I watched a Quoxel(free alternative tonsubstance painter, pbr smart materials texturing) and he had some atlas with neon colours that could be detected by the program.
I.e metal parts neon green, rubber parts neon pink, some other parts neon pink etc.
What is that tecnique called? Seems super useful when I wanna atlas stuff togheter and then do texturing, since I can just use a colour for all the UV's of the same type etc.

Anyone knows what I'm talking about?