Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 209

Note: Previous versions of After Effects included an effect called Motion Blur. That effect is now named Directional Blur,
to avoid confusion with motion blur applied to layers.
• Click the Motion Blur
• Select the layer and choose Layer > Switches > Motion Blur.
The number of samples that After Effects uses to calculate motion blur adapts for each layer, depending on the
motion of that layer. This provides high-quality motion blur without unnecessarily sampling the motion of a slow-
moving layer as frequently as that of a fast-moving layer. High sampling rates decrease rendering performance.
See also
"Apply frame blending to a layer" on page 226
"Apply motion blur to a mask" on page 267
"Work with render settings" on page 591
Motion blur settings in the Advanced tab of Composition Settings
The minimum number of samples. This is the number of samples used for frames for which
Samples Per Frame
After Effects is not able to determine an adaptive sampling rate based on layer motion. This sample rate is used for
3D layers and shape layers.
The maximum number of samples.
Adaptive Sample Limit
The shutter angle is measured in degrees, simulating the exposure allowed by a rotating shutter. The
Shutter Angle
shutter angle uses the footage frame rate to determine the simulated exposure, which affects the amount of motion
blur. For example, entering 90˚ (25% of 360˚) for 24-fps footage creates an effective exposure of 1/96 of a second (25%
of 1/24 of a second). Entering 1˚ applies almost no motion blur, and entering 720˚ applies a large amount of blur.
The shutter phase is also measured in degrees. It defines an offset that determines when the shutter
Shutter Phase
opens relative to the beginning of a frame. Adjusting this value can help if an object with motion blur applied appears
to lag behind the position of the object without motion blur applied.
A Shutter Phase value that is -1/2 of the Shutter Angle value is best for a layer that is composited on top of another
using motion tracking data. (For example, Shutter Phase = -90, Shutter Angle = 180.) This setting combination
causes a blur that is centered on the original object.
Smooth motion and velocity
Smooth motion paths, value curves, and velocity curves to eliminate bumpiness or excess keyframes using The
Smoother, which adds keyframes or removes unnecessary keyframes. You can also use the
accomplish this.
Although you can smooth a curve for any property, The Smoother is most useful when applied to curves that have
been automatically generated by Motion Sketch, where you may have excess keyframes. Applying The Smoother to
keyframes that have been set manually may result in unexpected changes to the curve.
Note: To avoid the need to use The Smoother on a path generated by Motion Sketch, set the Smoothing option in the
Motion Sketch panel before sketching the motion path.
When you apply The Smoother to properties that change spatially (such as Position), you can smooth only the spatial
curve (the curve defined by the motion). When you apply The Smoother to properties that change only in time (such
as Opacity), you can smooth only the value and velocity curves (the curve defined by the value or the velocity).
layer switch for the layer in the Timeline panel.
AFTER EFFECTS CS3
User Guide
expression to
smooth
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