I have a metal pyramid which I'm trying to make slightly covered with sand dust. But I don't need it everywhere, so I decided to use a mask. I've never used masks before. I'm using a texture for this dust as shown in the video (https://www.youtube.com/watch?v=ZmrCoGj9m2Y) BUT: I have base metal material with normal displacement from a noise texture, I have a dust img, I have a mask. When everything is set up and I paint the texture I also paint black background. In the video he has clean dust only show up on the model. He has nodes to make it appear only in sertain places (I use paint for that) but he doesn't have anything that makes it show dust without black bg So how do I make it so when I paint only dust shows up and between it is my base metal material and not black bg of the texture?

Example of a stroke

Nodes for the pyramid


Your node setup is basically correct, however, I think the "Black background" that you are seeing is because the nodes that define your dust are a mix between a diffuse shader and... nothing!

I will call the mix shader node on the left of the image the "first mix shader node", and the mix shader node on the right of the image the "second mix shader node".

So you are successfully mixing between the nodes that make up your base metal (second slot, on the second mix shader node) and the nodes that make up your dust (first slot, on the second mix shader node). But your dust is itself a mix between an Orange colour and no shader at all (which shows on the render as blackness). So your dust is coming out as orange mixed with black.

To fix - plug another diffuse shader into the second socket on the first mix shader node. Give it a slightly different orange colour. You should get results more like what you wanted.

  • $\begingroup$ So what you suggested worked But that's not what I'm looking for I now have Dark Brown "particles" of dust (you could see the on my screenshots) and Light Brown space between (I added a Diffuse shader as you suggested, of light brown colour) But can I make it have no colour instead? so that we see "particles" of dust but no black or light brown inbetween but rather our shiny metal of the pyramid, so that we have an effect of dust on the model? Is that possible? The guy's render looks like he has exactly that and I can't get my head around it. $\endgroup$ Aug 21 '19 at 12:45
  • $\begingroup$ Yeah, there are lots of options. One option - you could just have a single shader for your dust material. Delete the first mix shader node, plug the dust.png texture node into the diffuse shader colour input, and then plug that into the second (and now only) mix shader node. Another option - keep your two tone dust material like you have now, and use a colour ramp node after the dust.png texture to push the black/white value up to a level that you are happy with. Bit hard to describe on here. $\endgroup$
    – Lewis
    Aug 21 '19 at 16:18

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