Does anyone here know of a tutorial or other document that explains in depth the various available shaders and what they are good for simulating? I checked the manual and it was of no help.
Have a nice day.
Not sure about depth, but over at Blenderunderground.com they’ve got the Blender Basics series. Part 5 says a bit about each of the shader types as I recall.
There is quite exhaustive overview:
http://wiki.blender.org/index.php/BSoD/Introduction_to_Materials/exercise_2#Intro_to_shader_types
Here is a quick overview of texture channels:
Color Channel changes or influences the color of the object. The amount of influence it has can be edited with the col slider.
Normal (‘Nor’) Channel affects the appearance of the surface. This would be also known as the ‘bump’ channel.
Csp (Specularity Color) influences what color the specular highlights are.
Cmir (Mirror Color) influences the color that objects are reflected as.
Ref (Reflection) is kind of like the diffuse setting. It influences what areas reflect more or less light (its like setting the ‘ref’ value on the diffuse shader).
Spec influences where and how much specularity something receives.
Amb influences the amount ambient color an object receives (allow mapping of the amb attribute)
Hard affects how hard or soft a specular highlight is. Its like the gloss/glossiness channel.
RayMir causes the texture to effect how much reflection (raytraced reflection, not diffuse) a material has.
Alpha modifies the alpha value, making things more or less opaque.
Emit determines how much light to emit from a face (blender will not automatically light up surfaces like something like yafray will, though). Its like the luminosity value.
Translu maps to the translucency attribute of an object which determines how textures blend with things behind them.
Disp is displacement mapping. Blender does not have micro-polygon displacements, so anything you plan to use this with must be heavily subdivided to provide the necessary mesh resolution.
UV mapping behaves just a procedural texture does. You can create a UV map, map it to the UV coordinates (as they are set out in the UV editor) and then map it to really any of the values above. It is a good way of getting exact values where you want them. The most common of course are the color, spec, bump (nor in blender), alpha, and diffuse (ref in blender) maps, but on occasion there is necessity for others.
For instance, if you are say texturing a soda can, when you look at it, most cans have color on them that actually changes the color of specularity. So for this, you UV map a model with color, but then also map the color map to the csp channel and the color of the UV map will influence the color of the specularity.
Thank you, both those sites are great.
The word shader is a bit misleading. It’s actually a mathematical function of some kind that can be applied to control many different parameters of the rendering process; not just light-and-shadow.
Personally, I think that the most useful thing to experiment with is, not the shaders themselves, but the many different ways in which shaders can be applied. There’s a very large number of parameters that can influence a render. Consider what is the purpose for each one. When you look at a scene in real-life, consider (say…) not only “how does (say…) the light look,” but also, “how does it vary” and “what causes it to vary as it plays across this object?” That sort of thing will trigger your powers of observation in a different sort of way.