I am trying to control the amount glossyness/specular (not roughness) of glass but not able to find any option in cycles. I have tried both the traditional glass shader and the new Principled BSDF shader - none of these seems to let you control the amount of reflection on glass.

I understand that it might not be physically accurate but is there a way to do it?

Here is the blender scene in case anyone wants to examine the setup. http://pasteall.org/blend/index.php?id=47771

Unable to control glossyness of glass


1 Answer 1


If I understand you correctly, you can simply mix a Glass Shader with a Refraction Shader. The factor will determine how reflective the glass material is:

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  • $\begingroup$ As for realism, there might be an anti-reflective coating on the surface. You probably can't get zero reflection IRL, though $\endgroup$ Commented Sep 9, 2017 at 22:44
  • $\begingroup$ True, I thought it may not be physically accurate. That's why it's not possible in Principled BSDF. But in real life situation, the glossyness of the glass may be too much to look real!! $\endgroup$
    – saicode
    Commented Sep 10, 2017 at 11:36

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