IK Legs squish/collapse onto themselves.

[Domiek]

Hello, I’m having issues on some characters with the latest stable release of Diffeo 1.6. When using IK, the legs don’t bend properly as they did in previous versions. Instead they stretch/collapse into a mush even with stretching turned off.

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This is a character I imported using stable 1.6.

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Here is the same character that was imported on an older experimental version of 1.6.

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I’ve tried to replicate the issue with Victoria 8.1 HD and she functioned perfectly fine regardless if I made all bones poseable or optimized for IK. I tested this with another 8.1 character and she had no issues either.

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So far, the two characters facing this issue are Rocco 8.1 male and Fred 8.1 male. Any ideas how I can solve this?

(Side Note: Holy crap the improvements in stable 1.6 are insane. I especially appreciate how fast morphs load now, went from about 30 mins to 3 per character.)

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[Alessandro Padovani]

This is a known issue for rigify. That is, some daz rest poses, such as G8M, are not compatible with rigify that needs prebended limbs for ik to work fine. One workaround is to edit the rest pose yourself before rigifying.

See #498 for a detailed discussion.

[Domiek]

Thank you for linking that discussion, there’s a lot of great info I’ll try out.

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Out of curiosity, has there been recent changes to Rigify or Diffeo that’s caused this bug? I first imported those two G8M figures a few months ago and did not experience the bug.

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[Domiek]

After taking a look at the #490 discussion, I’ve still not fully realized a solution.

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The following was tested on Fred 8.1

1. The Fix Limits solution is unachievable for me. I may have done something incorrectly but my rigify MCH-shin bone is set to -180,180 by default. Changing this to 0,160 resulted in the same collapsed/squish as before.

2. Optimize IK + Connect IK Chain Legs only Tail-end

   3. Optimize IK + Connect IK Chain Legs only Center

   4. Connect IK Chain Legs only Center (This one looked okay from sideview but from other angles the deformations are extreme)

   

I’ve also attempted manually adjusting the shin bone by a cm but there are still awkward deformations and artifacts resulting in the need for Smooth Corrective modifier.

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Is there a consensus on a proper solution for this or is #490 the current discussion so far? Thanks once again.

[Alessandro Padovani]

Deformations and ik are two different issues.

To get the ik working fine, and avoid unwanted squash effects, you need to edit the rest pose so that the legs are prebended as required by rigify. This shouldn’t affect deformations much, apart the pivot point is slightly changed. You can also do this yourself in edit mode as you like it best.

As for those odd deformations you get at the knee joints, could be some missing jcms or custom HD jcms used by the specific figure. Then HD jcms can’t be loaded with diffeo, since in blender the multiresolution modifier doesn’t support HD shapekeys. But they should work with the HD addon by Xin, if you use the true HD option, that will give you a HD mesh (not subdivided) to work with.

Then as an alternative you may also try the simple ik and mhx rigs. To check how they behave, and if this is an issue specific to rigify.

[Domiek]

To get the ik working fine, and avoid unwanted squash effects, you need to edit the rest pose so that the legs are prebended as required by rigify. This shouldn’t affect deformations much, apart the pivot point is slightly changed.

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I think this is exactly the deformation we’re seeing here, exaggerated by this particular model being on the bigger side. I want to highlight again that these same issues were not present in earlier versions. This is a Daz Original character which means there are no custom JCMs specific to the character, correct?

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These are the results from using a file from earlier this year of the same character, only using “Optimize for IK”.

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[Alessandro Padovani]

Ok I checked it. Fred is using custom jcms. That are not the same as the standard G8M jcms. So, unfortunately, you have to import them as custom morphs. Once you import the custom jcms the deformations will work fine.

To check what morphs are used by the current figure you can use the “currently used“ selection in daz studio.

Then I agree it would be much easier if the “import jcms“ tool would also list the custom jcms for the currently selected figure, instead of having to load them as custom. But this is for @Thomas to decide. May be it is difficult to implement for some reason.

I have no idea about the previous version that you state is working fine. Sounds odd to me. If you can be more specific may be it can help Thomas to find a bug. Anyway the latest development version 1.6.1.0628 works fine here if you load the custom jcms as explained above.

Of course the same applies for any other figure using custom jcms that I guess it’s most of them.

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[Domiek]

Thank you for helping out with this Alessandro. Haven’t really used Daz in so long that I forgot about the hidden parameters to check for custom jcms.

I don’t know from what version of Diffeo the older file is where Fred 8.1 was working fine, it was from sometime in spring. Although I guess that doesn’t really matter now since you’ve shown how to tackle the issue.

[Alessandro Padovani]

please mark as resolved, the tracker is being bogged down by resolved issues left open