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Render group > Motion Blur

This Motion Blur group lets you add motion blur to particles. With real cameras, the shutter stays open for a brief time, during which a fast-moving object shifts slightly during the frame capture, creating a blur in the motion’s direction. Motion Blur mimics this effect.

Technical note about render time:

Note that Motion Blur produces a lot of particles, which can make your project quite memory intensive. This is because Form’s Motion Blur is somewhat different from motion blur effects in other software.

Most applications and plug-ins blend some frames that are time offset to produce a blurred frame. In Form, additional particles insert into the particle list before rendering. This method means that depth cueing in the blurred frame is correct. It also means that per-particle transfer modes are applied for each blur level, and that produces a lot of extra particles.

Motion Blur

You can tell Motion Blur to be Off, On, or to use the host application's motion blur (Comp Settings).

• Off: Turns Motion Blur off.
• On: Turns Motion Blur on.
• Comp Settings: This default setting turns Motion Blur on and grays out the Shutter Angle and Shutter Phase controls. This is because the Shutter Angle and Shutter Phase values from the After Effects composition are used. These values are in After Effects' Composition > Composition Settings > Advanced menu. To activate Motion Blur with Comp Settings, the comp Motion Blur switch and the layer Motion Blur switch must be enabled.

The Motion Blur menu (left) and After Effects switches that tie into the Comp Settings option (right).

Shutter Angle: Active for the Motion Blur > On option. Shutter Angle sets how long the virtual camera shutter stays open. This controls the “streak length” or “blur length” of particles.

A value of 0 means no motion blur. Low values set a short streak. The default value of 180 simulates a half-second of motion information being recorded on film. High values set a longer particle streak. A value of 720 (the maximum) simulates two seconds of blurring.

Shutter Phase: Active for the Motion Blur > On option. Shutter Phase offsets the point in time when the virtual camera shutter opens.

A value of 0 means the shutter is synchronized to the current frame. A negative value causes motion that occurs before the current frame to be recorded. A positive value causes motion that occurs after the current frame to be recorded. To create motion streaks with the current frame in focus, use a Shutter Phase negative value equal to the Shutter Angle.

Levels: Defines how many levels of sampling should be used in the motion blur calculation. A faster motion and higher shutter angle will require more levels to produce a smooth blur. Higher values mean more samples, which will increase rendering time significantly.