Video tutorials about using AOVs in MAXtoA can be found here.
3ds Max does not support more recent EXR formats natively, and you may have issues using Arnold generated EXRs in your scenes. EXRs with only one layer should work.
AOVs are similar in concept to Render Elements, in that they separate out components of the rendered image as it is produced, and sends it either to a separate output file and/or as a channel in an EXR. Arnold supports output types and features not found in Render Elements.
The Arbitrary Output Variables (AOV) window is available in the AOV tab in the Render Setup window. Here you can choose to Add AOVs using the AOV Wizard or manually using the AOV List. AOV light groups can also be managed using the AOV Light Group Manager window.
The main view shows an AOV list to add Drivers and AOVs (drag & drop). Roll over image to view AOV List.
The main view shows a wizard where you can Add Drivers and AOVs (also available in the + Add AOV File menu).
Creates a default RGBA (beauty) AOV. Disabling this (on by default) enables you to add individual component AOVS.
Here you can choose to split direct and indirect AOVs.
Split direct/indirect AOVs (All in One File: disabled). Combined enabled. Roll over image to view Combined: disabled.
MAXtoA takes a file-centric approach. You start defining your AOVs by first specifying the file type (+ADD AOV File) that you want to produce and then the AOVs you want to save to that tile type.
Drag & drop AOVS from the AOV list into the main area where you can adjust the type, driver, and filter of the chosen AOVs.
The filename of the AOV. The name of the output files can be renamed here. Multiple AOVs can be dragged onto a single AOVs group. This can be useful for light groups where you might want a diffuse AOV in both a red and blue light group.
Here you can choose the file type (driver) format which you want to output from MAXtoA.
The AOVs use the image pixel filter defined in the Arnold Renderer tab. Gaussian is the default.
Same as File: (only available for AOVS) - The AOV will use the AOV Light Group setting defined at the file level. Same As File, All lights or default.
All lights: The AOV(s) will be rendered using all lights, regardless of AOV light group assignation.
Default: The AOV(s) will be rendered using the scene lights that are not assigned to a light group (or are assigned to the "default" light group).
Choose to remove all AOV files from the main pane.
Opens the light group manager window.
Choose to load/save different AOV presets.
You can define custom AOVs in the scene via the Add Custom AOV button if you want to render a custom effect that is not available from the existing AOV list. This custom AOV can be used with any compositing software such as Nuke. You can write the output of a shader in a custom AOV via an aov_write shader.
Tokens (select a token), Select Output Folder and Open Output Folder
Tokens are used to generate dynamic AOV output paths. You can use tokens to define both the folder structure and the output filenames. If the generated path does not end with a valid filename extension (EXR, png.), the default name and extension of the AOV file will be added automatically.
If the output expression does not end by a valid file extension, the expression is assumed to be a path. The current valid end of expressions (extensions) are (case insensitive):
.exr, .deepexr, .jpg, .jpeg, .tiff, .png and .<AOVsFileType>
If the expression resolves as a path, "/<AOVsFileName>.<AOVsFileType>" is added for a single frame, "/<AOVsFileName><Frame>.<AOVsFileType>" is added for a frame sequence.
Tokens are case insensitive.
<Frame> uses zero padding, 4 digits.
1. Output paths
2. Output files
The example below shows a plane with a checker texture connected to standard_surface.opacity. Currently, we do not support opacity composition in AOVs of RGB types.