The V-Ray FrameBuffer allows you to load the various render passes which can be handy to see the initial rendered output for comparison. If however you are using Arnold, this would be a missed feature inside the Maya Render view window.
The Render Blog’s João was caught in this very situation and wanted to load and view Arnold aov’s in the Maya Viewport, and shares how he was able to do so using python.
he idea behind this is very simple, maya’s renderview has the ability to load images, and we will assign to each menu item inside the optionMenu a render pass
João provides a little insight into how the script will work, and walks through creating a simple user interface to facilitate easily loading all the render passes and aov’s right within the Maya RenderView.
João does note that if you are working in linear workflow and using 16/32 bit images like exr’s, you need to setup a few things so that it can work properly, most notably having the OpenEXRLoader plying loaded with Maya’s plugin manager.
To create your own Python Script for Loading Render Passes and AOV’s into Maya’s RenderView Window, check the post here.