Black Spot on a Character

[N.Barantsev]

Hi! There’s a black spot on the character’s neck. Don’t understand what the problem is.
The textures are fine. I even removed all the textures to make sure the problem is not that. The mesh is also fine. The normals are correct. And it doesn’t depend on the lighting. It’s just always there.

Here’s how this part looks in cinema 4D

[SupportiveEntity]

Hey there @N.Barantsev! Welcome to the community! So you’ve already checked most of the usual suspects, so we’re going to have to check up to make sure there aren’t two faces (even the correct normals) over them, but that’s likely not it since the shape of the darkness is just in the recessed bit of the neck. Does your character have a normal map attached? If so could you deactivate it for a bit to see if that has any effect?

[3dRaven]

• Are there any overlaps in the UV channels near the neck mesh?
• Does this error go away if you scale the model. How large is it compared to the default unreal objects?
• Did you do a non-manifold check of the mesh before exporting?
• Does your model have any vertex color painting exported alongside the model that you cannot see in the current c4d view?

[N.Barantsev]

Hey! Thank you! That is my first experience in UE.
On the top screenshot the material is just a solid color with all the textures detached, normal texture is detached as well.
And I checked the mesh, the geometry is correct.
There was a blend mesh applied to geometry but it was a different part of the model. And I removed it and reimported it to UE and this artefact still remained. So still a mystery, what causes it.

Another fun fact is that today for another scene (the character is for a video that I make in Unreal) I decided to make a more accurate rig and I split some parts of geometry like parts of clothes and repainted the weights for them.
And when I imported this new model into UE, this thing on the neck was gone. And I don’t understand what changed really.

I still need to understand how to correct this one, because it’s already animated and I don’t have time to remake the whole animation for this scene.

[N.Barantsev]

Hi!
Thanks!

• No overlaps in UV.
• It’s real world scale. And scaling doesn’t seem to affect it
• I haven’t done the non-manifold check before I exported. But I have now, after you mentioned it) and no non-manifold geometry was found
• There was no vertex paint, but there was a blendshape applied. It was applied to the scarf though. And I removed it and exported again and in UE the black stain still remained

Also, I don’t know how to interpret it. I wrote about it in the previous comment. The initial mesh was combined and I broke apart some parts of it to make a more precise rig for another scene, and repainted the weights for these parts, and after exporting that new rig that artefact was no longer there.

I could use this new rig but the problem is I cannot remake the whole animation that I already have for the old rig because it’s just to much work, so it would be great to figure out how to fix this one)

[3dRaven]

Is the black spot visible in unlit mode?

[N.Barantsev]

@3dRaven

isible in u

good point. no, it’s not. does that mean it’s something related to ambient occlusion?

[3dRaven]

Well it’s definitely something to do with lighting. It could be very low resolution self shadowing.
What is your lighting setup? Try different shadow settings for your directional light.

if you toggle shadows off on your light, see if the black spot disappears.

Make sure you have "Generate Mesh Distance Fields on in your project settings if using lumen.

[N.Barantsev]

First time I noticed it in level with several light sources. I switched them all on and off but it didn’t go away. Now I’m just testing it in a default setup with a directional light and a sky light. When I switch off the shadows for both of them it looks like this.
Generate Mesh Distance Fields on

[3dRaven]

Is the skin material using sub-surface scattering? (SSS)

The difference is either mesh based or material based.

Try temporarily replacing the skin material with a default grey material and see if the black blob clears up.

[N.Barantsev]

No, it’s not the material. It’s the first thing I checked. And this area is not even always black. It just recieves light in a wrong way, like if there’s something wrong with normals but the normals are ok.

[3dRaven]

Perhaps it’s a smooth group cutoff.

Not sure how c4d handles it but Maya has hard edges and 3dsmax has smooth groups. You might have some edge information imported from c4d that could have been changed even by accident.

Also can you turn on normal direction visualization in c4d? Perhaps it’s set to 2-sided there and it’s not showing up as flipped in the viewport?

You might even have hidden faces in c4d that become visible on import. (Maya can hide selected faces or elements)

[N.Barantsev]

Hi!
I think I’ve figured it out. It’s pretty basic, but I’ve learned it the hard way) I’ve read that it’s important to import the character first, and then the animation separately. I did this for a while but I didn’t know why it should be done exaclty like that. So I tried to save time and import the model and animation in one file and it seemed to worke fine, so I just started doing that. Today I suddenly remembered this and it struck me, I’ve tried importing it the correct way, and of course the artefact was gone.
Thank you for your help! I’ve learned a bunch of stuff in the process.

[3dRaven]

Congrats on getting it working correctly.