Simulating fog

[Amerio.Stephane]

Hello,

I'm trying to simulate a heavy fog. I set the preset 1 intensity to 1.0 and its haze max distance to 5000, with a density of 1.0

Here is the result:

The moutains stands out with the expected fog value on a much darker sky (no clouds here). I would have expected the moutains to completely vanish in the fog. Indeed, the sky appearance is not affected at all by the haze settings.

What am I missing?

(note the fog distance will vary at runtime)

Edited September 13, 2018 by Amerio.Stephane

[Greg.Mildenhall]

Purely from a rendering perspective, you can't apply the same depth-based fog calculation to the sky and expect an accurate result because the sky doesn't have a real depth to base it on. So it shouldn't be a big surprise if you need to configure the sky separately.

[thomalex]

Hello,

the thing is with the Ground LUT Texture. This mask has gradual color transition in the Preset 1, which may cause such an unexpected darker look of the sky.

Our artists suggest using the ground texture of the Preset 0 (core/textures/scattering_lut/preset_0/ground.tga) or any other custom one with discrete color transition.
Also you can configure the sky separately by adjusting the Ground Color parameter or even setting its Alpha Channel to 0.

[Amerio.Stephane]

Thanks thomalex, your suggestion is rcorrect. replacing preset 1 ground LUT with the same as prest 0 fixed the fixed the haze !

So now, a questyion for Unigine dev: why would there be a different LUT for these presets ? Are we missing something ?

[silent]

Amerio,

Not sure that I understand your question correctly - could you please elaborate? These presets are specially designed for different weather (sunny vs cloudy). Different LUTs used to modulate different weather conditions (as it designed for).

Thanks!

[Amerio.Stephane]

The default preset 1 looks very artificial to me, giving solid light grey moutains against a darker background. Preset 0 LUT feels nicer.

Searching for real world reference, I found that for most of them the moutains would actually be darker than the sky:

https://pxhere.com/en/photo/1262581

[silent]

Amerio,

Can you please check the attached modified LUTs (they will be included in the 2.8 I believe). So the steps are the following:

1. Replace textures in your project's core directory (or UNG) with the attached in core.zip.
2. Change the alpha value to 0 in Ground Color in the Settings -> Environment -> Scattering LUT for all presets.

That should solve the dark clouds issue with haze.

Thanks!

core.zip

[Amerio.Stephane]

Hi Silent, the new images and setting the ground color alpha to 0 did the trick ! Thank you.

A few remarks: the new base.tga prest 0 gives much darker clouds, but the illumination of objects feel more realistic with the new one.

I also changed the Haze color for preset 0 to #76a6c6 (a slight blueish tint) to mimick the atomspheric filtering. Not sure if this is the correct way to do it.

 

Sidenote, small suggestion on UX: the settings should also highlight in green the parameters that were modified by the user, just like for node parameters, with the possibility to reset to default value.

Thanks !

[silent]

Amerio,

The thing is that there is no default parameters exists, due to the nature of settings itself - it's just loaded preset from .settings file (or .world).

When you create new world via editor a set of pre-defined settings (located in data\template_render_settings directory) are created automatically. You can double click on any settings file in Asset Browser to immediately apply it's parameters.

We do have plans on Settings window usability improvements and it's good idea to mark changes (but only until you apply them and save to a file) as green.

Thanks!