View Full Version : mirror weights inconsistency?

05 May 2008, 07:10 PM
hey all,
i've seen this problem a few times but never been able to figure out why it happens or how to avoid it. it's finally bugging me enough to see if anyone else knew what was going on..

sometimes when i mirror weights, the mirror seems to happen inconsistently. it mirrors the majority of the verts fine, but a few random verts here and there will be way off. it's specific to certain models, it seems, and i'm not sure what could be causing it. the latest culprit has a clean history, and is still causing problems. before i've just sucked it up and touched up manually but now i'm annoyed and i want to find out what is going on.

has anyone seen this and come up with a decent workaround?


05 May 2008, 07:16 PM
Did you try different options in mirror weights? Since its smooth skinning I think maya tries to do smoothing on the other side which is independent of your source side. From my experience I would say that mirror weight (in smooth skinning) is not direct copy of weights from one side to the other unless you pick the right options. And also the pose has to be the bind pose in order for it to work perfectly.

05 May 2008, 07:27 PM
this isn't an overall problem like "my weights look different", it's more like a handful of random verts have completely the wrong weighting, even though 95% of them copy over just fine.

even using 1:1 options it still averages the world space of the verts to give an approximation, which would be fine, this is a complete mis-weighting of verts.

it only happens on certain models too, which is why i was curious to know if anyone on here knew a workaround or a way to avoid it. i havne't found any sort of rhyme or reason as to what causes this.

05 May 2008, 07:46 PM
Oh I see. So you mean that there are some random verts which get weighting of joints which they were not spposed get right?

I am not really much experienced but just a guess, could that be related with bind pose issues? (resulting in wrong association between joints and vertices?)

05 May 2008, 09:18 PM
Any influence objects on "hold" ?

05 May 2008, 07:32 PM
Even I am facing similar problem in my new project with mirroring skin weights. Part of the problem I think is that the mesh is high poly and around the lip area two surfaces are crossing each other (that's where mirroring is failing), so I am guessing that that's messing it up.

If anybody would like to look at the file let me know.


05 May 2008, 07:52 PM
and there are no influence objects/joints on the same spot? AFAIK Maya checks for the position of influences and if there are two on the same spot, it`s another reason why it could be messed up.

05 May 2008, 08:03 PM
No influences, Buexe. It's just two joints for the jaw open. And no holds. Let me do one thing I will upload my file. Let me prepare it first to show the problem so you dont have to wonder around looking for it. Thanks.

05 May 2008, 05:40 AM
Make sure you are at frame zero. I just noticed Maya's 'copy wieghts', and mirroring need to be at zero. (or the bind pose of where you set it)

05 May 2008, 06:10 AM
Mirror weights never seems to work for me when I select at the object level. Say for instance if you have a joint right on top of another and try to mirror weights. Sometimes the opposite weight never gets copied.

What worked for me in the past is doing it at the component level. So try selecting all the verts or an area that you want to mirror. You may get more precise results.

05 May 2008, 06:37 AM
Oh wow thanks. That's something I have never tried. Should be more reliable than object level mirroring. Even after this if I cant make it work I will post the file so somebody can have a look.

05 May 2008, 02:04 PM
i always select at the component level (i dont want maya to try to mirror the center verts on a face for example) but i haven't tried regional selection..

my only workaround for now is to duplicate the troubled mesh / copy weights, then mirror on that mesh. it usually works, i just don't understand what is causing the first mesh to get screwy in the first place.

05 May 2008, 01:36 AM
Soulcialism, I agree with you there is a huge inconsitency with mirroring. I am working with the realistic model for the first time and I am facing craziest results. If anybody is interested in checking the problem in the rig let me know, I can send it in an email. I am not sure about posting the file directly onto the forum since the model itself is not my work. Thanks.

Or if anybody can recommend any script for mirroring skin weight. I could have written it myself, but I dont have much time for this assignment so any help is highly appreciated. Thanks again.

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05 May 2008, 01:36 AM
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