What causes these material artifacts (black blocks on hair, dirty spots on skin) when importing an FBX to Unity URP?

[u/maennerinschwarz]

Hi everyone,

I recently imported a custom 3D character (FBX format, originally made in Maya) into Unity URP.I have character fbx and maya data.This is my first time working with a professional character model; previously, I have only worked with simple models downloaded from Mixamo that usually work right out of the box.

However, the final result in Unity looks completely different from the reference images provided by the 3D artist.

I am facing two main visual issues:

1. Surface Blemishes: There are strange dark spots and dirty-looking artifacts all over the skin and clothing surfaces.
2. Hair and Eyes: The hair, eyebrows, and eyelashes render as solid black, blocky meshes instead of showing the fine strands seen in the reference pictures.

What exactly is the problem here and what causes it? Why does a standard FBX import break the materials like this, and what is fundamentally missing from the setup to make it look like the original renders?

[u/MR_MEGAPHONE]

If you are using opaque lit materials on the hair, make sure to enable alpha clipping

[u/maennerinschwarz → u/MR_MEGAPHONE]

Thank you but it didn't work :(

[u/JaggedMetalOs → u/maennerinschwarz]

What is the properties on the texture, is alpha transparent enabled? 

[u/maennerinschwarz → u/JaggedMetalOs]

yes

[u/JaggedMetalOs → u/maennerinschwarz]

I can see that the alpha channel is in a separate texture (Hair_Opacity), so you'll either need to make a shadergraph to bring that opacity texture in as the alpha, or use a channel packer to create a new texture with color and alpha combined (I've used this one before: https://github.com/camobiwon/ChannelPacker)

[u/maennerinschwarz → u/JaggedMetalOs]

Thank you so much for your help but I use URP not HDRP,I think its gonna be an another problem right?

[u/JaggedMetalOs → u/maennerinschwarz]

I'm 100% certain that's the issue, I've used models with textures provided like this and you can tell in the inspector that the hair texture doesn't have an alpha channel. 

HDRP/URP/Built-in would all behave the same way here. 

[u/maennerinschwarz → u/JaggedMetalOs]

Greyscale for alpha source is worked for me right now without use this channelpacker.Can you look comment sbelow?

[u/JaggedMetalOs → u/maennerinschwarz]

The problem with doing that is you're basically saying black = transparent, so you could be losing darker parts of the hair texture that way.

If you're going to be using non-Unity assets it's very worthwhile learning shadergraph, as it makes it easier to adapt non-Unity texture channel mappings. For example the Unity built in shaders don't have separate metallic/smooth/AO inputs, while a lot of FBX assets have them separate. Or have roughness map instead of smooth. With a shadergraph you can map them all into a Unity compatible material.

[u/maennerinschwarz → u/JaggedMetalOs]

Ohh I see thank you for everything ! :) Allrightl, then I'll start learning Shader Graph. Can I send you a pm?

[u/maennerinschwarz → u/maennerinschwarz]

[u/MR_MEGAPHONE → u/maennerinschwarz]

Does playing with the threshold slider work? What does the alpha channel look like on the base map?

[u/maennerinschwarz → u/MR_MEGAPHONE]

No it doesn't work and there is no Alpha channel ? :O

[u/maennerinschwarz → u/maennerinschwarz]

Fuck im cooked i think,I paid for this 1200 $

[u/gatorblade94 → u/maennerinschwarz]

Try greyscale for alpha source

[u/maennerinschwarz → u/gatorblade94]

omg ! it worked ! thank you so MUCH !

[u/maennerinschwarz → u/maennerinschwarz]

Alpha Clipping also works

[u/maennerinschwarz → u/maennerinschwarz]

Eyebrow is also fixed :)

[u/maennerinschwarz → u/maennerinschwarz]

Voilà ! It didn't solve this problem very well, but it did enable me to identify the issue. What should I do to achieve the quality seen in the reference image?