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Default Scanline Renderer Rollout 43
dialog for that object. Image motion blur blurs
the object by c reating a smearing effect rather
than multiple images. It takes camera movement
into account. Image motion blur is applied after
scanline rendering is complete.
The coin on the right has Image Motion Blur applied
You can’t put image motion bl ur on objects that
change their topology.
Tip: When blurred objects overlap, sometimes
blurring doesn’t work correctly and there are gaps
in the rendering. Because image motion blur
is applied after rendering, it can’t account for
object overlap. To fix this problem, render each
blurred object separately, to a different layer, and
then composite the two layers using the Alpha
Compositor in Video Post.
Note: Imagemotionblurdoesn’tworkforNURBS
objects that are animated so their tessellation
(surface approximation (page 1–1239))changes
over time. This happens when sub-objects are
animated independently of the top-level NURBS
model (page 3–980). Nor does image motion blur
work on any of the following:
• Anything with an Optimize.
• Any primitive with animated segments.
• MeshSmooth of any type with a "Smoothness"
value (under iterations) other t han 1.
• MeshSmooth on polygons with Keep Faces
Convex on.
• Anyth ing with Displacement Material.
In general, if you have objects with changing
topolog y, use scene or object motion blur rather
than image motion blur.
Apply —Turns image motion blur on or off globally
for the entire scene. Any objects that have their
Image Motion Blur property set are rendered with
motion blur.
Duration—Specifies how long the "virtual shutter"
is open. When this is set to 1.0 , the vir tual shutter
is open for the entire duration b etween one frame
and the next. The hi gher the value, the greater the
motion blur effect.
Apply to E nvironment M ap—When set, image
motion blur is applied to the env ironment map
as well as to the objects in the scene. The effect is
noticeable when the camera orbits.
The environment map should use Environment
mapping: Spherical, Cylindrical, or Shrink-Wrap.
The image motion blur effect doesn’t work with
Screen-mapp ed env ironments.
Transparency—When on, image motion blur works
correctly with transparent objects that overlap .
Applying image motion blur to transparent objects
can increase rendering time. Default=off.
Auto Reflect/Refract Maps group
Rendering I terations—Sets the number of
inter-object reflections in non-flat automatic
reflection maps. Although increasing this value
can sometimes enhance image quality, it also
increases rendering ti me for reflections.
Color Range Limiting group
Color Range Limiting allows you handle
over-brightness by toggling between either
Clamping or Scaling color components (RGB)