Overview
In this section users can specify what AOV images (or Displays) will be output by the renderer and to what file or frame bufferrendered; each display can be set to be output to a file or a frame buffer, use a specific Arbitrary Output Variable (AOV), or even contain a subset of the rendered scene. By default, a render pass is created with one display. However, it is possible to create several distinct displays in a single render pass; all displays are rendered simultaneously.
It is allowed to add any number of additional display and output any AOV (Arbitrary Output Variable) AOVs that are declared in the shaders.
Each display is shown in its own panel. To add a display, either click on the Add Display button, or select Add Display in the contextual popup menu that appears when right-clicking almost everywhere in the Displays section. This menu also offers options to expand or collapse all display panels at once. To remove a display, click on its Remove Display button, which appears as a trashcan. To duplicate a display, right-click anywhere above the display to duplicate and select Duplicate Display menu option.
At the top of the Displays section are a few general controls, followed by a list of per-display panels. The general controls are:
Add Display
Clicking this button will add a new display attribute group at the bottom of the displays panel.
Render Primary Display
Controls if the primary display is going to be rendered. The primary display is always the display at the top of the displays panel and this control is tied to the first display’s Render toggle. It can be useful to turn this option off when you need only need to render a secondary display or shadow maps. By default, this toggle is on.
Render Secondary Displays
Specifies if the other displays than the first one are rendered. This toggle will override the per-display Render toggle. This control is on by default.
Each display has its own panel showing the basic display parameters on two rows. The remaining display attributes are located in the Advanced section. A display panel’s first row offers the following attribute:
A Render toggle
Controls The check box on the left side of the image filename controls if the display will be rendered or not. Since the first display in the panel is considered the primary display, its Render toggle is tied to the Render Primary toggle. For other displays, their Render toggle is acknowledged only when Render Secondary is turned on.
An Image Filename
This control specifies the file name of the rendered image. When using a framebuffer display driver, this specifies a window title. By default, a file name based on the scene name and render pass name is created. See Section 5.5.4 [File Path Expressions],page 124 for details on how it is possible to construct relative paths and / or paths containing dynamically expanded tokens.
A Browse for Image File button
This button, drawn as a folder, brings up a file browser to specify an image filename.
A View Image button
This button, drawn as a magnifying glass, will open the display’s image file in a viewing application. See Section 3.17 [The Preferences Window], page 93 for details on how to specify which application should be launched.
The second row offers the following attributes:
A Remove Display button
This button, drawn as a trashcan, removes the display from the render pass.
Device
This options specified the type of the display driver, which is where your rendered image will go. The following display drivers are available:
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AOV
Indicates what variable will be output during this render. The most common values are ‘rgba’ or ‘rgb’ for RGBA and RGB outputs respectively. You can specify here any predefined output variable or arbitrary output variables that your shaders are using. Inline declarations of arbitrary output variables are allowed, meaning that it is permitted to preceded a variable name with its type to declare it and specify it for the display mode all at once. Right-clicking on the text field brings up a popup menu that lists available predefined output variables. The available values that are relevant regardless of the shaders assigned of to scene elements are:
| AOV | Description |
|---|---|
| user specified | This item is selected when a custom variable name is typed in the text field. |
| z [depth] | For a given pixel, this variable outputs the distance between the camera and the object visible at this pixel. Bit depth should de set to 32 bits. |
| rgb [color] | This variable outputs the color information of the rendered image. |
| ‘a [alpha channel]’ | This variable outputs the transparency information of the rendered image. |
‘Oi [3-channel alpha]’ | This variable outputs the R, G and B transparency information of the rendered image. |
‘rgba [color + alpha]’ |
]’ | This |
‘z [depth]’
‘rgb [color]’
Thisvariable outputs the color and transparency information of the |
rendered image. This is also called a beauty render pass. This is the default. |
The following AOVs are defined for scene elements shaded using Maya’s Hypershade. Note that any AOV whose name contains "no shadow" involves extra shading computation and will make the scene longer to render. The available AOVs are:
‘ambient’ ‘diffuse’
‘specular’
This variable outputs the ambient shading component of the rendered image, producing an ambient render pass RGB image.
This variable outputs the diffuse shading component of the rendered im- age, producing a RGB image similar to a Maya Render Layer configured to output a diffuse render pass.
This variable outputs the specular shading component of the rendered image, producing a RGB image similar to a Maya Render Layer configured to output a specular render pass.
‘reflection’
This variable outputs the reflection shading component of the rendered image, producing a reflection render pass RGB image.
‘refraction’
This variable outputs the refraction shading component of the rendered image, producing a refraction render pass RGB image.
‘shadow’
This variable outputs the shadow intensity in the alpa component of a RGBA image, in a similar fashion to a Maya Render Layer configured to output a shadow render pass. Note that in addition to objects being shaded with Maya’s Hypershade, the light sources must also be shaded with Maya’s Hypershade for this output variable to work properly (put differently, the light must not have a RenderMan shader attached to it).
‘incandescence’
This variable outputs the incandescence shading component of the ren- dered image, producing a incandescence render pass RGB image.
‘translucence’
This variable outputs the translucence shading component of the rendered image, producing a translucence render pass RGB image.
‘diffuse no shadow’
This variable outputs the diffuse color shading component of the rendered image, unattenuated by any shadows. The result is identical to what is produced by the ‘diffuse’ AOV when light sources do not cast any shadows.
‘diffuse intensity’
This variable outputs a grayscale image representing the intensity of the diffuse shading component.
‘diffuse intensity no shadow’
This variable outputs a grayscale image representing the intensity of the diffuse shading component without any attenuation made by shadows. If there are no shadow-casting light sources, the result is identical to the ‘diffuse intensity’ AOV.
‘key lights diffuse intensity’
The output of this AOV is similar to the ‘diffuse intensity’ AOV, but will only take into account light sources that have a ‘key light’ attribute set to true. Refer to the [key light attribute], page 41.
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