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I'm trying to work out a way to generate a mask based on a color ID texture in the material editor (not the compositor). What I'm trying to achieve is have a node group I can re-use which has two parameters, the first parameter is the color ID texture and the second parameter is the color from the texture I want to generate a mask from.

I've included an illustration: enter image description here

I got it working for some colors (such as red, green, or blue) but it didn't work in all cases, I also had a problem where the mask would show up properly when previewing it through an emissive shader but wouldn't show up when viewed through a normal diffuse shader.

Thank you for your time.

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  • $\begingroup$ so do you need to improve that IDtoMASK node to work with all colors ? $\endgroup$ – Chebhou Feb 15 '15 at 13:29
  • $\begingroup$ Exactly, it has to work with any input color, basically I need it to extract the selected input color from the color ID texture and output a grayscale mask. There's a similar node in Substance Designer but I don't remember what it's called. $\endgroup$ – Spiderhund Feb 15 '15 at 13:41
  • $\begingroup$ see the answer and adjest its output to get gray scale , i get some work to do now $\endgroup$ – Chebhou Feb 15 '15 at 13:47
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Two independent node groups for creating a mask based on a color and a texture :

material setup :

enter image description here

the first node group outputs boolean 1/0 ( all comparisions are "less than "):

enter image description here

the second node group outputs grayscale :

enter image description here

adjust the sensitivity/clipping to get a good result "sensitivity is added to overcome errors due to rounding the numbers"

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  • $\begingroup$ @Spiderhund use the eyedropper to pick the exact color from the uv/Image editor $\endgroup$ – Chebhou Feb 15 '15 at 13:49
  • $\begingroup$ Thank you for a quick response! It works much better than what I had before, I noticed that it selects multiple colors though, for example if I choose the orange color it actually selects the blue color instead and if I choose the blue color it selects both the blue and the cyan color. $\endgroup$ – Spiderhund Feb 15 '15 at 14:06
  • $\begingroup$ @Chebhou can this be done without separating colors with something like vector math? $\endgroup$ – Bithur Feb 15 '15 at 14:06
  • $\begingroup$ Alright if I add an inverted between the "Absolute" node and the "Greater Than" node I can isolate the exact color I want using the sensitivity slider. Thank you for your help! $\endgroup$ – Spiderhund Feb 15 '15 at 14:32
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    $\begingroup$ @Chebhou Thank you! This is exactly what I needed! $\endgroup$ – Spiderhund Feb 15 '15 at 16:08
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wow, i used an other method but mine is so small i'm ashamed of how simple it is :), but i have tested it with different shades of some colors like dark blue and light blue and it worked well. anyways its like thisID map mask node

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