Procedural Textures and Natural Phenomena

The following procedures are part of the standard Alias package:

Table 2:

Atmospheric Effects:
Fog
Parametric procedural textures:
Bulge	Checker	Cloth	File
Fractal	Grid	Mountain	Noise
Ramp	Stencil	Water
Solid procedural textures:
sFile	sCloud	sFractal	sRock
sMarble	Snow	Leather	Granite
Volume	sWood
Environment textures:
Ball	Chrome	Cube	Sky
Sphere

Common Texture Parameters

The following texture parameters are common to all texture procedures. They control the texture blur and intensity.

Parameter	Absolute Range	Useful Range	Default	Description
blurmult	-infinity, infinity	0.0, 1.0	1.0	multiplier factor used to blur a texture
bluroffset	-infinity, infinity	0.0, 1.0	0.0	additive factor used to blur a texture
aout	-infinity, infinity	-1.0, 1.0	0.0	value of "a" outside textured area
amult	-infinity, infinity	-1.0, 1.0	1.0	mult value for intensities of single-channel textures.
aoffset	-infinity, infinity	-1.0, 1.0	0.0	offset value for intensities of single-channel textures
rgbout (triple)	0.0, 255.0	0.0, 255.0	0.0	color of shader outside textured area
rgbmult (triple)	-infinity, infinity	-1.0, 1.0	1.0	multiplicative factor for colors, to scale them up or down.
rgboffset (triple)	-infinity, infinity	-1.0, 1.0	0.0	offset factor for colors, to boost the RGB values by an additive amount.

Note that the choice of whether "a" values or "RGB" values are used depends on the feature being textured.

For example, if transparency is being textured, then the "a" parameters are relevant, because transparency is a single channel feature. However, if incandescence were being textured, then the "RGB" parameters would apply, as incandescence is a three channel feature.

Common Parametric (2D) Texture Parameters

The following texture parameters are common to parametric (2D) textures:

Parameter	Absolute Range	Useful Range	Default	Description:
urepeat	-infinity, infinity	-10.0, 10.0	1.0	# of copies in u direction within coverage area.
vrepeat	-infinity, infinity	-10.0, 10.0	1.0	# of copies in v direction within coverage area.
uoffset	-infinity, infinity	-1.0, 1.0	0.0	U offset repeat withincoverage area
voffset	-infinity, infinity	-1.0, 1.0	0.0	V offset repeat withincoverage area
ucoverage	-infinity, infinity	0.0, 1.0	1.0	amount of U surface to be textured
vcoverage	-infinity, infinity	0.0, 1.0	1.0	amount of V surface to be textured
utranslate	-infinity, infinity	-1.0, 1.0	0.0	amount of U coverage area to be moved.
vtranslate	-infinity, infinity	-1.0, 1.0	0.0	amount of V coverage area to be moved.
uwrap	TRUE FALSE		TRUE	flag to wrap texture around U boundaries of coverage area.
vwrap	TRUE FALSE		TRUE	flag to wrap texture around U boundaries of coverage area.
worldspace	TRUE FALSE		FALSE	flag to use world space texture mapping
rotate	-infinity, infinity	-360.0, 360.0	0.0	angle coverage area to be rotated
mirror	TRUE FALSE		FALSE	flag to match edges of texture

The parametric textures are:

Bulge Checker Cloth File Fractal Grid

Mountain Noise Ramp Stencil Water

Solid and Environmental Texture Parameters

The following texture parameters are common to Solid Textures and Environments:

Parameter	Absolute Range	Useful Range	Default
transformation_name			no default.

The following texture parameters are common to Solid Textures, with the exception of sRock, Snow and Leather.

Parameter	Absolute Range	Useful Range	Default	Description
xripples	0, infinity	0, 100	1.0	Fundamental frequencies for noise function
yripples	0, infinity	0, 100	1.0	" "
zripples	0, infinity	0, 100	1.0	" "
level_min	0, infinity	0, 50	0.0	Minimum allowed level of iteration
level_max	0, infinity	0, 50	20.0	Maximum allowed level of iteration
ratio	0, 1	0, 1	0.707	Ratio for fractal noise

Please note that X,Y, and Z refer to the height, width, and depth respectively of the scene as it would appear in the FRONT window, regardless of coordinate system.

The solid textures are: sFile, sCloud, sFractal, sRock, sMarble, Snow, Leather, Granite, Volume, and sWood.

The environment textures are: Ball, Chrome, Cube, Sky, and Sphere.