I’m working with a simple emissive material (vector3 multiplied by constant parameter). According to 4.27 documentation, in order to not make a mesh with emissive material contribute lighting to other objects, a person can switch off the “Use Emissive for Static Lighting” checkbox for that object.
However, when I tried doing it in UE5.03, it doesn’t work. The Material is still contributing light to surroundings. I’m wondering if this is a bug, or I did something wrong.
I’m using realtime lighting setup (not baked lighting) with Lumen enabled in project settings (I tried the other option Screen Space) as well, to see if its related to Lumen.
Yeah, I’m trying other things as well. I tried that tickbox as well, and few other settings as well. I even tried this shader setup, when my previous one didn’t work. Extra info:
I don’t want to use custom stencil, because first of all its time consuming if done for multiple objects
I looked at documentation page as well, and its not updated for UE5 for this specifically
Watched a bunch of tutorial on youtube, all of them teach how to turn it on, but none has turning it off, when using realtime lighting/lumen/ue5.
hmm, I’m not in a rush, so partly I do want to know if this is actually a bug or limitation
Using it on translucent is not really an option, because most of my practical use cases for this require 100% opacity. However, this translucent version may come in handy.
After playing around with it a bit more, it seems to be something not just related to Lumen, but Global Illumination, because I tried setting it to screen space (beta) as well, where it gave the same result. However as soon as I turned it off (none)… I get something close to what I need (see pic) … but it essentially effects everything else as well, which makes it unusable solution as well. But definitely it appears to be related to Global Illumination imho now.
Going further in, it seems it is indeed related to ScreenTraces. We might be looking at the wrong cvar (the one you mentioned) …
instead of turning off GI, I set it back to Lumen, and in Show>>Lumen … turned off Screen Traces. So in my editor viewport only… I can see the expected behavior again. However I’m not sure, how it effects the rest of the scene (meaning what is the tradeoff here)
