How to achieve no indirect lighting in the dark side of planets in the sky?

Development Rendering
1

Hi everyone,

I’m new to UE and this is my first post here, I hope I’m not making any mistake. Thanks for your patience.

I would like to place a moon or planet in the sky. I started by doing it like I did in other tools, i.e. create a big sphere and make it really big (around 20 million UE units) and put it really far.

The problem is the indirect lighting in its dark side, which I can’t seem to avoid unless I make the sky light zero (which of course I don’t want to do because it ruins the look of the rest of the scene).

A moon or planet shouldn’t have any light in the dark side, so I want to cancel it completely. In my usual application (e-on’s Vue) that’s just one checkbox in the material (“ignore indirect lighting”).
In UE, I tried fiddling with the material, tweaking a lightmass volume specifically for the moon, I tried a post process volume just around the planet and changing its settings, etc. Whatever I do, I can’t get rid of the indirect lighting. Can someone please help? Thanks a lot!

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2

This essentially has to be done using an unlit material, defining the shadowed side using the nodes that SkyAtmosphere provides to the material editor.

You could try with a lit material but you’re going to run into issues.

3

Thank you for your reply. I was hoping for a more straightforward approach, perhaps some setting that I had overlooked. After all, sci-fi scenes made with Unreal with moons and planets are fairly common so I thought this should be directly provided by the engine.
Thanks.