Green Screen Material affected by lighting

[celestia]

I’m trying to create a green screen backdrop for my scene but the material is being affected by the lighting in the scene which is throwing everything off. How do I make the green screen plane not be affected by lighting?

I tried changing the material to unlit but that just turned it black. I just want the green screen plane to be a solid color and not be affected by the lights in the scene

[JoeProgram]

Hi celestia,

There’s a couple options…

OPTION 1 - Lighting Channels

One is to use the “lighting channel.” By default everything is set to 0. If you select your wall and switch it to only use Channel 1 or 2, it’ll ignore your point lights:

We’ve removed the direct effect of the light on the wall…

However, this doesn’t completely turning lighting off on the wall. For example, if I move the light and Mannequin close to the wall, you can see that the light is bouncing off the Manequinn and affecting the wall.

OPTION 2 - Unlit, Emissive Material

I’m guessing your material looks something like this.

And yep, it produces the standard effect.

If you set it to “Unlit” it does turn black. But you can see how the pin for the “Base Color” is now disabled - this Shading model isn’t using that pin.

You can switch it to “Emissive Color.”

That takes care of the lighting on the greenscreen, but creates a new problem…

The greenscreen’s emission is now emitting onto the other geometry

Depending on your needs, one option to get around this is to set it as the material of your SkySphere. Get rid of all the other things affecting the sky, and just set the SkySphere’s material to your new unlit green material.

We now have a lit character, with a background that’s a solid color and doesn’t turn the remaining geometry green.

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I’m sure there are other ways to do this, but perhaps one of these two simple options will work for your use case?

Hope this helps, and good luck on your project!

[celestia]

Thanks for the detailed explanation. The lighting channel helps with blocking some lights in my scene such as the HDRI and directional lights but for some reason it does not help block out the rect lights in the scene which are lighting up my room and character. Even putting those lights on separate channels from the backdrop I can still see the light on the green screen.

I have not tried the other method yet

[celestia]

I’m a little lost on what you mean by “set it as the material of your SkySphere” since I’m not using a skysphere in my scene.

As for the lighting channels method it seems like changing the green screen to a separate lighting channel does prevent the direct light from showing on it but as you said the lights still bounce off the walls in my room and my character. Not sure what to do here

[JoeProgram]

If you’d like to try the SkySphere solution, here’s the workflow for finding it in the Unreal 5.1:

Select File > New Level > Basic

The SM_SkySphere is one of the default assets.

I’m not sure if it’s in other versions of the Unreal Engine, and whether the setup would work for you may depend on the details of your project.

[JoeProgram]

Hm… I found a thread where another two people had the same conversation, and came up with the same answers

[JoeProgram]

Oh, actually, on both that thread and the bottom of this one, they say setting the material’s “Blend Mode” to Translucent stops the emissive effect…

For comparison…

With Blend Mode set to Opaque

With Blend Mode set to Translucent

Geometry fully removed

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Doesn’t look like Translucent 100% removes the emission, but it is much subtler. Maybe good enough?

[celestia]

The missing piece was setting the blend mode to translucent. Now it works perfectly without shadows. Thank you so much, you’re a lifesaver