I get what you are saying and i’m not arguing against the fact to find bugs and move a tech forward, I disagree that UE4 ray tracing is comparable to offline render quality, to my eyes it is very very far off still, and even more time consuming to get somewhat similar results if you do, and if you want to use it for indoor renderings it is even worse. and it will be so even with many bugs fixed in the future. But if it works for your needs then great.
As for using UE4 in production I keep saying that it is not only the issue of just rendering inside the engine but also the issue of how a pipeline works with imports/exports/caches/material setups compatible with the engine, massive slowdowns and issues with alembic, lots of crashes with slightly more dense poly scenes and many other related problems with lighting and such.
Of course i am speaking of scenes other than just a few static meshes in a arch viz scenario. We concluded 2 projects using a game engine for the first time, client based projects with very tight deadlines allowed us to experiment a little, and it included characters and quality expectations were according to the budget given.
But we opted to jump into Unity halfway simply because we couldn’t import anything inside UE without the engine massively slowing down with alembic files and sequencer constantly crashing rendering 3K/4k sequences (for antialiasing purposes). We had no time to "optimize our scenes further and unity just handled it fine for what it was.
We almost missed our deadlines because of such unexpected problems and even with unity we were wishing to invest in a few more GPU’s to go back to rendering offline.
The setup times and troubleshooting for such simple scenes is just not worth the rendertime advantages. That is the case with most other teams working in larger vfx houses we know of as well.
They would rather invest in a GPU renderfarm which would cost them less than 5K even 2K and have a frame render under a minute with far superior results, less material and light hassles, no import/export issues and times wasted, lots of cheating because you can in a 3d app and lots of compositing layers output for free. fitting right into an existing pipeline.
By the time all these are “addressed” in a realtime engine of the future we would get GPU’s so fast that offline GPU rendering will be able to render far more complicated scenes with far less or comparable times as in a realtime engine and the gap will narrow down further still.
And so unless there is a very special case, investing time to make realitme raytracing in a game enigne work for production requirements is from my personal point of view a waste of time for todays needs as well as for the future.
But this doesn’t mean not finding bugs and helping it work for games of course. that is entirely different and well welcomed feature. The OP and many others though “seemed to be” trying to make an actual product out of it and I assumed that in any normal given world scenario they would have deadlines and such, which is why I told them to stick what works.
If they are just playing around features then so be it.