8

Shadows and Displacement Rollout (mental ray Renderer) 111
• Stop—Specifies the maximu m leng th, in
3ds Max units, of a light ray. If the ray reaches
this limit without encountering a surface,
then the environment is used for shading.
Default=0.0.
Shadows and Displacement
Rollout (mental ray Renderer)
Rendering menu > Render > Render Scene dialog >
Renderer pa nel > S hadows & Displacemen t rollout
Main toolbar > Render Scene > Render Scene dialog >
Renderer pa nel > S hadows & Displacemen t rollout
Note: The Renderer panel appears only when the mental
ray renderer is the currently active renderer.
The controls in this rollout affect shadows (page
3–88)
and displacement (page 3–95) .
Note: You can disable d isplacement globally by
turning off Displacement in the Options group on
the
Common Parameters rollout (page 3–27) .
Inter face
Shadows group
Enable—When on, the mental ray renderer renders
shadows. When off, no shadows are rendered.
Default=on.
When Enable is off, the other shadow controls are
unavailable.
Mode—The shadow mode can be Simple, Sort, or
Segments. Default=Simple.
•
Simple—Causes the mental ray renderer to call
shadow shaders in a random order.
•
Sort—Causes the mental ray renderer to call
shadow shaders in order, from the object to
the light. Sor t applies to third-party, external
shadow
shaders (page 3–1103) .
•
Segments—Causes the menta l ray renderer to
cal l shadow shaders in order along the light ray
fromthevolumeshaderstothesegmentsofthe
light ray between the object and the light.
Tip: Choose Simple for regular shadows, Segments
for volume shadows.
Shadow Maps group
These cont rols specify a
shadow map (page
3–1105)
used to render shadows. When you
specify a shadow map file, the mental ray renderer
uses the shadow map instead of ray-traced
shadows.
To stop using a shadow map and use ray-traced
shadows, delete the map’s name from the file name
field.
Enable—When on, the mental ray renderer renders
shadow-mapped shadows. When off, all shadows
are ray-traced. Default=on.
When Enabled is off, the other controls in this
group are unavailable.
If shadows are enabled but shadow maps are not
enabled, then shadows for all lights are generated
using the mental ray ray-tracing algorithm. If
shadow maps are enabled, then shadow generation
is based on each lig ht’s choice of shadow generator:
•
mental ray Shadow M ap—Shadows are
generated using the mental ray shadow-map
algorithm.