Exporting the multi-render passes for compositing in Composite

After setting up your render layers and creating your render passes in Maya, you may want to export your elements to be composited in Composite.

Select Render > Export Pre-Compositing. The Export Pre-Compositing window appears.
The Export Pre-compositing editor is divided into three tabs: Cameras, Render Layers and Render Passes. Select the appropriate tab depending on the elements that you want to export.
Use the icon to expand the render layer, render camera, or render pass hierarchy and select the elements that you want to export. A icon indicates that all elements are being exported and A icon indicates that only partial elements are being exported.
Enter a scene anchor name in the Pre-Compositing Scene Anchor field. Composite uses the scene anchor name to identify the elements that should be included in the composite. If a composite with the specified anchor name does not exist, Composite builds a new one and adds to it all the elements with the same scene anchor. Otherwise, if the composite already exists, it is updated and all elements with the same scene anchor are included in the composite.
Note
Unlike the scene name, which can change, for example, from version one to version two, the scene anchor does not change. It uniquely connects a Maya scene to a scene composition in a Composite project. All elements that belong to the same composite, for example, cameras, render passes, render layers, and so forth, should have the same scene anchor. A scene anchor is only required if you plan to updated your scene compositions in Composite.
Click the Export All or Export Selection button to export your render layers, passes and cameras to Composite. The Export PRECOMP file window opens that allows you to enter a filename for your exported file.

Note

Before exporting to Composite, ensure that all your scene elements are named correctly. Avoid renaming elements (for example, a camera name or a render pass name) halfway through your workflow. Composite does not recognize the renaming of scene elements, since renamed elements are flagged as new elements to be inserted in the compositions. Therefore, if your composition contains old and new elements, you are responsible for cleaning up your composition after an update. For example, if you export for the first time with camera1 and then change your camera name to camera2 and export again, Composite does not update the camera in the composite from camera1 to camera2. Instead, your composite now contains two cameras: camera 1 and camera 2.

Using templates with the pre-compositing workflow

You can also create a template that instructs Composite on how to update the composite. A template is a Composite precomp file with nodes that contain anchor information. For example, if you have 15 passes in your scene, but only 2 of the passes are blended together in the template, then only these 2 passes are blended together in your composite. Specify a template for each layer using the Render Settings window, Passes tab. When Composite sees the template, it duplicates it, and then looks for the elements with specific anchors (render layer/camera/render pass anchors).

Create and use a template with the pre-compositing workflow

Create a template by exporting your scene elements to Composite. A composite is created.
Add compositing operators, such as blend and comps or math compositing nodes, to the composite and save it as a .txcomposition template file.
Use a different template for each render layer. Select a render layer and open the Render Settings window, Passes tab. Enter the template in the Pre-Compositing template for attribute. Repeat for each render layer.
Select Render > Export Pre-Compositing to export the scene elements to Composite.

File formats supported by Composite

Refer to the following table for list of file formats that Composite supports, as well as their supported bit depths.

Format	File Extension	Supported bit depths for imported files
Bitmap	.bmp	8
Cineon		10
DPX	.dpx	8, 10, 16
HDR	.hdr	32
IFF	.iff	8, 16, 32
JPEG/JFIF	.jpg, .jpeg	8
OpenEXR		16 bit float, 32
Photoshop	.psd	8, 16
PICT	.pict	8, 16
PNG	.png	8, 16
QuickTime	.mov
SGI	.sgi	8, 16
RGB	.rgb	8, 16
Targa	.tga	8, 16
TIFF	.tif, .tiff	8, 16, 32
Softimage	.pic	8
RLA	.RLA	8, 16

Note

Bit depths 8, 10, and 16 are integer unless otherwise indicated. Bit depth 32 is float.

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