Sorry I didn’t made myself clear.
I didn’t meant getting Vray straight into Unreal.
As I said, we can easily render to texture from any package that supports Vray (mainly 3Ds Max) and get those maps straight back in Unreal.
Therefore, something like VRayRawTotalLighting could be a good start, comping that with the diffuse filter and the reflection pass and you’re good to go.
Getting the diffuse and reflection/bump/normal/ etc is already possible, only the actual light information isn’t, because Unreal uses his proprietary lightmaps.
Lightmaps are just maps, maybe designed to work with Unreal for sure, but it would be great if Unreal implement getting lightmaps from other packages.
This would give us the possibility to export light/shadow calculation from other render engines like octane as you mentioned.
I’m sure it would take Unreal some work in the background to get it implemented (much or not?), but it’s just a decision they need to make
Otherwise they could stay with blinkers and continue to push their own implementation when other solution out there have already proven everything.
There are a million reason why Unreal doesn’t even compete to Vray for production reasons (try to render with 50 nodes only the lightmap of 1 chair or sofa in your room) and they (Unreal) will use a LOT of man power to try to re-invent the wheel when it’s just there, ready to be used.