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42 Chapter 17: Rendering
Sampler drop-down list—
Lets you choose which
supersampling method to apply. Default=Max 2.5
Star.
The options for a supersampling method are the
same as those that appear on t he SuperSampling
rollout (page 2–1459) in the Material Editor. Some
methods offer expanded options that let you better
control the qual ity of the supersampling and the
number of samples taken during rendering.
Object M otion Blur group
You determine which objects have object motion
blur (page 3–981) applied to them by setting Object
in the Motion Blur gro up of the Properties dialog
for that object. Object motion blur blurs the object
by creating multiple "time-slice" images of the
object for each frame. It t akes camera movement
into account. Object motion blur is applied during
thescanlinerenderingprocess.
Apply—Turnsobjectmotionbluronoroffglobally
for the entire scene. Any objects that have their
Object Motion Blur propert y set are rendered with
motion blur.
Durati on—D eter mines how long the "virtual
shutter" is open. When this is set to 1.0, the virtual
shutterisopenfortheentiredurationbetweenone
frameandthenext.Longervaluesproducemore
exaggerated effects.
The effect of changing duration.
Samples—DetermineshowmanyDuration
Subdivision copies are sampled. The maximum
setting is 32.
WhenSamplesislessthanDuration,random
sampling within the duration occurs (which is why
there m ight be a slight granular look to the motion
blur). For example, if Duration Subdivision=12
and Samples=8, there are eig ht random samples
out of 12 possible copies within each frame.
When Samples=Duration, there is no randomness
(and if both numbers are at their maximum value
(32),yougetadenseresult(whichcostsbetween
3–4 times the normal rendering t ime for that
specific object).
If you want to obtain a smooth blur effect, use the
maximum settings of 32/32. If you w ant to cut
dow n rendering time, values of 12/12 will give you
much smoother results than 16/12.
Because sampling happens within the duration,
theDurationvaluealwayshastobelessthanor
equal to Samples.
Duration S ubdivisions—Determines how m any
copies of each object are rendered within the
Durat ion.
Left: Same value for S amples and S ubdivisions.
Right: Samples value is less than Subdivisions.
Image Motion B lur group
You determine wh ich objects have image motion
blur (page 3–955) applied to them by setting
Image in the Motion Blur group of the Properties