Re: Arnold Volumes Object ID type of AOV?

[Jason S]

Are you exclusively using pure Red Green Blue (and Alpha) as your tile colors? (or are you using deep images?) Because otherwise you cant use object ID colors to isolate elements of variable opacity midpoints (inherent to volumes) to get something like this (below) once isolated.    For the same reason (non-deep) arbitrarily colored objectID images are typically rendered at 2X+ size, to extract grayscale tiles (white (1)  OR black (0) ) and then resize down to have antialising midpoints around edges of isolated elements. Or perhaps not as convenient as for all other elements with ID's, but how about just setting-up a pass for your volumes with all objects black (with black alpha)? On 08/30/15 6:18, Perry Harovas wrote: Hi all, Sorry to ask this here. Have asked in other places with no real response. Does anyone know if it is possible to have Arnold output what is essentially an object ID pass (different colors for each object) but for volumes within Arnold? I have some VDB smoke, then some other smoke in a different VDB. They both use different Volume_Collector shaders with different settings. Is there a way to spit out a pass that shows me the volume, but lit flat so I can use it as an object ID mask to tweak inside of Nuke? I can get all the geometry in the scene to output a Object ID AOV except the volumes. They are rendered lit with shadows and lighting colors, etc. Without having to render a totally different pass, is there a way to output an AOV that can isolate the volumes, each one differently with a different color for each volume, so I can tweak them independent of each other? I can use the Volume Opacity AOV, but it outputs ALL the volumes as one color (white, with transparency) in the resulting AOV. This would be perfect, if each volume had a different color, not all the same white color. Hope this is clear. Thanks for any help! Perry