Volumetrics in Physical Material cuts out reflect underneath

[blauwfilms]

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

[maru]

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)

[blauwfilms]

@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?

[blauwfilms]

@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 :)

[maru]

You can create a Corona Volume Mtl with displacement this way. :)

[blauwfilms]

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

[Beanzvision]

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.

[blauwfilms]

@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.

[blauwfilms]

@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

[Beanzvision]

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

[Nejc Kilar]

Thank you for making this available to everyone, I too can't wait to play around with it :)

[steppes]

thank you for that!

But: when it comes to realism, we do not need any displacement or bump oder normal on an earth model. The earth ist perfectly flat. A Billiard ball used for the world cup is allowed to have more displacement oder bump, than the earth in fact has!

[blauwfilms]

Thank you everyone! I'm happy to hear all of this :)

And @steppes, wow... I looked this up and went down a rabbit-hole of the relative size of the Earth.
Very good point. Thanks. I was honestly already feeling that the Earth was "feeling small" with the Displacement turned on.
The scale felt off.

[steppes]

but do not use displacement für the rabbit hole! ;)

But for this you do not need a rabbit hole. It is pretty simple: Earth diameter is about 12750km, the max height difference on earth between mount everest (+9km) and marianna trench (-11km) is 20km. 20km out of 12750km is about 0,16%. Since you can see the water, maraianna trench is out of equasion. The result is 0,07%.