So I'm modeling a space ship, and I want to make a pattern on it glow with an iridescent sheen only when in direct light. When strong light hits that specific area, I want a bunch of lines of iridescent patters to appear, but not where there isn't strong light. I hope this makes sense. I've been trying a lot of different things, but none of them work. Any suggestions would help.

  • $\begingroup$ can you post a screenshot or example image of what you're looking for? $\endgroup$
    – Jakemoyo
    Aug 17, 2022 at 17:16
  • $\begingroup$ Speaking generally, almost every shader reacts to the strength of light. For doing weird stuff, like emission based on light strength, you would either need shader-to-RGB (Eevee, easy and convenient) or compositing+re-render (in Cycles or Eevee, less convenient.) What rendering engine are you using? $\endgroup$
    – Nathan
    Aug 17, 2022 at 17:47

1 Answer 1


As Nathan mentioned in his comment, you can make use of Shader to RGB. Used a Diffuse into Shader to RGB into a ColorRamp (your choice whether to use linear or constant) like a basic Toon Shader setup, but only using 2 shades - black and white. Use this as a mix factor between your base material and your Iridescent material.


Here's the setup in its entirety with a slightly better Iridescent texture:


EDIT - Sorry, I just saw you wanted a "glow". If you want this, try mixing your glossy shader with an emission shader of the same color. If you just want the "glow sheen" to overlay the current material (without replacing it entirely), you can try something like the setup below:



You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .