
Hopefully this is going to work beautifully, but I doubt it will be efficient when I am trying to bang out dozens of chunks/parts for what I need (we all have different needs - mine require splitting renders into many parts). This is one reason why guys like me and Boris want something in Object Layer or Matte that completely masks stuff - and an alpha-enabled image (either saved PNG32 or in viewport) is perfect-a-mundo and ready to drag and drop.
I am all for the complete control and capabilities that EXRs and (planned) Passes affords and look so forward to getting my hands good and dirty with the new goodies - about a third of my work is complex render comps into existing photography and does not require the bs I describe above... but in my honest opinion, it would make Octane even more marketable to folks that want an option to do simpler/quicker comps, some of which might be a-scared of EXRs and passes...