POV-Ray Tips: Materials, Textures, and Finishes

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POV-Ray Tips, Tricks, and Techniques	Fading Pigments?


Martin Magnusson wonders:		I'd like to have a marble pigment that is almost transparent near the centre of my object and less transparent near the edges. How do I go about that?
Charles Fusner succinctly explains:		For this, you need a pigment map. It's an extension to POV-Ray that's like a color map, except with whole pigments. So for example, supposing you predeclared your marble texture as "Marble1"... `pigment {` `gradient x` `pigment_map {` `[ 0 Marble1 transmit 0 ]` `[ .5 Marble1 transmit .75 ]` `// or whatever max transparency` `// you had in mind...` `[ 1 Marble1 transmit 0 ]` `}` `}` Just as is, it will need to be scaled/translated to fit precisely once across your object (however big it is), but you see the idea. The pigment is the same pigment, only solid at both ends of the map, and transparent in the center.