2011

Ray-traced Shadows
Ray-traced shadows (like other ray-traced effects of reflection and refraction)
are generated by tracing the path of light beams or rays sampled from a light
source. Ray-traced shadows are more accurate than shadow-mapped shadows.
The following example shows that while ray tracing takes longer to process,
it produces more realistic, precise shadows.
Ray-traced shadows have hard edges and accurate outlines; they also transmit
color from transparent and translucent objects. Therefore, shadows of the
frame and mullions of a multi-pane window will render. Because ray-traced
shadows are calculated without a map, you don't have to adjust resolution as
you do for shadow-mapped shadows.
Shadow Modes
You can select one of three shadow mode settings when shadows are turned
on. The shadow mode can be set to Simple, Sort, or Segment.
■ Simple. The renderer calls shadow shaders in a random order. This is the
default mode state for shadows.
■ Sorted. The renderer calls shadow shaders in order, from the object to the
light.
■ Segment. The renderer calls shadow shaders in order along the light ray
from the volume shaders to the segments of the light ray between the
object and the light.
Displaying Shadows
In order for shadows to be cast in a model, lighting must be established. A
light source needs to be added to the scene and you need to specify if that
Use Shadows in Rendering | 2131