Volumetric Fog feedback thread

[apq (Anton Palmqvist)]

@Drekkard;703443

Hi, could we have a step by step tutorial on how to create volumetric fog for newbies? I can’t understand how to set it up and can’t find any tutorial around.

Thanks!

I noticed that you have to crank up the Extinction Scale quite alot to get any noticable effect, so that’s maybe why it doesn’t seem to work for you.

It’s just 4 quick steps basically:

1. Place an Exponential HeightFog actor in your level.
2. Tick the Volumetric Fog checkbox.
3. Set Extinction Scale to 200.
4. Place a light in your level. You can also tick the Cast Volumetric Shadow checkbox to get the nice shadowing effect.

[Pixelpirates]

Thanks for volumetric fog, it’s great. One thing I miss though is the ability to check with lighting channels affect the fog.
In a project I’m working I’m using a separate lighting channel for a couple of lights that follow and light the main character but nothing else, and as it is now those lights light the fog as well as the character.

[Z-enzyme]

Huh, not bad.

Pity that with higher view distances it won’t work

Edith:

Not bad at all!!

Okay, it’s been a while since I’ve said something like…

What the actual ffff…

I just can’t help it… This is amazing!

[Envieous]

hmm

pretty cool

https://imgtc.com/i/YrPzvaH.jpg

excuse the blown out lighting, and the weirdness in some of my shaders 4.16 isn’t playing perfectly nice with copy pasted ut. I’ll have to give this a more in depth pass whenever ut gets ported.

Also, does this not work with static lights? I had to change mine to movable in order to get the effect to show up, perhaps lighting needs to be rebaked? I’m also still unsure of how to use the local controls to limit the fog strictly to the outdoors.

e: fixed up some shaders and updated the image

[KreatiVR]

Hi,

i also tested the volumetric fog and after a lot of tweaking it gives good results and it does what it should. You see 3 Lights in the same scene… 1 Ambient Skylight only, 1 Directional Light and 1 Spotlight. To get shadows in the fog for the figure and only directional light, i have to change a tick in the mesh: Dynamic Inset Shadow (under Lighting) has to be off.
Mybe there are other ways to get there, but i like what comes out now.

Ambient Skylight only:

Spotlight only:

Directional light only:

[anonymous_user_138c2332]

@Z-enzyme;703832

What the actual ffff…

I just can’t help it… This is amazing!

I’m sorry but in reality the atmosphere would get shadowed, in your case it’s not there at all.
Source

[anonymous_user_34d1a5911 (anonymous_user_34d1a591)]

The Atmosphere is there, shadowed and there

[ioFlow_Studios]

Just wanted to say thanks for this fog stuff, it’s a complete life saver for me where I’m at right now in Eden…

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Performance is fantastic on my 5 yr old laptop, lose 2 maybe 3 frames per second with fog .

Runs like forrest gump on my nice work machine of course.

[ldcue]

I though this feature would never come to UE4, it is really great it is finally in development.

I have some questions though (I haven’t tried the UE 4.16 Preview):
Does this mean we obviously no longer need some mesh with tricky materials to fake the volumetric fog/lighting inside buildings and in dark areas? If so, what is the performance cost when using this feature?

[Z-enzyme]

@Ley0k;706022

I though this feature would never come to UE4, it is really great it is finally in development.

I have some questions though (I haven’t tried the UE 4.16 Preview):
Does this mean we obviously no longer need some mesh with tricky materials to fake the volumetric fog/lighting inside buildings and in dark areas? If so, what is the performance cost when using this feature?

No, we don’t need any tricky material stuff there. The performance is good and it is tweakable by Console commands r.volumetricfog. + something, it will give you hints anyway, so you can adjust the number of samples, the jitter, the temporal blending, overall quality. But still, it is quite good I must admit.

About the sphere mask, you can also use BOX mask to create a box like fog.

[ldcue]

Also, are light shafts and volumetric light/fog totally two different things?

[anonymous_user_f2b8b290]

Ok I’m back from vacation, trying to catch up.

It seems that movable actors do not affect volumetric shadows casted by stationary lights. Look at the pictures below. The big cube to the left and dummy are movable actors. When the spotlight has movable mobility, any actor affects a volumetric shadow. When I set mobility of lightsource to stationary, after rebuilding the light, volumetric shadows are not affected by movable actors. Is it correct behavior?

Movable actors affected by a stationary light create per-object shadows and these are not supported by volumetric fog. Only the static shadowing is supported at the moment (or whole scene dynamic shadowing like CSM).

Some projects, (including our current project) just don’t use static lighting regardless of whether the light moves or not. It should ultimately be artist’s decision to exclude a light from being captured.

I can see how this is a problem when you might want to use Movable to get better quality. Or maybe you do move the light, but you prefer the reflection captures to capture it anyway. I think the default is good (exclude them) but I’m going to add an override so that if you have a movable light you want in a reflection capture, you can force it in there.

Also, does this not work with static lights?

Volumetric fog doesn’t yet support any static lighting (static lights, global illumination from stationary lights)

If so, what is the performance cost when using this feature?

It depends on what GPU it’s running on, and what shadow scalability level. Do ‘profilegpu’ on the target machines you care about. With default scalability settings it’s ~1ms on PS4 (High shadow settings), ~3ms on 970GTX (Epic shadow settings).

[SteveElbows]

Hope you had a great holiday - I am still really in heaven with this feature.

[Envieous]

@DanielW;707148

Volumetric fog doesn’t yet support any static lighting (static lights, global illumination from stationary lights)

Thanks. Can you elaborate further on how to limit the fog to certain areas?

[Purplepill]

Hi, found this thread and this new feature looks amazing,
can anyone explain how to set up the material properly to get it to work with a particle system or mesh?

I can’t seem to get the simple spherical fog volume like its shown on the first page.
Also when I make a new material i do not get scattering and absorption but albedo and extinction?
Do I have to check any more parameters on the material tabs?

Any help would be greatly appreciated.

[ldcue]

@Purplepill;709302

Hi, found this thread and this new feature looks amazing,
can anyone explain how to set up the material properly to get it to work with a particle system or mesh?

I can’t seem to get the simple spherical fog volume like its shown on the first page.
Also when I make a new material i do not get scattering and absorption but albedo and extinction?
Do I have to check any more parameters on the material tabs?

Any help would be greatly appreciated.

1. Setup a material like this :
   

2. Create a new particle, set its lifetime to 5.0 and its initial size to {50, 50, 50} so that the particle is more visible, and assign the material you’ve just created to the particle.

3. Place an exponential height fog on the level and enable Volumetric Fog on it.

4. Place the particle into the level.

5. Place a spotlight above the particle, and set its volumetric scattering intensity to 4.0 (so that the volumetric light more visible).

The particle should now be getting affected by the spotlight.

[2visual]

I am having this issue…before I run light build it looks great after…not so much. Any help?

[Purplepill]

@Ley0k Thank you very much it works

[2visual]

Spot lights seem to not cast shadows and SAVE THEM IN LIGHT BUILD. I have marked them as movable as I do believe that this is because they are overlapping with more than 4 lights. This may have nothing to do with the current build but I thought it is better said than not. I was never able to get a directional light to work correctly once saved.

[Chesire]

@DanielW > Thank you so much!

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