this post was submitted on 29 Apr 2025
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Any clue why I'm getting these bald spots? (lemmy.world)
submitted 4 weeks ago* (last edited 4 weeks ago) by RampantParanoia2365@lemmy.world to c/blender@lemmy.world
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I'm getting these bald spots on the back of my separate scalp mesh. The hair is not combed behind the scalp, it's just not there at all. Weight painting is totally red for both density and length, and I've tried disabling modifiers like frizz and noise, and every other one. Does my model just have bad genes?

UPDATE: The shader was the culprit! The missing hair was simply transparent, but I've switched the short hair to a simple node, and it's all a lot smoother. The complex setup is still on the longer hair.

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[–] Kolanaki@pawb.social 2 points 4 weeks ago (1 children)

I'm interested in the reason for this, now, too, just because I noticed it with the hair in KCD2 on some characters. Whatever it is, OP, even big pros have it.

[–] RampantParanoia2365@lemmy.world 2 points 4 weeks ago

check out my update, it was just the shader, which was creating a lot of variation for the hair. Apparently it made some of it transparent.

[–] Mothra@mander.xyz 2 points 4 weeks ago (1 children)

I've only got basic experience with Blender's grooming system, but here are my would -be checkpoints:

  1. Check the UV map is in good condition, that those bald polygons are properly mapped;

  2. Check normals are facing the right way for the entire surface

  3. Check the hair isn't poking through the other side or lying parallel to the surface, which seems obvious and you probably already did;

  4. Check you are displaying all hair curves on your viewport, that your limits are enough for the amount of curves

[–] RampantParanoia2365@lemmy.world 1 points 4 weeks ago (1 children)

I figured out it was the shader I was using, creating too much variation, and those parts were transparent. I put a simple shader on the short parts and it all looks a lot smoother.

[–] Mothra@mander.xyz 1 points 4 weeks ago

Awesome you figured it out! Strange to hear it was the shader but hey good job troubleshooting

[–] CreatingMachines@fedia.io 26 points 4 weeks ago (1 children)

You know, I just read the title, saw the picture, and thought you modeled your own head to show the bald spots you were suffering from.

[–] RampantParanoia2365@lemmy.world 4 points 4 weeks ago

ha, and you probably noticed "bad genes"

[–] InternetCitizen2@lemmy.world 6 points 4 weeks ago (1 children)

Hey I asked you to be more flattering when you draw me! /j

[–] RampantParanoia2365@lemmy.world 5 points 4 weeks ago* (last edited 4 weeks ago)

you are more flattering from the front I think. just look at those pretty eyelashes...

[–] RampantParanoia2365@lemmy.world 11 points 4 weeks ago

I'm thinking of creating a community called Mysteries of the 3D Realm, for inexplicable issues I seem to have on the reg. This will be post #1.

[–] pennomi@lemmy.world 8 points 4 weeks ago* (last edited 4 weeks ago) (1 children)

It’s hard to say for sure, I’m not very practiced on hair in Blender. But it looks quite similar to issues I’ve seen with baking normal maps where the low res mesh clips through the high res one, causing little diamond spots like these bald spots. Could it be that the target mesh is on the wrong side and therefore not finding the target location to plant a hair follicle in?

Again, I don’t use Blender hair in my line of work so I may be way off.

[–] RampantParanoia2365@lemmy.world 5 points 4 weeks ago (1 children)

so the scalp mesh is just a duplication of the original head mesh, and i have it shrinkwrapped to the head. The hair is only growing out of the scalp, which is the target, and even if I isolate it, the hair is just not there. and you can see in the first image where the guide curves are, which Blender interpolates, and even if those were missing, it shouldn't do this. i hope i answered you!

[–] pennomi@lemmy.world 4 points 4 weeks ago (1 children)

I assume removing the shrinkwrap doesn’t fix anything?

Anyway, I doubt I have the expertise to solve this one. Good luck!

[–] RampantParanoia2365@lemmy.world 4 points 4 weeks ago* (last edited 4 weeks ago)

Nope, and that doesn't effect how the hair spawns, anyway. thanks, appreciate it regardless!

[–] RampantParanoia2365@lemmy.world 8 points 4 weeks ago* (last edited 4 weeks ago)

my weight maps and edit mode, no blue spots or funky geometry, no double verts...