Endless POVabilities

The Fifth Lesson - Fun With Images -- Continued

Part 5 - Transparency (Filter/Transmit) Maps

Finally, another use for images is to create masks that indicate how translucent different portions of an object are to be. For example, to create a stained glass window you might use a transparency map of two colours only to indicate the leading and glass (areas of no and some transparency), in concert with an image map of many colours that indicates the shades of the different glass pieces and the leading between. Or you could make an intricate paper cutout by drawing the desired pattern in black and white and then applying it over a low-relief height field to create the necessary cut-outs.

Tissue Paper Snowflake

object {
height_field {
gif "paper.gif"
}
texture {
pigment {
image_map {
gif "flake.gif"
transmit 0,1
transmit 1,.15
}
rotate x*90
}
}
translate <-.5*foot,0,-.5*foot>
scale <6*inches,.5*inches,6*inches>
rotate x*-30
rotate y*-15
translate <3*inches,5*inches,0>
}

In this lesson we've really only skimmed the surface of what can be done with images; many of the most interesting effects can be achieved by combining different image uses, as was seen in the combination of the height_field with an image_map (for the miniature mountain) and a filter/transmit map (for the snowflake). Have fun seeing what combinations you can come up with to solve different problems and create different objects!

The Next Lesson

In the next lesson, we'll take a look at creating a simple animation using POV's "clock" feature.