Sorry, I'm not sure to understand you. What do you mean by render passes? If you want to attach your scene, we could take a look at it here.

Thanks,
-Juanjo

like an ambient occlusion pass, diffusion pass, or light passes. You render out these files separately usually as an .EXR to manipulate ...

i'm having a hard time figuring out which render passes i should select for rendering out an explosion i simulated. I was following a tutorial from cgcircuit but he's using mantra and their render passes have different names

everytime i try to render it says it's not octane material and the render just gives me a white background with a gray circle. No fire no nothin.
You need to export the phoenix fd grid as a VDB grid :
https://docs.chaosgroup.com/display/PHX3MAYA/Output

Then create a volume object from Octane menu ...

everytime i try to render it says it's not octane material and the render just gives me a white background with a gray circle. No fire no nothin.

Hi goku223344,
Octane supports PhoenixFD without exporting .vdb. Octane can use fumeFx and realflow through .vdb. Fumefx will be supported, this is in the developers to-do list.
Regards
Paride
Ok that makes sense, I have two questions. How to do I simulate .vdb files directly in fumefx. And if I ...

i want to know if you can render all particles including particles from fumefx or realflow straight from octane without the use of openvdb or anything like. Really thinking about buying it.