Adobe After Effects CS4 - Manual (Page 437)

431 USING AFTER EFFECTS CS4
Effects and animation presets
Last updated 12/21/2009
The ProEXR package from the fnord software website also includes the ProEXR Comp Creator plug-in. This plug-in
can create a layer from each of the channels of an OpenEXR file. For example, the layers can represent the output from
a set of render passes from a 3D application.
ProEXR plug-ins, IDentifier and EXtractoR
The EXtractoR and IDentifier plug-ins from fnord software are included with After Effects to provide access to
multiple layers and channels of OpenEXR files.
Documentation for fnord ProEXR plug-ins is available in a PDF document on the fnord software website , which
includes links to a sample multi-channel EXR file and an After Effects project that uses it. The instructions in the fnord
document regarding the removal of the OpenEXR plug-ins don’t apply to After Effects CS4.
3D Channel Extract effect
The 3D Channel Extract effect makes auxiliary channels visible as either grayscale or multichannel color images. You
can then use the resulting layer as a control layer for other effects. For example, extract the depth information in a 3D
channel image file and then use it as an influence map in the Particle Playground effect, or extract values from the
unclamped RGB channel to produce a matte that generates glowing highlights.
To display 3D channel values for a pixel in the Info panel, apply the 3D Channel Extract effect, choose the channel
from the 3D Channel menu in the Effect Controls panel, and then click the pixel in the Composition panel or Layer
panel using the Selection tool.
This effect works with 8-bpc color.
Original (left), with 3D Channel Extract applied using Texture UV (right)
Much of the following information is based on information provided by Lutz Albrecht, who also provides a two-
part document on the
Adobe website about integrating 3D applications with After Effects:
White Point, Black Point The value that is mapped to white or black.
3D Channel The channel to extract from the 3D image:
• Z-Depth Represents the distance of a given shaded pixel from the camera. White represents the greatest distance;
black pixels are closest to the camera. Effects such as the Lens Blur effect can use this information to generate depth-
of-field effects. When you apply the channel directly as a luma matte, you get fog. This channel is anti-aliased.
Note: For best results, match the White Point and Black Point settings of the effect with the near and far settings of your
camera in the 3D application that generated the 3D image.
• Object ID Each object can be assigned a separate ID value in the 3D application. You can use a map generated using
this channel to selectively apply effects to certain objects in a 3D scene—for example, to apply selective color
adjustments. This channel is not anti-aliased.
• Texture UV This channel contains the mapping coordinates of the textures of your object, mapped to the red and
green channels. This channel is not anti-aliased.