Cineversity

Hello,
I’m adding an eyelid rig to Cinema’s Character Object and the skinned vertices are shifting after I play a blink animation I made. It gets worse with every loop of the Timeline and I have to hit “Reset Bind Pose” on the Weight Tag every time to get the vertices back to their correct positions (Before_and_After.gif, attached).

I am not able to upload my Scene file, so I’m hoping I can describe my setup and hear some tips on what I might consider.

Joints
My eyelid joints are controlled by an IK-Spline tag (SplineIK.jpg, attached). The spline is being Pose-Morphed from the top lid to the bottom lid for the blink.

Tags & Priorities
(Hierarchy_800.jpg, attached) The Pose Morph tags’ Priority in the Hierachy image are set to 60 and the IK-Spline Tags are set to 70. The User Data driving the Pose Morphs is controlled by an Xpresso tag with a Priority set to 90. When I turn off the mesh and just watch the animation with joints, there is no lag which leads me to believe it isn’t an issue of Priority. I’ve tried shuffling the Priority of the tags, but to no avail. My rig is above my geometry and deformers in the Object Manager.

The Mesh
I did have some issues with moving my skinned mesh’s points and having them snap back (even after running ‘Set Bind Pose’ on the Weight tag). Did I break something and, if so, can I restore the mesh once without having to restore the skin weights every time? It’s as if the deformed vertices aren’t being reset on Frame 0 and they get slightly more deformed with every loop.

Any ideas? Thank you!!

Hi Blastframe,

I have sent you an upload link. As usual, please no 3rd party parts in it, and just the parts that will allow me to reproduce the problem.

Without a scene file and the option to explore anything first hand, I don’t see really an opportunity to answer professionally.

I will keep the scene file private, but I will answer, if something is found, here in the forum.

All the best

Thank you for your help, Dr. Sassi. I have uploaded the file. Please let me know if I can provide you with anything more.

Thanks a lot, blastframe!

I will start exploring the setup.

Talk to you soon.

Hi Dr. Sassi,
I sent you a file via DropBox with only the eyes called ShiftingVertices.zip. I turned off all of the Character Object components and reduced the project even more to the rig causing issues.

Skip this post, it doesn’t apply here!

Blastframe,

Please try the following:

Go to each of the four PoseMorph Tags of the Eye Lid (upper, lower; left, right)

• Set each individually to Edit
• Click on each pose and select the Post Deformers option
• Set then each back to Animate.

I have used the Doodle tool to draw over the points, and after a couple of hundred loops, there was no shift anymore.

I guess that makes it clear why I ask for a file. Thanks for understanding.

All the best

Hi Dr. Sassi,
Thank you for looking into the file I sent you. When I take the steps you are suggesting, the eyelids no longer animate up and down. Here is a video of it:
Screencast

Is there something else I must change?

I think the reason this doesn’t work is that the splines aren’t being deformed except by the Pose Morph itself.

I have found the answer to the jitter: the Spline-IK tag. By adding an Up-Vector constraint to the joints, the jitter is gone. (credit to everfresh on C4DCafe).

Thank you, Dr. Sassi, for you help and quick responses! You’re the best!

Thank you very much, blastframe.

About my “procedure” above, after an hour of exploring the setup and watching the vertices, I missed that the blink was gone.

The up-vector solution, great, because I was not finding anything inside the set up that fixed it. I made a list of all priorities and could not find anything that solved it. The whole set-up has over 700 objects (according to the Project information).

I test every single aspect of a file that I get, and sometimes what looks like a fix might cause more problems along the way. Each individual file has so many ideas in it, all good by them self, but sometimes they collide. What made me curious was the fact, that the Skin object could be disabled, and after a minute of looping, the mesh (skin back on) had shifted anyway so I couldn’t be anything based on the mesh, it must have been earlier.
Yes, I centered the Spline IK as a problem, but I assumed more a rounding error or something like that. I even placed keyframes to the Joints and switched off the IK, all was fine. However, did not got the idea to use a constrain on every joint. The Up-vector solution makes so much more sense than my last hunch.

Again, thanks for updating the thread, really appreciated. Thanks as well to everfresh from here!

I tested it, and it works fine here, thanks for the tip. I had tried all options inside the IK, but this works, thank

ENJOY.

Ah, I didn’t want you to go to so much trouble, but I am extraordinarily grateful for it! Thank you and have a great weekend, Dr. Sassi!

Thanks for the reply, blastframe, yes this was my morning+.

Yes, I have to admit, the Spline IK is not often in use here, so I missed out to find all the possible consequences with it.
I will explore it now, this was a little embarrassing.
Anyway, I learned something. Thanks for that.

Have a great weekend as well.

Summary:

Since we don’t have the model available to share it, I wanted to showcase the solution for the problem. Besides, the model had seven hundred somewhat objects and tags according to the Project information C4D had provided.
I would like to demo the problem first, and then the suggested solution.
I follow here the setup of the discussed scene file.
If such detailed control is not needed, I would just go with the PoseMorph working directly on the mesh, set after Deformers (mostly the Skin Object), and avoid vast numbers of joint, constraints and up-vector functions as well the Spline IK. Les parts, less complexity, faster troubleshooting.
However, the rigging should always serve the Character-Animation-Artist.

Scene file and screen-capture
https://www.amazon.com/clouddrive/share/pL8hLjh5PCfRZ3hq2b3AksTh9DVGV3Y9x9OAX5qbfDS

For what it is worth, I followed up on a tip to utilize Spline IK handles. No success.

ENJOY