Haze

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daros
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Haze

Post by daros » Thu Sep 09, 2021 3:21 pm

Hi, is it possible to use luxcore's volumetrics in order to create haze like this?
Thanks
Haze_in_Mountains.jpg
Haze_in_Mountains.jpg (8.13 KiB) Viewed 209 times

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B.Y.O.B.
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Re: Haze

Post by B.Y.O.B. » Thu Sep 09, 2021 4:14 pm

Yes. For example, you can surround the scene with a big box that has a null material with homogeneous interior volume. Use a very low scattering value, something like 0.001.
Remember to set the same volume as exterior volume of the camera, if the camera is inside the box.

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Sharlybg
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Re: Haze

Post by Sharlybg » Thu Sep 09, 2021 5:43 pm

B.Y.O.B. wrote:
Thu Sep 09, 2021 4:14 pm
Yes. For example, you can surround the scene with a big box that has a null material with homogeneous interior volume. Use a very low scattering value, something like 0.001.
Remember to set the same volume as exterior volume of the camera, if the camera is inside the box.
Because of the simplicity of the Workflow in felix they use world volume. I mean No box mesh so that the user have a check box plus few simple settings.
But i guess the principle is the same. Don't know also but i've seen simillar effect being applied in sky model.
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B.Y.O.B.
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Re: Haze

Post by B.Y.O.B. » Thu Sep 09, 2021 6:53 pm

The problem with a foggy world volume is that it makes all light sources that are infinitely far away basically unusable. That means the sun, infinite lights like HDRI backgrounds, sky etc.
If you want to have some light haze in the scene with a sun and sky overhead, you'll need to use a fog box mesh to define the boundaries of the fog. You could probably automatically compute a good size for such a box from the scene geometry and the position and direction of the camera (don't make the box larger than necessary because that enlarges the scene bounding sphere, which can lead to numerical precision problems with infinite light sources).

daros
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Re: Haze

Post by daros » Thu Sep 09, 2021 7:14 pm

Great, thanks. I think we can manage to automatically build a bounding box with reasonable proportions for this purpose.

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Sharlybg
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Re: Haze

Post by Sharlybg » Fri Sep 10, 2021 8:03 am

B.Y.O.B. wrote:
Thu Sep 09, 2021 6:53 pm
The problem with a foggy world volume is that it makes all light sources that are infinitely far away basically unusable. That means the sun, infinite lights like HDRI backgrounds, sky etc.
If you want to have some light haze in the scene with a sun and sky overhead, you'll need to use a fog box mesh to define the boundaries of the fog. You could probably automatically compute a good size for such a box from the scene geometry and the position and direction of the camera (don't make the box larger than necessary because that enlarges the scene bounding sphere, which can lead to numerical precision problems with infinite light sources).
Thanks for the explanation. It make sense now. I use always volumetric Box in my project in blender so I was thinking that world volume is exactly the same but more general.
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