Did anybody notice a different behavior of Lighting Channels after the release of UE5 (5th of April 2022) ?
Example 1:
-Any light type: Light set to Channel 0.
-Actor/Skeletal Mesh: Character set to Channel 1.
-Static mesh: Set/Bg Small set to Channel 0.
Result >> Set/Bg (Channel 0) gets light from Light (Channel 0) but is shadowed by Character (Channle 1)
Example 2:
-Any light type: Light set to Channel 1. (outside the Room)
-Actor/Skeletal Mesh: Character set to Channel 1. (inside the Room)
-Static mesh: Set/Bg (Small Room, walls, ground and roof) set to Channel 0.
Result >> Set/Bg (Channel 0) Does not get light from Light (Channel 1) but cast shadow over Character (Channel 1), character lighting get shadowed by Set/Bg set to channel 0.
Ideally, for example, Lights (Channel 1) will only light and shadow Objects (Channel 1), would never be casting shadows from objects that are set to Channel 0. Right ???
Did I miss something ? Any new way to set up this?
*It would be great to have some control of the shadow caster, but if any object is gonna cast shadow no matter the channel it is set to… I do really prefer things the way they were before.
Well, I continued digging to see if I could find what was going on here.
Maybe I did miss it somewhere in the UE5 Lumen Documentation, or this is just a normal behavior when using Raytracing.
In any case, here a quick video that demos what is going on:
I was thinking to do some screenshot to help this little description but it has been more easy to add a checkbox with its function to my WIP Lookdev Tool and just record a quick video to showcase what is going on, for those like me, that could be “confused” about what is going on with these lighting channels.
Basically, Ray Traced Shadows ON will cast shadow from the “Channel 1” Objects over “0 Channel” Objects. (and also will make Volumetric shadows not to work) even if it is set only to affect “Channel 0”.
I do love this new Lumen, also because it has been made in a way that does not need Raytracing Hardware to function in a decent way. I hope EPIC can continue improving this and hopefully bring us back the Lighting Channels the way they behave with no raytrace shadows, but… with raytraced ones ^_^.
*Featuring Allen Grippin´s - Great “Cthulhu” Model
Special thanks to him for letting me showcase his model in the future promos of my tool.
Thanks for posting this, I’ve spent a couple of hours trying to debug my lighting setup because I’m having a similar issue. My character is on Lighting channel 0 and is lit with lights in Channel 0. I want to have special control over my character’s shadow and I have a dedicated shadow-casting mesh that’s hidden in game (with hidden shadows on). The shadow-casting mesh is lit with a shadow-casting light on Lighting channel 1. My background is set to receive shadows from both channels.
However, this doesn’t work with the current Lumen/Raytracing lights.
