The keyword wood specifies a pigment pattern of concentric rings like rings in wood. The color_map specifies that the color of the wood should blend from DarkTan to DarkBrown over the first 90% of the vein and from DarkBrown to VeryDarkBrown over the remaining 10%. The turbulence slightly stirs up the pattern so the veins aren't perfect circles and the scale factor adjusts the size of the pattern.
Most patterns are set up by default to give you one feature across a sphere of radius 1.0. A feature is very roughly defined as a color transition. For example, a wood texture would have one band on a sphere of radius 1.0. In this example we scale the pattern using the scale keyword followed by a vector. In this case we scaled 0.2 in the x direction, 0.3 in the y direction and the z direction is scaled by 1, which leaves it unchanged. Scale values larger than one will stretch an element. Scale values smaller than one will squish an element. And a scale value of one will leave an element unchanged.
The pigment identifier DMFWood4 has already been scaled down quite small when it was defined. For this example we want to scale the pattern larger. Because we want to scale it uniformly we can put a single value after the scale keyword rather than a vector of x, y, z scale factors.
Look through the file textures.inc to see what pigments and finishes are defined and try them out. Just insert the name of the new pigment where DMFWood4 is now or try a different finish in place of Shiny and re-render your file.
Here is an example of using a complete texture identifier rather than just the pieces.
Obviously, we cannot try them all. It would take a tutorial a lot more pages to use every texturing option available in POV-Ray. For this limited tutorial, we will content ourselves to just trying a few of them to give you an idea of how textures are created. With a little practice, you will soon be creating beautiful textures of your own.
Create a file called texdemo.pov and edit it as follows:
Giving this file a quick test render at 200x150 -A we see that it is a simple red sphere against a green and white checkered plane. We will be using the sphere for our textures.
Rendering this we see a three-color hexagonal pattern. Note that this pattern requires three colors. Now change the pigment to...
Looking at the resulting image see that the plane now has a brick pattern. Note that we had to rotate the pattern to make it appear correctly on the flat plane. This pattern normally is meant to be used on vertical surfaces. We also had to scale the pattern down a bit so we could see it more easily. Feel free to play around with these color list pigments, change the colors, etc. until you get a floor that you like.
Rendering this we see that it gives us an interesting pattern of vertical stripes. Try changing the gradient direction to y. The stripes are horizontal now. Try changing the gradient direction to z. The stripes are now more like concentric rings. This is because the gradient direction is directly away from the camera. Change the direction back to x and add the following change to the pigment block.
The vertical bars are now slanted at a 45 degree angle. All patterns can be rotated, scaled, and translated in this manner. Let's now try some different types of patterns. One at a time, substitute the following keywords for gradient x and render to see the result: bozo , marble , agate , granite , leopard , spotted , and wood (if you like you can test all patterns listed in section "Patterns" ).
Rendering these we see that each results in a slightly different pattern. But to get really good results each type of pattern requires the use of some pattern modifiers.
The frequency modifier determines the number of times the color map repeats itself per unit of size. This change makes the bozo pattern we saw earlier have many more bands in it. Now change the pattern type to marble . When we rendered this earlier, we saw a banded pattern similar to gradient y that really did not look much like marble at all. This is because marble really is a kind of gradient and it needs another pattern modifier to look like marble. This modifier is called turbulence . Change the line frequency 3 to turbulence 1 and render again. That's better! Now let's put frequency 3 back in right after the turbulence and take another look. Even more interesting!
But wait, it gets better! Turbulence itself has some modifiers of its own. You can adjust the turbulence several ways. First, the float that follows the turbulence keyword can be any value with higher values giving you more turbulence. Second, you can use the keywords omega , lambda , and octaves to change the turbulence parameters. Let's try this now:
Rendering this we see that the turbulence has changed and the pattern looks different. Go ahead and play around with the numerical values of turbulence , lambda , omega , and octaves to see what they do.