Skin weighting not working correctly

#1

I’m looking to solve a problem that has been plaguing me for the last several weeks or so concerning skin weighting. I first learned rigging in Maya and I am now working in Max so this issue is quite unexpected for me and I don’t really know how to go about solving it.

Basically it looks like my scene is seeing the mesh at one location with the skin modifier on and in another location when it is set to off. And this is preventing me from intuitively weighting vertices to either new bones or bones that I remove from the stack and then add back in. When I either add a new bone or remove one and then add it back and then weight to that bone, the vertices appear to get throw out to the location that the scene is seeing the mesh at WITHOUT the skin modifier turned on. I do not know how to reconcile these two positions so that they are the same (I was deducing that if these were both the same location that skin weighting would again act as expected). I’ve done a ton of looking around on the web and have been hearing thins about ‘bind pose matrixes’, the ‘always deform’ option in the skin modifier, and other people who have had similar problems but so far every attempt to fix this rig and scene results in a dead end. I am turning to forums out of desperation and hoping someone who has experienced this before can lend a hand.

I am not sure how to attach a file or I would. So if someone wants to tell me how to do that I will be happy to provide a file.

#2

Here is a link to a youtube video I created that hopefully helps explain the issue in greater detail. If you go to the actual youtube page I have a link to my Area post on this issue and you can download a copy of the file from within that thread. Thanks for taking a look!

//youtu.be/vwnHgdm6IbE

#3

What you can do is toggle the always deform flag in the skin modifier. This is essentially caused because your skin modifier was added when the skeleton wanst in the bind pose.

Toggling the skin modifiers always deform flag is kind of like nuking the history and reattaching the skin in maya (cant remember the exact maya name now)

#4

Matt is right, just go into the skin modifier, tick off the “always deform” option and go back to the bones/ controls from the rig and zero them out, go back to the skin modifier and switch on the “always deform” and you should ready to go. Also before adding any skinning you should reset the xtransform on the objects

#5

Hey thanks!

Yeah I was trying to figure out how to use the ‘Always Deform’ option. Would you mind spelling out for me and breaking down how to go about doing what you suggested? The more specific you can be the better (just because there are too many opportunities for things to go wrong with this much involved).

I attempted trying it myself but am still getting some weird behavior. Basically, I can’t add new bones without it throwing vertices off into some weird location of the scene. It looks as if the position is relational to the position in the video that the mesh goes to when the bones are deleted and then re-added. Essentially it turns 90 degrees and gets shrunk by about 75% and I think I still need to weed this behavior out because it is preventing me from being able to satisfactorily skin weight. I tried freezing transforms on all controls. Not really sure how to go about ‘zeroing out’ the bones because if I freeze transforms or reset xforms they get all distorted and don’t let my rig behave the way it needs to.

So if someone could walk me through this procedure that would be awesome. If you like, you can download the file from my Area post and take a look yourself:
sharkRig_ver21.zip

#6

Hmmm well I think we may have come up with a solution over here. I noticed that if I delete out the keys in the animation where the rig is scaling down I could then weight to existing bones and new bones without the weird results. So we basically made two distinct files. One was a master rig file where we just had the rig at its original scale. Since we needed to scale down the rig for the sake of the scene we created another file that was to contain the animation. Any additional rig changes would need to be made in the rig file. This allowed me to add new rigging and skinning to my rig file, I could then import the new rig components into my animation file and load skin weights from the rig file. Skinning in the animation file still produces the weird result however I can skin in my rig file and transfer those weights into the animation file. So until something else comes up I’m considering this solved. Thanks for the suggestions!

#7

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