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Correcting for bone length when doing animation remapping

Started by December 16, 2020 06:15 AM
22 comments, last by taylor7 4 years ago

hmmm … ok i think u will need to review the whole thing (most probably) from the start;

retargeting is essentially :

original (source) data/character/motion → Retarget Filter (RF) → new (target) output/data/character/motion

we tried methods which we hoped were going to quickly fix your problem, clearly not; that means u have a bigger issue;

you need to rethink what your RF must do and under what circumstances:

  • what ratio you have
  • how to apply the ratio (positions and/or rotations)
  • which bones need to be affected and which not
  • which time frame to apply these on
  • very often in RFs, end-effectors may also be introduced
  • inverse kinematics can be used to resolve some constraints
  • dynamic hints can be introduced
  • maybe your matrices need matrix Jacobian interventions, etc…
  • and more…

u could look for papers (some are paid, others are free) which have resolved similar issues such as this one ( http://graphics.snu.ac.kr/publications.php​ look for the word “Retarget” ) and see how u can make yours work or behave in the same fashion as in a paper…

About the source data:

  • review your source data thoroughly and find any info u could have missed about it
  • or you may want to try different source data such as the likes of http://mocap.cs.cmu.edu/​ or mixamo
  • or work on a smaller skeleton that has the same problem (easier to debug)

this will give you confidence that your RF is behaving as expected;

anyway, i hope u can make progress, maybe take a short break from it and come back refreshed to retackle it;

until then ?

I think you are right. We have tried all the simple solutions and they do not work to well when the skeletons has different proportions. I also fear that my math knowledge might be a bit lacking when it comes to this.

One piece of information that is not currently being used which might be of interest is that all the skeletons have a bind bose (A-pose), but I also have access to the skeletons in a T pose.

I found this paper which looks very promising: https://www.researchgate.net/publication/220183656_A_physically-bAsed_motion_retargeting_filter/link/5704453c08ae74a08e24625a/download

Thanks

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Hi!

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