Using decals (or similar) to darken an emissive/unlit material?

[AngelitoGamedev]

Finally just got this working. Huge thanks to RhythmScript. There’s an additional post by them here that I also used:

UE5 - How to - player mesh ignore some decals but not others

I saw this exact thread on Reddit actually I have a lot to unpack. It assumes knowledge of editing material attributes for the surface materials, so I deduce I need to figure out how to get into the material editor now and set properties how I need. A tutorial on this would be immensely helpful; when I get my head wrapped around it I will do up a youtube on it. Thank for the reply.

Here’s a super simple setup that worked for me in Unreal 5.3, projecting onto unlit materials:

You have to use the 1x1x1_Box_Pivot_-XYZ static mesh for this, and then you freely scale it to set your bounds. You can find it in .../Engine/Content/Functions/Engine_MaterialFunctions02/SupportFiles/1x1x1_Box_Pivot_-XYZ.uasset

As far as I can tell, this is the only way to project decals onto Unlit materials currently (for projected drop shadows and stuff).