Author Topic: Volumetrics in Physical Material cuts out reflect underneath  (Read 2100 times)

2024-03-28, 16:51:25

blauwfilms

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Hello Forum,

I've been working on a Planet Earth setup and I'm getting stuck when applying a layer of Clouds.
The setup uses multiple spheres that are stacked on top of each other. From bottom to top:
• Earth (Layered Material: Land + Water [using a Mask])
• Fog (Using a textured Volume Material)
• Clouds (Physical Material with Opacity Map [for Cloudy areas] and Volumetrics)

When the Clouds layer is turned out I get a very strong Reflection that covers the planet.
The sunlight is unable to shine through the Clouds Layer (See attached images)

I've also attached images of the material setup for the Clouds.
I have a feeling as if that could be where the issue is?

If you have any questions of the setup, feel free to ask :)
I'd love to find a solution to this.

All the best, Leo

2024-03-28, 17:07:56
Reply #1

maru

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It could be related to the way various volumetric media interact with each other. What happens if you change the IOR of the clouds material to 1.0?
What happens if you use a Corona Volume Material for the clouds instead? (absorption can be used instead of opacity: pure white absorption = 0 opacity)
Marcin Miodek | chaos-corona.com
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2024-03-28, 17:51:55
Reply #2

blauwfilms

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@maru Ah great tips! Let me try that now.
The reason I opted for a Physical Material with Volumetrics was that I wanted to use Displacement.
Is there an alternative that I could use in a Volume Material?

2024-03-28, 19:12:44
Reply #3

blauwfilms

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@maru Changing the IOR to 1.0 actually changed quite a bit! Thanks!
It allowed more light to come through. The first image I've attached uses the IOR of 1.0, a Displacement map and Volumetrics.
The second image uses a Corona Volume Material. As you can see it doesn't have any Displacement and I don't know what workaround I could use to get that in there.

I'm rendering out a pass now with the clouds over the Earth material with all the other volumes turned on.
Let's see if it still works :)

2024-03-29, 10:35:30
Reply #4

maru

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You can create a Corona Volume Mtl with displacement this way. :)
Marcin Miodek | chaos-corona.com
3D Support Team Lead - Corona | contact us

2024-03-29, 15:58:55
Reply #5

blauwfilms

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@maru Ah Thank you very much! That changes everything hahah!

2024-03-29, 16:30:32
Reply #6

Beanzvision

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Another workflow might be to use a distance shader in a volumetric mat for "ground hugging" clouds and another for atmos. Although this isn't accurate, i'm still getting a decent reflection through the clouds.

Bengamin Jerrems l chaos-corona.com
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2024-04-02, 22:27:35
Reply #7

blauwfilms

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@Beanzvision Late reply, but oh! That's also a cool approach. Hadn't considered using this method but I have some other use-cases where this could be cool.
I've now used the IOR set to 1.0 method and that worked :)

The next step for me will be to make separate cut-outs of the cloud-map for different clouds that should sit at different heights.
It'll take some time as the texture map is 43K, but then the clouds can be stacked at different heights for higher realism.

I've also attached an image of what the latest update looks like without clouds.
Just the atmosphere volume and a new land+water shader.

2024-04-12, 16:40:42
Reply #8

blauwfilms

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@Beanzvision We have made all the Resources on our website available for Free :)
If you would like to download the Earth Digital setup you can do that here:
https://www.blauwfilms.com/product/earth-digital

2024-04-12, 17:18:15
Reply #9

Beanzvision

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Damn Leo, that's epic. Perfect timing to play with it on the weekend! Thank you kindly :)
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