Exponential Height Fog with Spot light Pixelated

Development Rendering
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1

Hi guys,
I’m simply trying to do some volumetric light using ExponentialHeightFog and all, and get some pixels at light source.
What I really want is some STRONG volumetric shadows and strong light (nearly white at emissive points). Juste like some auto lights with gobo can provide : High brightness 60W Moving Head Gobo Light.MOV - YouTube
But still there’s this resolution

252726-capture.png

at the benning of my light.

Any idea guys ?Seems like most of the time the light is being casted realy far. Guess I’m missing something here.
Regards

2

Hi Markmze,

What is your engine scalability settings and lighting quality set to?

3

Hi ,
well, cinematic and production quality

4

I took a look on my end and only received this particular issue on a lower quality settings. Can you provide me with your project so I may take a deeper look into this?

5

Actually, it’s a bit better on cinematic and production quality, but still quite pixelated at origin.
Here is a blank project with the issue : http://lookcloser.fr/VOLUMETRIC.zip
thanks for your time

6

Thanks a lot . I was as well thinking about the fog ‘quality’ or ‘resolution’ to be the issue instead of any lighting parameter, while not having any fog parameter to change in the editor (I mean settings to adjust on the actor).
I’m gonna have a look at this using this command.
I know this is going to be ressource expensive… Waiting to test the raytracing on unreal soo, and the way it can manage volumetric lights.
regards

7

I took a further look into the issue, and this is something that is going to be expected since volumetric fog is inherently expensive. When you lower the quality it uses fewer z-slices to reduce the quality of the fog which is what causes the pixelation that you are seeing.

You can try adjusting r.VolumetricFog.GridSizeZ to improve its quality, but keep in mind larger numbers will be more expensive. Additionally you can also lower the lights intensity a bit to make the artifacts less noticeable, then adjust the fog settings to achieve the look you want.

Let me know if you have any other questions.

Thanks,

8

where is the grid parameter ? I dont see it in the editor ?

9

It’s a console parameter

10

so I ask the players to open the console and type a command ? seriously ?

how do you set this in the editor ?

11

Ahah no, you can execute console commands through blueprint, look for it

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12

ok, look more like a hack

the bp calls the console to change an api setting…meh, if we dont have any other choice…
thanks mate

13

how does one check it’s current value ?

I tried show r.VolumetricFog.GridSizeZ, it does nothing on the screen and the console disapear

in a blueprint , the value (float or int) is zero

14

ok you mean in the editor show button

I wanted to know the value of the variable

if I change it, the engine crash

15

Show, visualize, volumetric lightmap

16

Lower is higher quality, but more expensive

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17

I cant change it, is it an integer ? a float ? what range ? unreal crash if I change it

also show viz vol lightmap does nothing

18

sorry, i’m wrong :
"Scalability settings are basically just presets containing different console variable values. The Shadow Scalability setting affects two CVars for volumetric fog (aside from r.VolumetricFog, which enables/disables the effect entirely):

r.VolumetricFog.GridPixelSize (Lower is higher quality, but more expensive)
r.VolumetricFog.GridSizeZ (Higher is better quality, but more expensive)"
I cannot find any range value information

1 Like