, but I’ll have to adjust some of the character’s skeletons so that they all have a relatively similar scale between joints. And with that in mind, I may have to find characters with flat shoes to make that work more easily.

Thanks again for all the insights.

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Posted: 25 September 2020 09:11 AM   [ Ignore ]   [ # 9 ]  
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You’re very welcome, Mark, thanks for the reply.

If you get some ideas during your work on that, please feel free to make suggestions to MAXON.
https://support.maxon.net/index.php

If it creates an easy workflow to adapt very different rig to be useable (thinking of creating a library), that would be great.

All the best

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Dr. Sassi V. Sassmannshausen Ph.D.
Cinema 4D Mentor since 2004

Photography For C4D Artists: 200 Free Tutorials. Texture, Panorama, HDRI, Camera Projection, etc.
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