User Manual

Table Of Contents
might exist in an OpenEXR. In most cases, the channel has a custom name that can be used to
map the extra channel to one of the channels recognized by Fusion.
SoftImage PIC (*.PIC, *.ZPIC, and *.Z)
The PIC image format (used by SoftImage) is an older image format that can contain Z-Depth
data in a separate file marked by the ZPIC file extension. These files must be located in the
same directory as the RGBA PIC files and must use the same names. Fusion automatically
detects the presence of the additional information and loads the ZPIC images along with the
PIC images.
Wavefront RLA (*.RLA), 3ds Max RLA (*.RLA), and RPF (*.RPF)
This is an older image format capable of containing any of the image channels mentioned
above. All channels are contained within one file, including RGBA, as well as the auxiliary
channels. These files are identified by the RLA or RPF file extension. Not all RLA or RPF files
contain auxiliary channel information, but most do. RPF files have the additional capability of
storing multiple samples per pixel, allowing different layers of the image to be loaded for very
complex depth composites.
Fusion RAW (*.RAW)
Fusion’s RAW format is able to contain all the auxiliary channels as well as other metadata used
within Fusion.
Creating Auxiliary Channels in Fusion
The following nodes create auxiliary channels:
Renderer 3D: Creates these channels in the same way as any other 3D application
would, and you have the option of outputting every one of the auxiliary data channels
that Fusion supports.
Optical Flow: Generates Vector and Back Vector channels by analyzing pixels over
consecutive frames to determine likely movements of features in the image.
Disparity: Generates Disparity channels by comparing stereoscopic image pairs.
Auxiliary Channels Explained
Fusion is capable of using auxiliary channels to perform depth-based compositing, to create
masks and mattes based on Object or Material IDs, and for texture replacements. Tools that
work with auxiliary channel information have been specifically developed to work with this data.
Z-Depth
Each pixel in a Z-Depth channel contains a value that represents the relative depth of that pixel
in the scene. In the case of overlapping objects in a model, most 3D applications take the depth
value from the object closest to the camera when two objects are present within the same pixel
since the closest object typically obscures the farther object.
When present, Z-depth can be used to perform depth merging using the Merge node or to
control simulated depth-of-field blurring using the Depth Blur node.
Chapter – 69 Understanding Image Channels 1399