Creative Effects > Compositor and Optics >
Accessing the Compositor

The Compositor is accessed from the Effects menu. To access the Compositor, you must select a front clip, a back clip, and a matte clip.

To access the Compositor:

1. In the Main menu, click Effects.
2. In the Effects menu, click Compositor.
3. Select the front, back, and matte clips.
4. Select the destination.

   The Compositor controls are described as follows.

   Crop box
     Turns cropping on or off, or allows for an automatic crop. See Cropping the Front Clip.
   Front clip box
     Edits the front clip's visibility.

   Select: | To:
   --- | ---
   Front On | Display the front clip.
   Front Off | Hide the front clip.
   Front Lock | Lock the front clip at the current frame in the timebar.

   Back clip box
     Edits the back clip's visibility.

   Select: | To:
   --- | ---
   Back On | Display the back clip.
   Back Off | Hide the back clip.
   Back Lock | Lock the back clip at the current frame in the timebar.

   Matte clip box
     Edits the matte clip's visibility.

   Select: | To:
   --- | ---
   Matte On | Display the matte clip.
   Matte Off | Hide the matte clip.
   Matte Invert | Invert a matte. Black areas will be made white, and white areas willbecome black.

   Colour Corrector controls
     Allows you to colour correct the front, back, or matte clip. See Colour Correcting Clips.
   Stabilizer controls
     Accesses the stabilizer, and applies translation, rotation, and scaling settings to the composition. See Tracking Clips.
   Motion Path settings
     Sets motion paths for the front clip and camera. See Creating Motion Paths.
   Shadow button
     Places a shadow behind the front clip. See Adding a Shadow to the Front Clip.
   Texture button
     Enables hardware texture mapping.
   Anti-Aliasing and Softness fields
     Controls the level of anti-aliasing. Increasing the number of samples increases the degree of anti-aliasing but also increases the processing time. Adjust the softness to affect the degree of anti-aliasing.

   The jagged lines that often occur along the edges of diagonal or curved lines when processing high-frequency images such as text are the result of aliasing. Aliasing is caused by insufficient spatial sampling of the image. The process of reducing or removing the effects of aliasing by increasing the sampling rate is called anti-aliasing.

   NoteAlthough the cleanest images are obtained when the softness value is set to 1 or 2, higher softness values can also be used for creative effects. The best results are obtained when the softness value is set as indicated in the following table.

   Anti-aliasing | Softness
   --- | ---
   1 | No anti-aliasing occurs and the Softness value has no effect on the image
   2 | 1
   3 | 2
   4 | 2

   Resolution field
     Sets the resolution of image proxies while you work with a layer and play clips in the Compositor. A lower value requires more processing time to generate proxies.
   NoteWhen hardware texture mapping is enabled (Texture button), the value in the Resolution field no longer applies because the hardware controls resolution during interaction and playback.
   Motion Update button
     Updates properties such as position, rotation, and colour in the scene. This button is enabled by default.

   When disabled, animated objects do not move, but keep the position of their current value. Disable Motion Update when you want to copy keyframe values from one frame to another.

   Play Lock button
     Updates the animation settings according to the frame or timebar position as you move through the clip while keeping it locked at the current frame.
   Channel Snap button and Snap field
     Snap keyframe values in the animation curve window. When you move a keyframe in this window, it is automatically aligned to the snap grid.

   The grid size is set to one unit along the X (horizontal) and Y (vertical) axes. To change the grid size along the Y-axis, change the value in the Y Snap field. You cannot change the grid size along the X-axis.

   Blending box
     Defines the blending mode. The Blend option uses both the front and back luminance curves of the matte clip. The Add option uses only the front luminance curve. Select Add to eliminate the black fringe created when using a front clip with a black background.