MayaMan Help Contents

# MayaMan Extra Output Channels

Some RenderMan renderers allow you to output additional image channels along with the normal RGBA channels. This dialog allows you to select which channels to output, their format and parameters. See the PRMan Application note #24 for more details.

### Output Extra Channels during Preview

This option controls whether the extra output channel images are produced when doing a preview.

### Do Extra Channels Preview With Animal Driver

When enabled, and the Output Extra Channels during Preview option is enabled, the extra output channels will be redirected to the animal display driver and shown on screen (Windows only).

### Output Extra Channels during Render

This option controls whether the extra output channel images are produced when doing a render-single or render-sequence.

### Channels Listing

This listing shows all the extra output channels currently configured to be output at render time. This list is initially empty. You can modify any added channels by typing into the fields of the listing.

Individual channels can be turned on and off with the On column, if a channel is marked as off then the channel will not be output regardless of the state of the Output Extra Channels during xxx checkboxes.

### Default Output Path Uses Channel Name as Subdirectory

When enabled this will cause the output files to be placed in a subdirectory of the main image directory, each subdirectory will bear the name of the channel being output.

### If In Subdir, Roll Channel Name Into Filename

An extension on the subdir naming strategy, in this case the channel name will be rolled in the file name part of the path as well as being used as the directory name, this makes it much easier to see what clip is what when loaded into a compositing package.... this option is defaulted to on.

### Output File Naming Convention

By default each channel will be output to a file name that is synthesized from the normal output file name and the channel name (subject to modification by the two SubDir related toggles mentioned above). This can be overridden by making an entry in the Path column. The value supplied should not attempt to specify frame numbering or extension as mayaman will automatically add them. For example, the __diffuse channel would normally get written to somewhere like `$(PROJECTDIR)/mayaman/images/$(SCENENAME)__diffuse.0001.tif` but you might want it to go into a subdirectory called diffuse but otherwise named like the main image. This would be accomplished with a setting like this: `$(PROJECTDIR)/mayaman/images/diffuse/$(SCENENAME)`.

### General Channel Options

#### Channel

Here you select the channel to output. Select one of the preconfigured channels, or select '<custom>' and type a channel name in the edit field to the right of the channel dropdown box. You can output variables from your RenderMan shaders by declaring them to be 'output' type in the shader and entering their name here.

#### Type

Select the type of the channel being output. This is the type of the input value, not how it will be written out.

#### Dither

The extra output channel images can be dithered, just like the main output image.

#### Driver

Which display driver to use for the channel, if left blank then the main render (not preview) display driver will be used with the following exception.... if the main driver is 'null', 'animal' or 'it' then it will be changed to 'tiff'. If you really do want to use one of those two drivers then they must be specifically selected.

If the driver name is set to '+' then the channel will be rolled into the main output image and all other settings for the channel are pretty much irrelevant. Not all renderers support this (Air does) and not all drivers support this (tiff, openexr and psd do).

#### Filter

The filter to apply to the channel, if left blank then the default is used... ie: the same as the main display.

#### Filter X/Y

The x/y width of the filter for this channel. If the value is 0/0 then the default is used.

### Quantization Channel Options

Here you can enable the quantization of the output channels. Without doing this they will be saved out in floating point format, which most tools cannot read correctly. See the MayaMan Advanced Options dialog for more details on quantization.

### Air Light Channels

To use Air's 5.0 and later's Light Channels you must first add a MayaManLightAttributes node to each light that is to produce output and set it's channel number (in the misc section) to a value between 0 and 9 (inclusive). Then, in the extra output channels dialog, enter a symbolic name for the data channel (ie: key, fill), turn on the 'light' checkbox, enter a channel number in the box next to the light checkbox.

The symbolic name you've given the channel will be used in the synthesis of of the output filename but will be replaced by __lights as required.

Home grown shaders must conform to the __channel and __lights convention outlined in the Air manual.

### Channels that Magic Shaders Produce

The magic shaders produce the following output variables, the suggested quantization and dither settings are a good place to start, more advanced users may wish to output things like __normal unquantized (ie: as floating point data):

Channel | Description | Type | Quantize | Min | Max | Zero | One | Dither | Dither Amount
__shadow | a color representing the amount of shadow at each pixel, computed as the sum of the inverses of the shadows for all lights casting shadows on the surface | Color | on | 0 | 255 | 0 | 255 | on | 0.5
__specular | a color representing the amount of specular at each pixel | Color | on | 0 | 255 | 0 | 255 | on | 0.5
__reflect | a color representing the reflection at each pixel | Color | on | 0 | 255 | 0 | 255 | on | 0.5
__refract | a color representing the refraction at each pixel | Color | on | 0 | 255 | 0 | 255 | on | 0.5
__incandescence | a color representing the incandescence at each pixel | Color | on | 0 | 255 | 0 | 255 | on | 0.5
__ambient | a color representing the ambient light at each pixel | Color | on | 0 | 255 | 0 | 255 | on | 0.5
__diffuse | a color representing the amount of diffuse light at each pixel including shadows | Color | on | 0 | 255 | 0 | 255 | on | 0.5
__diffuse_unshadowed | a color representing the amount of diffuse light at each pixel excluding shadows | Color | on | 0 | 255 | 0 | 255 | on | 0.5
__normal | a normalized forward facing vector in camera space representing surface normal | Normal | on | 0 | 255 | 128 | 255 | on | 0.5
__matteOpacity | the matteOpacity output of the shaders | Float | on | 0 | 255 | 0 | 255 | on | 0.5
__indirect | a color representing the amount of indirect at each pixel | Color | on | 0 | 255 | 0 | 255 | on | 0.5

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