I have a few problems with understanding the materials/textures thing.
How can I set reflection maps etc? I know how to make a texture have bump mapping (click on the nor button) but I totally do not understand how to set the other maps. In 3ds max there is clear tab for each1. I have been looking at the online reference but I still don´t get it… Does it depend on the 8 channels for textures?
If you want to do envmaps for reflection, you make a new texture and set the type to envmap.
I think that the “secret” (or at least the reason for that particular flat-region on my forehead…) is the fact that each material can have more than one texture assigned to it at the same time; each texture perhaps affecting different aspects of the material’s appearance.
You see, a “texture” is really a signal generator, and its outputs can be applied to any combination of several attributes of the material: Color, Normal, Specularity, and so-on. The influences of each texture on the various attributes can be adjusted using sliders.
So, Blender starts with the basic color and other attributes of the material, then uses the texture(s) to modify those attributes. This determines how all of the objects and faces which reference that material will “look.”
This lets you do some funky things quite easily. Like for example a really old mirror with wavy glass, or one of those gold-flaked mirror-tiles that were so popular in the Brady Bunch days. Just by mixing textures.
If you add an image texture to a sphere the default MapTo function is color. Let’s say the image is a pic of a white daisey flower. Turn off color and turn on Nor and the normals will be affected by the color values of the daisey pic. The darker the colors of the pic the less effect and the whiter they are the more so. Now turn off Nor and turn on Spec, Ref, Emit or Disp (one at a time) and you will see the same color values are used to map those functions to the same faces and to the same degree. The other MapTo functions use model, mesh and shader values as starting values (with lighting, world settings and Z Buffer settings) to modify render output.
Of course, if the shader’s diffuse Reflections are set at greater than 0.00 then those values will show up on all of the material and the daisey texture will only affect the material where it is whiter than the material (this is not strictly correct but helps to explain).
You can set that difference with the Mix, Mul etc and the Var slider and Hard (in the specular shader) will override spec mapped with a texture. Now, if you map a single texture and map it to 2 or more MapTo functions, then all those Mapto functions are subject to any changes in the shaders, Mix, Mul options Var and DVar sliders. If you map only one MapTo function thru the same texture, but a different one (MapTo) in each of X no of different chanells, then each texture chanell can have it’s own MapTo, Mix, Mul and Var values (and mapInput).
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So the layer order does actually have an effect? :-?
Yes it does.
Say you had 2 textures of wood-style stripes, horizontal stripes in the first channel and vertical in the second. The vertical ones would appear over the top of the horizontal ones.
Also (more confusingly) - say you had a texture mapped to Normal in Map Input, set up so that if you look at it straight on it looks white, but if you look at a steep angle it looks black. Then you add a bump-map too.
If the black/white texture is first, then the bumps won’t change the colours - parts of the geometry that are pointing at you will stay white, etc.
But if the bump-map is first, then the black/white parts will change as to whether the bumped surface is pointing at you or not.
Or even weirder, you can have a bumpmap, then the black/white texture, then a reversed bumpmap (click Nor twice in Map To to make the bumps go the other way). The bumps cancel out and the surface is flat - but the black/white texture is still affected. 