Constraint tag for rokoko slipping feet (hands)
-
Hi,
I’ve tried following this tutorial:
https://www.youtube.com/watch?v=IRuKDZweTssto “lock” a hand to the surface of a table but no matter where I position the “constraint null” in the joint hierarchy of the reference mocap the rest of the limbs keep warping away from the “constrained” hand. Is there a really obvious way to solve this that I’m overlooking?
Thank you for any advice you can offer.
 -
Hi chemical-subject,
The image can have only 500 pixels vertically.
To use the Character Definition, one must understand that almost all motion transfers are based only on rotation. This seems to be excluded information in this video.
The key is to transfer the motion size-independently. If the position were included for each Joint, the target character would often "crumble".
The best way is to have the T-Poses as closely orientated as possible so all rotations are transferred with the greatest option to match.
That has been ignored in the video, and the resulting rotations created unwanted motions.There is no one-size-fits-all fix for that, but to constrain something only with a position of one Joint-tip is questionable, as it might stretch the Joint.
.
If you would like to fix something like that while using the origin position of parts of the joints, I would set up an IK solution for the two joints that define the motion, so the stretch is not forced, and the motion stays hopefully in a believable range. Again, there is no one-size-fits-all solution. This is a fix of a symptom, not of a source.I have two files below; one showcases the problem when the T-Pose was ignored to set up properly, and the second file uses an IK setup to have the end of the joining chain meeting the same position without introducing stretched elements.
The Goal, can be a child of the Table, in your example, or just positioned there. (I do not have your file nor the image)
Enjoy your weekend
-
@Dr-Sassi! Hi,
Thanks so much for getting back to me on this, I really appreciate it. I've tried to follow your instructions, though I'm fairly certain I've followed them incorrectly as I don’t understand the rational or function behind each step of the process, particularly the role of the pole vector and where each of the nulls should be positioned in the joint hierarchy if the hand is the bone I am trying to impact.
I’ve tried watching some of your tutorials on IK tags but to no avail. I can’t attach the file itself as it’s too large but I’ve attached an image of the setup.
-
Hi, chemical-subject,
Please consider any images submitted here suitable for a younger audience. Thank you.
Perhaps have a look here; this is not short, but the shortest introduction to get savvy with those tools. Keep in mind that character animation is a complex skill to master, and that requires some knowledge. There is a steep learning curve in the beginning; any step jumped over will work like a black hole, and it will suck all creative energy in the future into it. To master this and get the expression you are after, this is the way to go.
https://www.youtube.com/watch?v=rN_5weIhiMY
I'm sure you will find what you need in the instructions. Enjoy!
As a side note, the typical mistake that I have seen over a few decades by now is that setups are not put into the smallest version to understand the tools. The series above follows this idea of getting too complex too fast.
My tip is to set up a small Joint chain and explore IK and Goal/Pole in a file that you can recreate quickly. Doing this on a full rig is questionable from an instructional point of view.All the best
-
Apologies, I'll be more considerate with images in the future.
Thank you for your guidance on this, I really appreciate it.
-
Thank you very much for understanding, chemical-subject.
If you have set up a simple joint IK scene and encounter problems, please always feel free to ask.
Cheers
