Character Rig Has Issues with automatic weights

This is my first question here, and I usually am able to find help via YouTube videos. But, this is something I could not find any help on, so I came here.

I am not new to Blender, and have used it to do simple models such as houses, plains, stationary objects, just simple stuff like that. I didn’t think I could do a character model, but I saw a video that showed me a method I had never known of before. Basically you start out with a UV Sphere and you subdivide it several times, then you go into Sculpt Mode and start grabbing it and morphing it till you get the look you’re wanting.

Well, I was successful on the 2nd try of making my model, and proceeded to make another. The 2nd model I decided to rig first. So, I created armatures, then I parented the mesh to the armature, but this is where I ran into a problem. It would do 1 side almost perfectly, but the other side would be all discombobulated with vertices sticking out randomly, and such.

I went to weight paint mode to erase this stuff, then to add appropriate weights. But it would do the same thing when I painted it. It would cause all sorts of junk to appear and I couldn’t figure out why. I’ve tried all sorts of stuff. And none of it has worked. I tried cutting my model in half, and then mirroring it, then connect it again. (By connect, I mean I brought the 2 halves close together.)

My guess is that because it is sphere based, it is causing all of this wacky stuff. The video I saw (I only saw the beginning part of it) was this:

Remember, on one side it works just fine, but on the other, it does all kinds of weird wacky stuff.

This is also preventing me from working on a project that I can’t continue till I get some help with this. Any help is much appreciated!

Basing it on a sphere doesn’t mean anything.

If you have asymmetrical deformation, even after deleting half and mirroring, then there’s something wrong with bone/vertex names or position. Delete half the armature, select all, autoname L/R, symmetrize, reweigh.

Also, rather than applying your mirror, keep it live, above/before the armature modifier. Use “merge” option to manage the join at the center line. Scale your midline verts *0 to a cursor at the origin to make sure they get merged. (Or assign a vert group and shrinkwrap to a big YZ plane at the origin to do it non-destructively.)

That might not be the only problem… From sphere->character means you were using dynotopo, and dynotopo sculpts can end up with a lot of verts. High vert density can break autoweights.

Thanks! I’ll definitely try this out. I posted this same post on another blender Q&A board, and nobody answered. Thanks!

Wait, do names have an affect on things? Because when I mirrored, it did “Left Arm.001” and so fourth. Could that be the problem? I haven’t tried your fixes yet, but I will in a little bit.

Yes. Blender knows to mirror weights because of the names of the bones/vertex groups. It uses “.L” and “.R” to know to mirror. Look at what happens when you autoname/symmetrize your armature like I said. Those are the naming conventions you want to use.

That may be the answer to the problem! Thanks a bunch! I’ll try it out once I finish another blender animation I am working on. :wink:

Thank you so much! I wasn’t aware I needed to put right and left in. I was going to rename them later, but had no idea that that was going to influence the outcome. :smile: