Implementing Reflection, refraction and indirect lighting to Gbuffer


Working for a film and VFX studio I am currently figuring out how to use the Unreal Engine 4 for filmmaking and video rendering to reduce render time adn combining 3Ds Max with UE4 within Nuke. I have now, after 3 days of constant researching gotten to the point where UE outputs me around 20 passes per frame ranging from base color over stancil to custom depth but some very important passes are still missing. The reflection, refraction and indirect light passen to be accurate. And maybe some more, I’m not a compositor so I’m not sure what else is needed.
Now I have also found a variable called “Indirect Irradiance” in the PixelInspector tool, so I think there must be a way to render out this pass too.

Looking further into the Gbuffer and talking to a member of Epic Staff I found out the following:

These 3 passes are not oncluded in the Gbuffer

There is a workaround for indirect lighting: Disable all directional lights and screenshot the indirectly lit object using white textures on meshes.

And there is a way to add new passes to the Gbuffer:

We do have a Python/C++ Dev inhouse who would, I assume, be able to develope a tool to render out these passes too, since at least the fitting variable for the light seems to callable and the other ones just have to be found.

If the interest and need is there of the community and other artists is high enough I might be able to talk him into devepoling this tool and making it public. After all it only benefits his idea of using UE for film making.

I would love to get some opinions on this and some feedback.

I could also be on a completely wrong track and this is not possible, then please feel free to correct me. Since I personally am still very new to UE and game/film making I’d love to get some helpfull advice and gather knownledge.

Best Regards
-M try using these. You can set them in the console as well with the showflag.x command.

Thanks a lot, seems like exactly what I need.

But…How exactly do I use these? What will inputting them in the console do? And what does SHOWFLAG_ALWAYS_ACCESSIBLE mean?
Sorry for newbquestions, still rather new to UE and rendering…