However, the render takes significantly longer to calculate. Raytraced shadows are always
hard edged, yet they are realistic for transparent and translucent objects. Figure 10.50
shows a pair of chess pieces rendered with a plane casting a shadow over them. The plane
has a checker mapped to its opacity, so it has alternating transparent and opaque squares
defining the checkerboard. On the left side of the image in Figure 10.71, the light is casting
Shadow Map shadows, while on the right the light is casting Raytraced shadows.
Figure 10.70
Soft-edge shadows
Size = 1024 Size = 4096
Figure 10.69
The Shadow Map
size affects the
shadow detail.
lighting the red rocket ?– 491
Use Raytraced shadows when you need highly accurate shadows or when Shadow Map
resolutions are just not high enough to get you the crisp edges you need. You can also use
Raytraced shadows to cast shadows from wireframe rendered objects.
The Raytraced Shadow rollout, shown here, controls the shadow. The Ray Bias parameter
is the same as the Shadow Map Bias in that it controls how far from the casting object
the shadow is cast.
Creating Soft Shadows Due to Distance
The only way you will be able to create a natural shadow that softens the farther it gets from
the casting object is to use Area shadows.
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