If by “stationary lights” you mean lightmasses it is very inefficient in term of pipeline (mainly because of the process of building it) and this is a mostly static technique. The “post process Global Illumination” is just a setting that setup how lightmass are displayed on the final render (the documentation). So there is no dynamic GI on OSX/linux (and nothing “production ready”).
I hope you guys are working on a fully dynamic GI technique, I don’t care if it’s LPV, radiance hints, VXGI or Deep G-Buffers based stuff just please anything more dynamic than this lightmass T__T
Hello,
I’m working on a game where we need a global illumination and a fully dynamic one enable a faster iteration process that’s why we decided to try LPV. The feature itself is good enough for what we need (okay colour bleeding, good tweak possibilities, not too demanding performance wise and fully dynamic).
The problem is that my team use all OS where unreal is available, I didn’t try on linux (yet) but on OSX I couldn’t make it work. Here is what I did to test the feature:
I created a third person blueprint
project on UE4.16
added r.LightPropagationVolume = 1 in
ConsoleVariables.ini and restarted
the engine
made something like cornell box using
6 cube and a sphere Mesh all in
movable
put the sunlight in movable and
checked “dynamic indirect lighting”
enabled “force no precomputed
lighting”
enabled show->visualize->Light
propagation volume
add a postprocess Volume in unbound
set “Light propagation volume”
intensity to 10 (to be sure tu not
miss it)
check if show->light
component->Global illumination is
“true”
Which is obviously just direct lighting + the sky color and that’s it, no color bleeding at all (maybe some highly dithered AO).
I’ve read multiple time that LPV aren’t supported on OSX because their version of OpenGL (4.0) doesn’t support compute shader. But OpenGL on OSX is dropped since a while now and unreal only use metal (which support compute shaders). So it would be great to get this very convenient feature that requires no building, very highly configurable (great for stylised render) and doesn’t depend on any additional information placed by hand on the map.
I’m not against another GI technique but I it must not requiere to place boxed and work on dynamic objects (it’s limited on static meshes that’s ok).
I tried use lightmass but except performance wise it’s inconvenient on almost every aspect
(100% static, ignore dynamic object in the building, only “diffuse boost” to stylise render, requires placing boxes etc…) for a not so great result.
So the short answer here, which you point out in your description is that OS X doesn’t support the Direct X 11 compute shader, which is necessary for LPVs to work. Metal’s compute shader is going to run a similar path, but still is not DX11. What you are seeing and reporting is expected, and the limitations are outlined in our documentation.
These are also still considered experimental and not production ready, so even if you had the correct platform, it might not work well in your final project like you want. I would look at using Stationary Lights which have dynamic functionality, as well as the Post Process global illumination methods to manage and control your scene’s lighting.
