Painting second material on an existing UV?

I want to paint glowing tattoos on my character. He already has a UV texture on him.

Like the title says, I want the second material to put off a little light and have no shadows, so it needs to be a new material.

Can someone outline the steps I need to take?

Sorry if this is a noob question, I am still not good at navigating Blender. Everything I manage to do is done by following tutorials very closely. I can’t find a tutorial for this precise issue.

The closest thing I could think of was how people paint multiple textures on terrains, but I wasn’t finding step-by-step tutorials that fit my project.

It doesn’t have to be a new material. You can do it with a new material, on a duplicated mesh, but that’s more trouble than it’s worth and bad for performance.

Let’s say you’re using Cycles nodes materials. Draw out your tattoo on a new image, using your original UV map. Then add a few bits to your nodes, right before outputting to surface. Do a lookup on your tattoo texture and use it as the factor for a mix shader node mixing between your original material’s shader and an emission shader.

EDIT: This post is now irrelevant, because of new progress. :slight_smile: Mostly I was saying thanks for the help, what you say seems to make sense.


Okay, your advice to use a mixer really helped! I was able to get the tattoos overlayed successfully, and now I’m just a bit lost on the last steps. I followed a YouTube tutorial ( ) to help me make sure the nodes are connected right.

I would ask one more thing, if you have a chance, that you could explain in steps how I am to connect the nodes to get the tattoos only to emit light? I tried to follow what you said earlier and it keeps turning the whole material black. I’ll attach an image showing the way I interpreted how to set it up.

I think I might be mixed up on the shader of my original texture as you refer… I am was using a principled bdsf just to try it out and didn’t have a shader applied yet. This is my first experience with shaders so far.

Edit: not sure if it’s relevant but whether I connect the alpha or the color of the tattoo texture to the mixer’s factor, it’s still black.

Don’t know what your texture looks like. Does it have an alpha? Of 0 everyplace there’s no tattoo and 1 everyplace there is tattoo?

I can just edit something up in a jiffy…

So here I’m using a texture-- the one pictured-- to mix between my main shader and an emission shader.

I tried to hide the irrelevant parts of my huge shader mess-- whatever your main skin shader is, just consider it to be occupying “MAIN”'s space. It’s this simple. Use a black and white texture as the factor for a mix shader node.

Edit: oh. i see. You’re using a mix RGB node. You want a mix shader node.

Mix shader not mix rgb… ohhh lol. Derp!

Thank you so much! It works!!! :slight_smile:

Looks good.