Need help with rigging and weight painting

Hello everyone, I’m a newbie and I want to use an MMD model I found online to make a GMod playermodel. So far I’ve managed to rig it and weight paint most of the body (everything except the arms, neck and head). My problem is that no matter how I paint the elbow, wrist, finger and neck joints, they keep creating weird random figures stretching out or break down completely when I try to rotate them. Could anyone help me out? Thanks in advance. Here’s how the broken model looks and how it’s supposed to look normally and what I want to weight paint completely

How does it deform in Blender? If it deforms well in Blender but not in Gmod, then it’s something to do with Gmod, right? (In which case, I can’t help you. But if it’s something in Blender, I probably could…)

I haven’t reached the point where I can use it in Gmod yet, I need help on making it functionally rigged in Blender, so yeah, if you can, then please

Oh, okay, I guess you’re just using some weird bone display that I haven’t seen before.

Upload a .blend someplace and let me know and I’ll look.

Here it is. I am using a ready Source playermodel bone system(?) so that the model can be used in-game

It’s just that your weights aren’t very good.

Probably one of the reasons for the poor weights is that you don’t quite understand how Blender handles weights. It lets you paint unnormalized weights, then normalizes them only at the time of deform or export.

So let me give you an example. When I travel up the back of your calf and look at the calf weights, I see that it’s weighted .768, .8, .657 to the calf-- but weighted 0 to all other bones. So when this gets normalized, all of those weights are the same: 1.0 to the calf. (Take the weight, divide by the sum of all deforming weights to get the normalized weight. You can get Blender to do this for you with weight paint’s Normalize All tool.)

If you want to weaken the calf, you can’t just weaken the calf, not when it’s not weighted to anything else; you have to also strengthen the thigh.

There are some tools for normalized weight painting in Blender, but personally, they’ve never made much sense to me. When I do manual weight painting (which I try to avoid, autoweights are awesome), I usually paint from the root out, in vertex mode (‘v’), using linear gradients on Add mode (alt LMB is a handy shortcut), then normalize all with active locked as I go.

When I need to tweak those weights, I tend to do it using a multiply brush (on weight 0.0, that’s kind of a weird thing) to weaken weights, rather than strengthening weights. It works because I already have verts assigned roughly correctly, so at that point, if I weaken one, the others will take up the slack.

Note a few other pitfalls here. That’s a weird armature, with a lot of bones, and the way you have it set up, it’s not easy to see what those bones are supposed to refer to. If it’s comfortable for you, great, but if it’s not, consider reworking the rig a bit just so you can understand it. Additionally, this is a mesh with a decent amount of overlapping meshes which might be tricky to weight paint in a way that keeps them from clipping into each other. You might try weight painting with “limit selection to visible” disabled. Or you might consider separating the clothes to a different object and copying weights with a data transfer once you’re done.