Using the Image Layers group of attributes the user specifies one or several layers of images to output simultaneously from the rendering process. By default, the Image Layers 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. It is possible to add any number of layers, each set to output any complementary information to the Beauty image, such as: Such layers can be useful for compositors to have many options while composing the final image and/or rapidly establishing the right light balance. All the layers are rendered simultaneously. Adding many layers do not generally increase rendering time significantly. Windows only: Writing to disk many Image Layers may result in a performance bottleneck on Windows file systems. This is not the case on more efficient file systems such as Linux (ext4) and MacOSX (hfs+).Overview
The Image Layers group
Global Options
Default Image Filename
Specifies the default file location for the image layers. By default, the location is based on the scene name, the render pass name and the AOV name. See File Path Expressions for details on how it is possible to construct relative paths and paths containing dynamically expanded tokens.
Default Image Format
Specifies the default file format for the image layers, including the pixel bit depth. The default is 16-bit float EXR files. Many formats are supported and each have specific options for bit depths. Refer to Image File Formats for more details.
Batch Output Mode
Each image layer have a file output toggle controlling wether it should be saved to file during rendering (this is explained below). Since these toggles may be manipulated frequently while working interactively and may be forgotten in a off position when sending the rendering to a render farm (using the Maya Batch command line), the Batch Output Mode controls wether these toggles should be ignored (overridden) when rendering in batch mode. This option is useful to make sure all image layers are saved when rendering using the Maya Batch command line, regardless of the status of the file output toggle. The options are:
Enable file output as selected | Indicates to output the image layers to file (in batch mode) only if their corresponding file output toggle are selected. This is the default, it follows the same behaviour as in interactive mode. |
Enable all file output and selected JPEG | Indicates to ignore (override) the file output toggles and request that all image layers be saved to file when in batch mode. With regard to the output of a JPEG file, only those that are selected will be output to file (meaning the Batch Output Mode have no overriding effect to the JPEG output toggle and those are output only if enabled, wether in batch or interactive mode). |
Interactive Output Mode
The Interactive Output Mode allows to globally control the behaviour of the file output toggles while working during an interactive session. The options are:
Enable file output as selected | Indicates to output the image layers to file (in interactive mode) only if their corresponding file output toggle are selected. This is the default behaviour. |
Disable file output | Indicates to disable the output of the image layer to file (in interactive mode). Both the regular and JPEG file output toggles will be ignored. This is useful while working interactively and displaying image layers on screen only and to ignore the file output toggle (and possibly let it be used for batch mode only). |
Enable file output only for selected displays | This is an hybrid option. While working interactively, one may be interested to output to file only those image layers that he is actively working on: those that are selected to be displaying on screen. With this option, the image layers will be saved to file only if the display on screen toggle in selected. |
List of Layers (AOVs)
The second section of the Image Layers group is use to specify the list all the layers that will be generated during the rendering process (subject to the selection of any of the three output toggles in te list). By default, the list is populated with only one image layer, the RGBA ("Beauty") layer. When there are many layers, it is possible to re-order them in the list for organisational purpose (to visually group them). This is done through a middle-click and drag. It is a bit finicky to use though - you need to drop the layer while a line in between two layers is highlighted for the re-order to work. If you drop the layer while another layer is highlighted, nothing happens.