Overview
In Using the Displays group of attributes the user can specify what images (or Displays) will be rendered; each display specifies one or several layers of images to output simultaneously from the rendering process. Each can be set to output to a file or a screen window, use a specific Arbitrary Output Variable (AOV), or even contain a subset of the rendered scene. By default, there one display. However, it is possible to add several distinct displays that will all be rendered simultaneously (in a single render pass)be displayed on screen (in a Window) or be saved to a file or both. By default, the Display group of attributes is setup to output only one image layer: the RGBA components representing the main image, also commonly referred to as the Beauty. And it is setup to be outputted to the Maya Render View.
It is possible to add any number of displayslayers, each set to output any AOV that are declared in the shaders.
The Displays group
complementary values to the Beauty image. These are derived from variables computed inside shaders and are commonly called Arbitrary Output Variables (AOVs). Example of layers are: depth values associated to the Beauty image, original color of surfaces (without the effect of the lighting), the specular and diffuse shading components of the Beauty image. These layers can be useful for compositors to have many options while composing the final image. Refer to Display AOVs for further details on supported AOVs.
Layers can not only be generated using different AOVs, they can also be generated from different camera angles. This is very powerful for fast simultaneous multi-camera rendering (for 3D stereo for example). Additionally, each layer can contain a different subset of the objects in the scene. These are more advance options and are described in the Display Advanced Attributes.
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All the layers are rendered simultaneously. Adding many layers do not generally increase rendering time significantly. This is different and not to be confused with the 3Delight for Maya functionality of Render Passes. Those are processed sequentially and can produce totally different output from one pass to another. |
The Displays group
Adding, Removing and Selecting Layers
Among the user interface items inside the Displays group of attributes, there are a few buttons and a popup menu that are useful to add and remove layers and select if they are active or not. Here is a description of their functionalities:
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In 3Delight for Maya, each layer of images is called Display. This is because in RenderMan, the output of the rendering is specified using RiDisplay tokens. In a future release, there will be changes and improvements to the user interface for this group of attributes and the Display labelling will be modified. |
Add Display
Remove Display
Duplicate Display
To add a display,
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click on
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the Add Display button. This will add a pane for that new display. Many displays (i.e. layers) can be added this way. The Remove Display button is presented as a trashcan inside each display pane. Click on it to remove a display.
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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
The attributes for all the displays are presented in panes below the Add Display button. Here is an example of the Display group with three displays.
Render Primary
Specifies
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if the primary display is
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to be rendered. The primary display is always the display at the top of the
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Displays panel and this control is tied to the first display’s
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Active toggle (see below). Generally, the primary display is the Beauty image simply because it is where it is first placed by default. It can be useful to turn this option off when you
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only need to render
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one or more secondary displays (such as when rendering shadow maps). By default, this toggle is on.
Render Secondary
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Specifies if the other displays than the first
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are to be rendered. This toggle will override the per-display
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Active toggle (see below). This control is on by default.
Per Layer Attributes
Each
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pane shows basic attributes for each layer. In each pane there are also additional per-layer attributes located in the Advanced collapsable layout. Refer to the Display Advanced Attributes for a description of these advanced attributes.
Group of attributes for a specific display
A display panel’s first row offers the following attributes:
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Active Toggle
The check box on the left side of the
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text field for the Image Filename specifies if the display is active or not. If it is not active, it will not be rendered
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. Since the first display in the panel is considered the primary display, its
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Active toggle is tied to the Render Primary toggle. For other displays, their
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Active toggles are acknowledged only when Render Secondary is turned on.
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Image Filename
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Specifies the filename for saving the rendered image
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. By default, a
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filename based on the scene name and render pass name is created. See
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for details on how it is possible to construct relative paths and
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paths containing dynamically expanded tokens.
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A Browse for Image File button
Next to the text field for the filename, there are two buttons (shown as icons):
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The second row offers the following attributes:
A Remove Display button
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DeviceAnchor device device
This
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| Display Name | Description |
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| idisplay | The rendered image is sent to i-display |
| maya_render_view | The rendered image is displayed in Maya’s Render View. Note that this display should not be used when rendering to a RIB file since it only works for rendering launched in Maya by 3Delight for Maya. |
| tiff | The AOV is saved in TIFF format. |
| iff | The image/AOV is saved in IFF format. Note that only 8 bits RGB or RGBA images can be output by the IFF display driver. |
| exr | The rendered image/AOV is output in a file in "Open EXR" format. The Open EXR libraries, which are not included in the 3Delight package, must be installed. This display driver only works in 16-bits float or 32-bits float. |
| cineon | The rendered image is output in a file in Cineon format. It is recommended to set the Bit Depth 32 bit float. |
| zfile | The rendered AOV will be a depth map file. It is recommended to set the bit depth to 32 bit float. The AOV in this case should be set to ‘z’. |
| eps | The rendered image is output in a file in Encapsulated PostScript format. |
| bmp | The rendered image is output in a file in BMP format. |
| psd | The rendered image is output in a file in PSD format. |
| radiance | The rendered image is saved in Radiance format. This display driver only works in 32 bits float. |
| null | The rendered image is discarded. |
| shadowmap | The rendered image will be a depth map in TIFF format, suitable to be used as a shadow map. Bit Depth has to be set to 32 bit float and the AOV to 'z'. |
Texture | The rendered image will be a mipmap TIFF, suitable to be used as a texture map without the need of converting it with tdlmake. |
| dsm | The rendered image will be a "Deep Shadow Map". The deep shadow map display driver has several restrictions: the Bit Depth attribute should be set to 32 bit float and the AOV should be set to "rgba". The required Pixel Filter is ‘box’ and the required Filter Width is 1 x 1. |
| jpg | The rendered image is output in a file in JPEG format. |
| pic | The rendered image is output in a file in Softimage’s PIC format. |
| png | The rendered image is output in a file in PNG format. |
AOV
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attribute has to distinct purposes: either to specify to view the image on screen or to specify the image format for saving the image on file. To view the image on your screen, you have two options: you select either "maya_render_view" (to view in the Maya Render View) or "idisplay" (to view in 3Delight i-Display). Alternately, to save the image on file, select between the several formats available. Refer to Image File Formats for a description of each format supported.
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AOV
Specifies which AOV to generate for that display (layer). The most common values are ‘rgba’ or ‘rgb’ for the color image (the Beauty). Clicking on the arrow button next to the AOV text field pops up a menu that lists available predefined output variables. Alternately, you can write here any custom and properly defined 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.
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The predefined AOVs (available through the menu) are explained in the Display AOVs section.
Bit Depth
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Specifies how many bits to use per
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layer component. The available bit depth values are:
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The Custom Bit Depth Dialog
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Advanced Options
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The Advanced group, which is collapsed by default, offers the following attributes:
Alternate Camera
This attribute can be used to specify a different camera than the Render Camera (specified in the Scene Elements group) to be used for this display. This allows simultaneous multi-camera angle or stereoscopic rendering. For best performance, it is recommended to keep as many displays as possible set to <render camera>. For instance, when working with a stereoscopic project that has a "left eye" camera and a "right eye" camera, it is preferable to set the Scene Elements' Render Camera to the "left eye" camera, and alter the value of the display's Alternate Camera only for the ones needed the "right eye" camera (instead of having all displays overriding the render camera with either the "left eye" or the "right eye" camera). By default, the display will use the Render Camera.
Display Subset
This attribute is used to select one or several Maya sets that is used to narrow down what objects will appear in the display. Set selection is made using the 3Delight Set Selector window which is invoked by clicking on the Sets... button. The "Display Subset" option menu specify how the selected sets will be interpreted and has the following values available:
| Option | Description |
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| All Objects | All visible objects will appear in the display, disregarding any sets selec- tion made in the 3Delight Set Selector. This is the default. |
| Objects in selected sets | Only visible objects in the selected Maya sets will appear in the display. |
| Objects not in selected sets | Only visible objects that are not in the selected Maya sets will appear in the display. Put differently, all objects in the selected sets will be excluded from the display. |
Light Category
This attribute specifies a light category (see Category); only the lights of this category will appear in the display. This option requires setting the Render Engine attribute to Path Tracer (see Render Engine).
Gain
Specifies the gain. Each rendered pixel’s color will be multiplied by this value. ‘Gamma’ Specifies the gamma. Each rendered pixel’s color, once affected by "Gain", goes through a power function whose exponent is 1 / "Gamma".
Override Pixel Filter
Each display can have its own filter and filter width values. This toggle is off by default, in which case the display will use the values specified in the Quality section of the render pass. When this toggle is on, these values are overridden with the values specified in the following two attributes: ‘Pixel Filter’ ‘Filter Width’ These two attributes are identical to the "Pixel Filter" and "Pixel Filter Width" in Rendering Quality.
Use Matte Attribute
When this toggle is off, and if the display’s output variable is set to an arbitrary output variable, any matte attribute set on objects will be ignored. This toggle is on by default. Refer to the matte attribute here Visibility.
Exclusive Output
When this toggle is off, and if the display’s output variable is set to an arbitrary output variable, objects that do not output that variable will be black. Turning this option on will make these objects transparent. This toggle is off by default.
Associate Alpha
When this toggle is off, the color of a pixel is divided by the alpha to produce an image with an unassociated alpha channel. By default, this toggle is on.
Compute Alpha
When this attribute is on and the display’s "Output Variable" is an AOV, an alpha channel is added to the AOV. It is computed based on the existence of the output variable for a given object. This toggle is off by default. Usually, when this toggle is on, it is recommended to turn off Associate Alpha.
Edge Detection Options
The Edge Detection subgroup
3Delight can perform outlining on any variable. This can be useful, for example, when doing toon rendering or illustration. An example scene can be found in ‘$DELIGHT/example/maya/outlines’. It is also possible to render shaded wireframes on polygon meshes; see [Polygons Wireframe], page 27.
Enable
This attribute enables edge detection for this particular display. it is set to off by default.
Detected Variables
This attribute specifies on what variables the edge detection (outlining) will run. Several variables can be specified, separated by a coma. For example, setting this attribute to ‘N,z,Oi’ will run edge detection on normals, depth and object contours. By default, this attribute is set to ‘Ci’, which is the color of the light reflected by an object.
Threshold
This attribute controls the sensitivity of the edge detection. The higher the threshold the more sensitive the edge detection is. For example, when detecting variations on ‘z’ (depth), a value of ‘0.1’ means that if there is a gap of ‘0.1’ between two surfaces (in the z direction) then an edge will be generated. This attribute is set to ‘0.1’ by default.
Color
This attribute defines the color of the generated outline. It is set to white by default.
Filter Width
This attribute defines the width of the generated outline. It is set to ‘0.2’ by default. Values between ‘0’ and ‘1’ are allowed, producing very fine outlines. In this case it is recommended to raise the "Pixel Samples" attribute (see [Pixel Samples], page 49) in order to avoid aliasing of the outlines.
Next to this attribute, there is an option menu to determine how this width should be interpreted. The possible values are:
| Pixels | The filter width is a number of pixels. |
| % of Frame Width | The filter width is taken as a percentage of the image resolution in X. |
Depth Based Fadeout
This attribute enables the edge thickness fadeout with depth. It is off by default.
Min Z
Max Z
These two attributes specify the depth range on which the fadeout will be performed. By default, "Min Z" is set to ‘0.0’ and ‘Max Z’ is set to ‘1000.0’.
Min Filter Width
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