Since many of us are really keen on seeing SVOGI in the released build of the UE4, I am wondering whether it would be possible to release the old source code of the SVOGI implementation and have the community integrate it into the latest UE4 version and maintain it. This way Epic wouldn’t have to worry about integrating SVOGI, while making many of us very happy.
Even though SVOGI might not be a viable option for many games at the moment it would still be a great solution for a realtime GI preview in the editor.
We chose to remove SVOGI in order to reduce our maintenance burden and allow us to iterate more quickly on other new and exciting features. It takes a considerable effort to maintain a complex system like SVOGI as the engine grows and evolves: every time we add a new feature or modify an existing feature we have to ensure that it works with all existing features.
For that same reason we do not plan to re-integrate SVOGI in to the main branch of UE4.
We are considering other options but SVOGI has tendrils throughout the rendering code so it is not a good candidate for a plugin right now. It would also be a considerable effort to get it working again with the latest code.
A lot of our efforts recently have focused on improving static lighting in UE4. That was motivated by bringing up the mobile renderer where static lighting is still largely required as well as looking in to solutions for games that want to target high frame rate (usually 60fps, higher for VR!) while also maintaining a high visual bar.
I think dynamic lighting is an important feature and workflow for many games and we will improve our dynamic lighting features over time. UE4 now has experimental support for Light Propagation Volumes as some have pointed out and I think that can be a good solutions for some games. We will work to improve LPV and we have other ideas we plan to explore to provide options for games that do not or cannot rely on Lightmass.
Wouldn’t it possible to just add a github branch (or even a separate repository), that had the old svogi code in it? That way you guys wouldn’t have to do any more work on it, and it would allow the community to use it in other projects, games, or forks of the engine.