Using OpenGL interactive previewing

OpenGL is an interactive preview option that provides fast screen previewing of a composition without degrading resolution. For example, the display resolution is the same high level regardless of whether you use OpenGL to preview three layers or 20 layers, because OpenGL uses the memory and graphics processing capabilities on the installed OpenGL hardware. OpenGL is automatically activated when you manipulate layers in the Composition window or the Timeline window by using the mouse.

After Effects requires OpenGL 1.1 or later. After Effects detects OpenGL hardware if it is installed and sets the default preview to OpenGL. OpenGL hardware supports layers up to 2000 x 2000 pixels. For larger layers, After Effects downsamples the resolution of the layer to make it fit the size limitation. Using complex effects can slow down the OpenGL preview. If the preview is too slow, turn off OpenGL and use another preview option.

OpenGL works with both still images and moving images. If a layer contains a movie or moving image, OpenGL can either use each frame from the movie or moving image to create the preview, or it can use a single, designated frame of the layer as a proxy to further enhance the speed of previews.

The Dynamic Preview button turns green when OpenGL is engaged. OpenGL previewing is faster and smoother than Adaptive Resolution previewing.

OpenGL supports most of the basic After Effects features, including transformations, 3D layers, lights, adjustment lights, masks, alpha channel track mattes, and Stained Glass. OpenGL supports only the Normal blending mode.

When OpenGL does not support a feature, it simply creates a preview without using that feature. For example, if you have a layer that uses an Add blending mode, OpenGL previews the layers using the Normal blending mode instead. Or if your layers contain shadows and your OpenGL hardware does not support them, the preview will not contain shadows. However, when you release the mouse and return from OpenGL preview, any unsupported features are rendered and appear again.

Shadow support in After Effects is dependent on the OpenGL hardware; contact the hardware manufacturer for details. For information regarding specific OpenGL hardware, see the After Effects section on the Adobe Web site at www.adobe.com/aftereffects.

To turn on OpenGL interactive previewing:

1. Choose Edit > Preferences > Previews (Windows) or After Effects > Preferences > Previews (Mac OS).
2. Select OpenGL Hardware With Moving Textures or OpenGL Hardware With Static Textures.
3. To view the hardware information, including hardware supported features, click Info.

Note: Adobe recommends leaving your video card's Advanced settings at their default.

4. Enter a value for Texture Memory (Windows only) of no more than 80% of the installed Video Ram (VRAM) on your display card. (On Mac OS, After Effects queries the display card directly to determine the optimal value.)

To use OpenGL preview:

1. In the Timeline window, make sure that the video switch is selected for the layers you want to preview.
2. Click the Dynamic Preview button and choose an OpenGL option from the pop-up menu that appears:
• Choose OpenGL with Moving Textures to preview each frame of the layer.
• Choose OpenGL with Static Textures to preview using a proxy frame. After Effects uses the first frame encountered during previewing as the proxy frame.
3. Do one of the following:
• Drag a layer around the Composition window.
• Drag an underlined, motion-related property value, such as rotation or scale, in the Timeline window.
• Scrub the current-time indicator in the Timeline window.