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DFGI issues in 4.13

Development Discussion Rendering
#1

So in 4.13.2, I can’t get dfgi to work. Dfao works fine (albeit with some strange artifacting) and all looks good in distance field visualization, but r.distancefieldgi has no effect. On a potentially related note, dfgi causes a crash when launching or packaging (haven’t really debugged, just build failed unknown err). Indirect lighting strength does actually have an effect though… it causes point lights (seemingly from lpv) to pop up all over the place, and pretty randomly at that. Lpv settings in an unbound post process volume have seemingly no effect (including injection bias, my first guess). I’ll provide images soon. Also, there is no dfgi-specific visualizer button showing up.

Thanks everyone!

#2

Alright so on a potentially related note, for some reason, I decided to switch shader model to mobile, and when I switched back, my screen antialiasing is behaving strangely, (all settings at epic by the way), and the environment doesn’t move unless I move around (all aspects, materials, particles, everything). My particlesystems won’t spawn either. Everything works fine when I launch or package though! I’ll provide screenshots of the lpv being weird as discussed above:

Below you can see evidence of DFAO functioning properly

Untitled.jpg

Here you can see the scene:ScreenShot00000.png

Here you can see zoomed in to the area below (as to remove bloom effect) the cube (emissive shading RGB = 10,10,0).

ScreenShot00001.png

Please note, the skylight and directional light are set to movable, i added an extra command to ensure mesh lpv is set to 1, indirect lighting is turned up, and in general, fiddling with settings does nothing…

#3

Another image with different emissive settings, and light propagation volume visualization

ScreenShot00002.png

#4

FYI, in the above, there is no actual lighting going on on the surface below, emissive strength is just multiplied…

#5

So on another related note (and I’m truly sorry for the spam replies, though, to be completely honest, I don’t see anything wrong with them from a user and not moderator’s perspective), I can’t reproduce the lighting effect with the weird LPV from earlier, but I can tell you, it looked something like this:
Untitled.png

#6

Alright so, in order to help with troubleshooting, I’m going to continue to post updates:

I just discovered indirect lighting is, to some extent, working, but not with distance fields:
ScreenShot00001.png

Also, here’s the weird LPV I talked about:
ScreenShot00001.png

In the upper picture, I use the red cube, but it is only shining light when exposed to the directional light behind the wall (outside), and the light bleeds through (hinting that distance field not happening but instead, LPV, as light bleeding is considerably less present in DFGI).

In the below picture, you can see the strange spots I talked about. They clearly behave strangely.

Changin LPV settings from defaults (as seen below vs above), has no effect:
(actually, I’m getting “database error” from forums…
just take my word for it :smiley:

#7

Opps wrong second picture… here is correct one:
ScreenShot00000.png

#8

I’d like to troubleshoot hat weird anti aliasing visible in the lights as well, really grainy in general, seemingly related to normal maps…

#9

Probably start with the fact that LPV and DFGI are different GI systems unconnected with each other and you shouldn’t be trying to use both at once

#10

Oh… Ok that’s interesting. Thought you had to… I’m really sorry, thats a pretty silly mistake. I did test with DFGI alone in the past and it wan’t doing anything, I thought they had to be used together. My apologies.

#11

Alright so with dfgi alone enabled, I’m getting similar results. Emissive meshes alone without a directional light don’t produce any glow either… Is that supported? (emissive DFGI)

#12

Same results:

ScreenShot00005.png

#13

Yeah, the spots on the walls are affected by iindirect llighting intensity only of the directional light. This applies to the test scene seen earlier with the cube…

#14

ScreenShot00001.png

Yeah this is definitely a basic matter of user error
The above is a screenshot out of a fresh new install of 4.14.0
Notice the pink circle that appears on the lower left hand side of the rear wall…
Movable skylight and directional light, but skylight settings other than immovability have no effect.
“Affect indirect lighting” on an emissive cube had no effect in the same scene, but “affect distance field lighting” did.

Hopefully this narrows things down. Dfgi=1 is the only command used (typed properly of course)

#15

I tested a landscape, height field GI is definitely working…

#16

Pretty sure DFGI doesn’t support emissives, spotlights or pointlights. Just directional light, and needs a skylight to work at all.

#17

Ok. Regardless, even with a skylight, and directional light, it isn’t functioning properly. I’ve provided as much info as possible, what can I do to troubleshoot?