8

Depth of Field with the mental ray Renderer 89
Motion blur added to rendering of a n animated w heel as it
speeds up and rolls forward
To render motion blur with the mental r ay
renderer, you must turn on ray tracing (the Ray
Trace parameter) on the Render Scene dialog >
Renderer panel >
Rendering Algorithms rollout
(page 3–113)
.
The mental ray renderer uses a Shutter parameter
to control motion blur. This simulates the shutter
speed of a camera. At 0.0, there is no motion
blurring.At1.0,themaximumamountofmotion
blurring occurs. Values between zero and one
adjusttheamountofmotionblur.Thecloserto
1.0, the greater the blurring.
Youturnonmotionblurandadjustshutterspeed
on the Render Scene Dialog > Renderer panel >
Camera Effects rollout (page 3–100) .
If you render using
shadow maps (page 3–1105) ,
then by default mental ray applies mot ion blur
totheseaswell. SeetheRenderScenedialog>
Renderer panel >
Shadows & Displacement rollout
(page 3–111)
.
Tip: mental ray motion blur is not recommended
for use with particle systems, as this can increase
rendering time considerably. Use a
Particle MBlur
map (page 2–1486)
instead.
Note: Motion blur with the mental ray renderer
does not always follow curving trajectories.
Increasing the value of M otion Segments can help,
but this works better for rotary motion than for
traveling motion.
Depth of Field with the mental ray
R enderer
Depth of field is a way to enhance the realism of
a rendering by simulating the way a real-world
camera works. With a broad depth of field, all or
nearly all of a scene is in focus. With a narrow
depth of field, only objects within a certain
distance f rom the camera are in focus.
Scene rendered using no depth of field
All apples are equally in focus.
Same scene usin g depth o f field to control focus
The middle apple is clearer than the other two.