OTOY Forums

In a totally newbish manner of speak: what's the theory difference? As a hobbyist without any physical background I currently assume the following:

- Diffuse material is undirected light off the material, in the color of the material. Or bluntly said: just the color of the material without any light reflections, just the light the material emits itself

- Specular reflection is of the same wavelength as the light shining onto the material, pure reflection, unmodified by the material

Is this more or less right?

But that confuses me a bit, because there's also "gloss", which is also just reflection. I don't quite understand the difference and when to use what to create materials (even more complex when using material mixing).

And I don't quite understand specular maps. If gloss and reflection is a characteristic of the matieral, then the calculation process should determine what is reflected where ...

But that only works if we'd model with a gazillion polygons and realistical surfaces ... which we don't have ... so we use bump maps, normal maps and ...... specular maps.

but aren't those kind of fixed to the viewangle when the photo was taken? If I looked at a material in angle A and noticed how it reflects things and take a foto of that to create a specular map .... how can this be valid for angle B which is totally different?

I'm quite confused by these things

Broadly speaki...

Diffuse Material: solid object with completely matt surface. Plain wall for example..

Gloss Material: solid object with shiny surface. From paint to silver, to wet wall. This has a Specularity input which controls how reflectice the surface is, and a roughness input which controles how shiny the surface is. A mirror, for example would be spec 100 roughness 0. A leather coat woul be much less reflective and not as shine, so lower spec and higher roughness.

The maps for these inputs control how reflectice (for the spec channel for example) the surface is over the model. For example on a woman defacement the lips will have a higher spec that the chin.

Specularity Material: is for clear objects. Like glass or water.