Revit is not good enough for Octane...
It is not good enough for Maxwell (they just released their plugin)
Everything will work OK if you use Revit with Max and Octane (or Maxwell, I an a big fan of both) and maybe a plugin like ForestPack.
This is my workflow...
It is silly if not more, to deal with Revit which is probably the best BIM software but the worst generic modeling app ever!
Not only you can't use millions of free objects (import obj or 3ds) but you can't even make such things!
There is a reason for this... Adesk's modeling and rendering app is MAX... Revit is a building modeler, that's it!
The biggest error was to add rendering inside Revit... the worst was to think they did a good job!
AutoCAD,Revit Architecture, Max Design (all 2012) , Moi3D,Maxwell Render,Octane Render
Intel i7-8Gb RAM - Win7x64 - GTX550Ti