User Manual

Table Of Contents
RGBA: This option tells the renderer to produce the Red, Green, Blue, and Alpha color
channels of the image. These channels are required, and they cannot be disabled.
Z: This option enables rendering of the Z-channel. The pixels in the Z-channel contain
a value that represents the distance of each pixel from the camera. Note that the
Z-channel values cannot include anti-aliasing. In pixels where multiple depths overlap,
the frontmost depth value is used for this pixel.
Normal: This option enables rendering of the X, Y, and Z Normals channels. These
three channels contain pixel values that indicate the orientation (direction) of each pixel
in the 3D space. A color channel containing values in a range from [–1,1] is represented
by each axis.
TexCoord: This option enables rendering of the U and V mapping coordinate channels.
The pixels in these channels contain the texture coordinates of the pixel. Although
texture coordinates are processed internally within the 3D system as three-component
UVW, Fusion images store only UV components. These components are mapped into
the Red and Green color channels.
ObjectID: This option enables rendering of the ObjectID channel. Each object in the 3D
environment can be assigned a numeric identifier when it is created. The pixels in this
floating-point image channel contain the values assigned to the objects that produced
the pixel. Empty pixels have an ID of 0, and the channel supports values as high as
65534. Multiple objects can share a single Object ID. This buffer is useful for extracting
mattes based on the shapes of objects in the scene.
MaterialID: This option enables rendering of the Material ID channel. Each material in
the 3D environment can be assigned a numeric identifier when it is created. The pixels
in this floating-point image channel contain the values assigned to the materials that
produced the pixel. Empty pixels have an ID of 0, and the channel supports values as
high as 65534. Multiple materials can share a single Material ID. This buffer is useful for
extracting mattes based on a texturefor example, a mask containing all the pixels that
comprise a brick texture.
Anti-Aliasing
Anti-aliasing can be enabled for each channel through the Channel menu. It produces an output
image with higher quality anti-aliasing by brute force, rendering a much larger image, and then
rescaling it down to the target resolution. Rendering a larger image in the first place, and then
using a Resize node to bring the image to the desired resolution can achieve the exact same
results. Using the supersampling built in to the renderer offers two distinct advantages over
this method.
The rendering is not restricted by memory or image size limitations. For example, consider the
steps to create a float-16 1920 x 1080 image with 16x supersampling. Using the traditional
Resize node would require first rendering the image with a resolution of 30720 x 17280, and
then using a Resize to scale this image back down to 1920 x 1080. Simply producing the image
would require nearly 4 GB of memory. When anti-aliasing is performed on the GPU, the OpenGL
renderer can use tile rendering to significantly reduce memory usage.
The GL renderer can perform the rescaling of the image directly on the GPU more quickly than
the CPU can manage it. Generally, the more GPU memory the graphics card has, the faster the
operation is performed.
Interactively, Fusion skips the anti-aliasing stage unless the HiQ button is selected in the Time
Ruler. Final quality renders always include supersampling, if it is enabled.
Because of hardware limitations, point geometry (particles) and lines (locators) are always
rendered at their original size, independent of supersampling. This means that these elements
are scaled down from their original sizes, and likely appear much thinner than expected.
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