Unreal take on Loft.

[anonymous_user_f2b8b290]

Fantastic work .

Changed few values in BaseLightmass.ini (only started to getting some understanding of it), still wrapping my head around photon mapping in Unreal. Don’t know why EPIC is not helping out artists regarding the workflow concerning Photon Mapping for realistic renders. I am more then happy to help but my own results are based on experiments with loose understanding of some values. Still very much struggling to solve so many problems in lighting. EPIC documents are not at all helpful.

We all know Rafeal and Koola are able to get the results we all desire (not talking about artistic look, but technically their renders are almost without bugs), so technique is there to overcome all the hurdles, but EPIC is not willing to share the workflow.

Why not make a making of - Unreal Paris - explaining every part, including Lightmass Settings (We all know the values which are available to “artist” are not at all helpful) with BaseLIghtmass.ini tweaking (it is not possible to get that kind of result without touching that ini file) , Proper Unwrapping techniques to avoid light leaks (great information is available on forums, but all scattered and untidy) and so on.

I’m the engineer at Epic that made the Lightmass solver, among other things. I can answer any technical questions you guys have about lightmass settings, BaseLightmass.ini, photon mapping, etc. I’m not an artist though and I didn’t work on the Unreal Paris demo.

Sorry for the sparse documentation, hopefully it’s something we can improve in the future.

Short summary on BaseLightmass.ini: these are all values for various internal algorithms that Lightmass uses. We tried to make it possible to get the best quality with just UI settings, specifically IndirectLightingQuality, IndirectLightingSmoothness and disabling lightmap compression. We never intended for artists to set these directly hence the documentation is in SceneExport.h in the Lightmass source code. However, we’re not going to stop you from setting them if you want, so BaseLightmass.ini remains.

I would love to know what you have to modify BaseLightmass.ini for, so we can incorporate those changes into UI settings. Basically, help us identify what could be improved. When I investigate lightmass quality for a level in depth (as I have done in Realistic Rendering, SunTemple, Berlin Flat and others) I just stick to the Lightmass WorldSettings and have not found the need to change anything else.

Right now I’m aware that quality in area shadows is limited on Production and I intend to increase the number of rays used in penumbras when you increase IndirectLightingQuality. (NumPenumbraShadowRays in BaseLightmass.ini)

Also I’ve noticed that many of the best UE4 ArchVis scenes use an IndirectLightingScale of .1 or so. This is not something we anticipated at all, that setting is meant to be used for speeding up lighting builds in huge levels by using a value of 4 or so. So there are probably a number of bugs that become exposed when using a scale of .1, and I would like to investigate.