Light Propagation Volume Distance and Fade In/Out
I've been trying for a while to use Light Propagation Volumes for an open, somewhat large environment, but its limited range makes this almost impossible. Adjusting the LPV size via post processing volumes works to some degree, but even with a "maximum" value of 20000 I cannot cover nearly enough space to illuminate the whole scene. Any value higher than 20000 leads to way too much light bleeding and weird artifacts.
To counter this, it would be great if we could also adjust the resolution of the LPV instead of just adjusting the scale, in order to maintain quality even with an increased size. Another option would be having two LPVs: One for immediate environments and one for larger distances.
If that's not feasible for technical reasons, it would be nice to get at least better fading from and to areas illuminated by LPVs. In 4.8 and earlier versions of the engine the global illumination faded in to some degree, but had a very rough and distracting transitions when moving backwards. In 4.9 the transitions are rough in both directions.
I'm sure these features wouldn't be cheap in terms of performance - if they are possible at all - but it would be great to have the option. The game I'm working on does not require a lot of resources in other areas and it would be great to use them for better lighting. I'm also aware that Light Propagation Volumes are being developped by Lionhead, so I'm not sure if anyone here can comment on it. But it's the best chance I got! I love the overall results of LPVs and would love to use them, but as it stands the problems unfortunately outweigh the benefits.
There are 2 console commands you can use to increase fidelity on the Light propagation volumes:
I don't remember where i read that increasing the scale by 2 increases the computational cost by 8, or something like that. LPV is a nice effect, but its not very useful when it comes to big spaces with nothing blocking your view (I'm using it for my project and getting simillar problems to those you are having).
The other thing you ask for is cascaded LPV, it has been asked for before, but Epic is not really working on the LPV implementation, as you already stated; and nobody really knows where Lionhead is going with it. Personally I was loving DFGI but as it got left aside by now I'm playing around with LPVs in the hope of Epic resuming the work on DFGI before its too late for my game to implement it.
PS: You might want to take a look at AHR for global illumination if you are not getting performance issues from rendering. You can look at it here Or you could try using Nvidias VXGI, its really expensive in terms of performance and pointing more to "next gen" PC games.
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