How I make a Reflection map mask?

Dantert

I found a lot of tutorials about reflection maps but nothing about a "reflection map mask", I need to know what it is for a work, someone knows how it works and can attach an example about it please?
I would be eternally grateful to you!
Thanks in advance

almighty_gir

a reflection map mask is just a grayscale map that they use to define where reflections are used, or how much of that reflection is used.

black means no reflection, white means pure reflection, anything inbetween means something inbetween.

take a texture map that has, for example... polished metal, polished leather, and cloth. the polished metal would be almost white, the polished leather would be dark grey, and the cloth would be almost black.

EarthQuake

It depends on exactly what they mean by reflection mask. A reflection mask in the sense that Gir is explaining it is the same thing as a specular mask. Really for most uses it would be redundant to have both (specular reflection is one thing, not two things, though in game engines specular often refers to reflected light from dynamic light sources and reflection to light reflected from cube maps/image based lighting).

A specular occlusion map is something entirely different however, which is a map used to mask where reflection occurs (independent to *how* reflective a material is, which is what a specular map or gir's explanation of a reflection map do).

Some 3d apps have presets for baking out reflection occlusion maps, similar to ambient occlusion maps, you may also need to do a bit of hand editing to get a good reflection occlusion map as well.

Modo's help doc has some good examples of various types of occlusion, including reflection occlusion. http://docs.luxology.com/modo/501/help/pages/shaderendering/ShaderItems/Occlusion.html

EarthQuake

Yeah its really highly specific to how your engine/shaders are set up.

Do some assets use a simple cube map, but no gloss or gloss-blurring of the cube map? In that case you may want a texture to control where that cubemap is applied, and really only apply it to very glossy/reflective materials.

Do you have a standard image based lighting workflow where the gloss map controls the blurriness of the cubemap? You may still want to bake in some occlusion to your specular map to avoid strange cubemap reflections in occluded areas, or use a reflection occlusion mask as a separate texture.

Do you have a more advanced reflection system, perhaps using screen space reflections to avoid illogical reflections? In that case you may want to use very little or even no occlusion for the specular reflections at all.

So yeah as Per says, ask the client, asking questions is good.

Dantert

Thank you all guys! Now it's all clear You're the best!