Having problems/bugs with human body rig


I used Makehuman to get the model of a basic woman and then started working on improving the model for a project of mine. However, when it comes to the rig I am now facing a weird problem that I have a hard time fixing.

As is usual with Makehuman, the model comes with a full rig, that however leaves much to be desired and will definately need to be improved by me. That wouldnt be much of a problem, but I have found a grave issue in the rig regarding the neck/upper spine area.

The problem is that though some wizardry, the vertex group from the upper spine area ALSO applies to the neck area (but the vertex group for the neck area also still applies to the neck), so basically the neck bone has 2 vertex groups attached to them: the neck vertexes and the upper spine vertexes. Now this is a problem because the spine vertexes have no business beeing attached to the neck bone and it causes the upper body area to strongly distort when moving the neck.

I have tried quite a few things, but I have no explanation for this. The entire rig itself seems to be made with techniques I dont seem to be familiar with (even though Ive done quite abit of rigging), most notably that the vertex groups dont seem to be directly tied to the bones using their names, as in I can change the name of the bones to something completely else and the vertex groups will still be attached. Likewise, this also means I cannot add vertex groups to already existing bones, because it wont accept them even if the name is identical.

It is worth noting that the rig does use shape keys for facial animations.

Heres a link to the model so people more experienced than me are able to take alook at it. The troubled bone in question is “Neck” and the two vertex groups are “DfmNeck” and “DfmSpine3”, the latter of which should not be attached to the neck, but is for some reason.

It goes without saying that you please do not use this for any of your own projects or something:

Anyways, thanks in advance. Help with this would be greatly appreciated!

Gentle push, I could really use some help with this. Thanks in advance.

Although I don’t use makehuman (any more), with other models I have used I usually just use the mesh and then use the Rigify to use as a baseline for refining everything.

Thanks for replying. I do want to refine the rig further, but that really isnt the issue here, but instead fixing a rig breaking bug that prevents me from not only using the rig in any meaningfull way, but also prevents me from refining it further.

Can you do me a favor and take a look at the blend file I included? The entire issue is outlined in the first post and I really dont have a whole lot more ideas left of how to fix it.

If worst comes to worst, I might try to brute force it and just rerig the entire freaking thing, but im not even sure that would work and I would like to avoid it if necessary.

If you select the DfmSpine3 bone, and then go to the bone menu, you will see that the ‘Deform’ is checked (this is true for most of the dfm bones). Set the Curved Bones: Segments to 1 and you will not see any transformation of the spine.

If there are problems with other bones, this may be the problem.

Omg, that fixed it. Thank you so much for helping me out on this! This potentially saved me hours of work!