8

mental ray Concepts 87
This is equivalent to the preference, Open Me ssage
Window On Error .
Cle ar—Click to clear all messages from the
messages area.
menta l r ay Con cepts
Thesetopicsdescribewhatthementalrayrenderer
can do, and explain how it accomplishes these
effects. For more technical detail about mental
ray capabilities, see the mental ray m anual,
Programming mental ray, and Rendering with
mental ray,
book 1, by Thomas Driemeyer (New
York: Springer Verlag , 1999).
See also
Ray-Traced Reflect ions and Refractions with the
mental ray Renderer (page 3–87)
Shadows with the mental r ay Renderer (page 3–88)
Motion Blur with the mental ray Renderer (page
3–88)
Depth of Field with the mental ray Renderer (page
3–89)
Caustic Lighting Effects (page 3–91)
Global Illumination with the mental ray Renderer
(page 3–92)
mental ray Volume Shading (page 3–93)
mental ray Displacement (page 3–95)
mental ray Contour Shading (page 3–95)
Ray-Traced Reflections and
R efr actions wit h the mental r ay
R enderer
The mental ray renderer can generate reflections
and refractions by ray tracing. Ray tracing traces
the p ath of rays sampled from the light source.
Reflections and refractions generated this way are
physically accurate.
Ray-traced reflections and Refractions
To reduce the time required to generate reflections
andshadows,raysarelimitedby
trace depth .
Trace depth limits the number of times a ray can
be reflected, refracted, or both.
You can turn off ray t racing. In this case, the
mental ray renderer uses scanline rendering
only. Turning off ray tracing makes the controls
for all the effects that are specific to mental r ay
unavailable in the Renderer’s rollouts.
Ray tracing uses one of two
ray-trace acceleration
methods (page 3–1094)
.
You enable ray tracing and set trace depth in
the Render Scene dialog > Renderer panel >
Rendering Algorithms rollout (p age 3–113) .