Although the Arnold Render is still in beta, the release candidate 3 out there, so it feels like it is getting close. A new post from the MaxDepth blog notes that there isn’t a dedicated AOV for getting a volumetric scatter in Arnold, nor will there be one for the release – But, Timothy Hanson does show a couple of methods on how to get around this and render and composite volumetric fog with Arnold, Maya, and Nuke.
how to create volumetric scatter fog with Arnold for Maya, and how to comp it in Nuke 8
Timothy walks through a couple of solutions including an old-school one of using Maya’s render layers with layer overrides and mattes. The idea is that if you build your scene, you can create a separate render layer and make the matte function active for the ai_Standard shaders and render your layers accordingly. Another method Timothy covers is combining the standard AOV’s and use a merge function with the beauty pass in Nuke.
Check out the tutorial for Creating & Compositing Volumetric Scatter with Arnold for Maya and Nuke 8 over at MaxDepth here.