Weight paint: Subtract adds paint + X mirror doesn't work properly

Support Animation and Rigging
1

Hello there.

I’m currently working on rigging my character, but I have run into two problems that I hope I can get help with.
New user, so screen shots can be found here:

[Album] imgur.com
  1. The Character
  2. The x mirror problem
  3. The Weight paint problem

Problem 1:
I’m fairly new to blender, so maybe I’m just being stupid and the fix is super simple. But, when I have x turned on to mirror the paint from the right side to the left side, all it does is add the paint on both sides to the bone on the right side.

Problem 2:
This is really a headscratcher for me. So the problem lies, when I try to weight paint the left leg, it seem to influence her shirt and holster straps, so I try to use the “Subtract” brush, but all it does is ADD weight painting to the shirt, the belt buckle and metal clamp(Or whatever those belt things are called), instead of subtract. Also, it doesn’t subtract from the boot around the bone as well.

If it helps, here is a quick progress of the character modeling:
First I made the body. From there I modeled the clothes, hair and facial features as separate meshes. Once everything had be modeled and textured, I saved the model as a separate file where all of the meshed had been joined into one mesh. (Except the pupils, eyelashes and eyebrows as I don’t know how rigging facial animation works yet, and the hair is also a separate mesh) Then I started adding the armature into bones around the mesh, naming them and using the feature “AutoName Left/Right” and “Symmetrize”
Now when I try to weight paint, I run into the problems mentioned above.

Hope you can help.

2

Problem 1: First of all, this is not a symmetrical model. Now, there may only be some elements that are symmetrical, but any levels of asymmetry suggests to me that, probably, other stuff is asymmetrical as well. (It is extraordinarily easy to end up with unnoticeable asymmetry.)

I don’t do mirrored weight painting myself. If I have a symmetrical model, I keep a live mirror modifier and just paint one half. If I have asymmetrical details, these are likely to acquire their weights via a data transfer (probably, applied) rather than manual painting. If I have a fully asymmetrical model, then symmetrical weight painting isn’t going to do anything remotely good anyways.

It would not surprise me if there are symmetry options that mean that weights get painted to the appropriate bone. But, again, I’d strongly recommend just not using symmetrical weight painting. It’s never necessary (because live mirror mod); in the situations where it appears to be necessary, where you can’t use a live mirror mod, it’s probably not going to work anyways.

Problem 2: It sounds like there are probably a lot of things going wrong. A file, saved at the point immediately before things start to go wrong, along with a video demonstrating what you’re doing that ends up giving you wrongness, would probably go a long way.

However, I should mention that there are some issues with normalization. If a part of a mesh is weighted to only a single bone, subtracting weight doesn’t do anything, because there’s no other bone to take up that difference. If you’re using autonormalize weight painting (another thing I never do, I hate it with a passion), then it’s likely that subtraction is never going to lead to even any apparent changes in the weight paint colors on your mesh.

But-- painting on one part of a model should never, ever affect a different part, so the file + video would let us see what’s going on, and replicate it.

3

(Man, the limitations of being a new user is tough. 2 links only)
Okay I see, so its not fully symmetrical so its not advisable to use that function. I guess that makes sense, plus it would be more accurate to paint each part individually. Thanks for the advice :slight_smile:

Now, the weight painting problem. First the files:
https://drive.google.com/drive/folders/1gx3QnMcc419DpS6hBOpxAMSe5RIYVnW1?usp=sharing
The first called “Seperate_Meshes” are the model before joining all parts into one mesh, in case there is something there that causes the problem.
The second called “Weightpainttest” is the model ready to be weight painted, where the left leg bone is the main problem.

Here are the videos where I demonstrate the issue:
https://www.youtube.com/playlist?list=PLEN47tMN_1JS82qqENsBt7Iz6uG-vrl0a
“Weightpaint1”
First video shows me trying to subtract the shirt as such from the leg bone with no luck. I also try to paint on different parts of the body, then subtract again but no luck.
“Weightpaint2”:
This shows the same, but before the shirt and other parts got weight painted. The holster straps shows to be slightly effected by the leg bone, but as I paint over it, it fully connects to the belt buckle, zipper, shirt and such.

Hope this give more insight to the problem.

4

Okay. I misunderstood what you’re saying. Everything you’re showing in your video is because of what I said above:

You have autonormalize enabled (look on sidebar/tool/options in weight paint mode.) And the part of the mesh you’re painting is weighted to 1 bone (select a vertex and look on sidebar/item/vertex weights in weight paint or edit mode.) So you can subtract all you want, but it’s not going to have any effect. For it to have an effect, you have to weight it to some other bone, so that less Leg.L weight means more weight for some other bone.

Think of it like this: you want it move less with Leg.L than it is. So how do you want it to move instead? More with the leg’s parent, Spine1? Then instead of subtracting weight from Leg.L, add weight to Spine1.

5

Ooooooh, okay. I understand what you mean. I tried adding paint to the shirt from the spine bone, and now selecting the leg bone, the paint from the bone is now gone.
So as you said, if there is no other bone influencing the area, then there is nothing to subtract.

Thank you so much for the help, I hope you have a great day :slight_smile: