Datasheet

Scanline and Raytraced Rendering  31
To create a generic noise pattern, you can combine photos of real-world surfaces. Rusty
metal, stucco, dirty concrete, and similar surfaces often contain interesting patterns. In fact,
if you layer several different photos in Photoshop and adjust each layer’s Opacity, you can
generate a more complex result. For example, if you stack three different rusty metal photos
and reduce each layer’s Opacity, an interesting pattern forms (see Figure 1.37). To convert
the result to grayscale, choose Layer

Flatten Image and Image

Adjustments

Desaturate.
To adjust the overall contrast, apply Image

Adjustments

Brightness/Contrast or Image

Adjustments

Curves.
Scanline and Raytraced Rendering
By default, the Maya Software renderer operates in a scanline mode. The scanline process
operates with these basic steps:
Surfaces visible to the rendering camera are noted. Occlusion of one surface by another •
is taken into account.
Polygon faces of the visible surfaces are projected into 2D screen space. The faces are •
processed in scanline order. A scanline is a row of pixels within a render. (Technically
speaking, a pixel is a sample point that carries an x, y coordinate and a color value;
for an image to be stored in a digital system, it must be broken down into a discrete
number of pixels.) Hence, a 1280×720 render has 720 scanlines (with each scanline
possessing 1280 pixels).
Figure 1.37
Three photo bit-
maps of rusty metal
are placed on three
different layers in
Photoshop. The top
and middle layers
are given reduced
Opacity values, lead-
ing to a more com-
plex result after the
layers are flattened
and desaturated.
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