Gloss and Fresnel when it comes to Specularity and Reflections

kodde

Hey guys,

I'm doing some planning on a shader and I cannot decide upon if I should have a separate Gloss/Roughness for the specularity and reflections or if they should use the same value/texture?

Same issue if I want to modulate the specularity and reflections with a fresnel term, do I want the same amount of frensel modulation on both or keep these separated?

I could make these separated but I'm leaning towards not. I mean, they both simulate what in reality is the same thing more or less? Can anyone think of a case where I would want to tweak these parameters independently from each other?

Thanks for your input.

cman2k

Most engines let you tweak these independently.

That being said, I prefer to keep them tied together and tweaked/modified so they work as expected. As you said, they influence the same phenomena and when they are separate it's just way easier for a novice to get them out of sync and not understand why things "don't look right".

I have thought about this issue in the past and haven't found many times when I really want them to be separated. In the current game I am working on, I have tied them together entirely. To do this I did do some tricky stuff in the shader (like clamping for pure black/pure white in the roughness and what not).

It's definitely a preference thing. An experienced artist may prefer complete control, but from a usability standpoint less values to tweak can make it easier to avoid undesirable results and keep things standardized.

kodde

Thank you for your feedback. I agree with what you're saying. I'll go for keeping them together unless someone points a good reason not to.