How do you exclude a mesh from being lit by a particular light?

Development World Creation
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1

If I remember correctly, UDK allowed you to exclude meshes from lights, so that you could selectively affect meshes with lights. Maybe I’m not remembering that correctly, but I’d like to think that I did. Anyway, the purpose is to attach an ambient light to a first person blueprint. I’d like to exclude the first person mesh from being lit by this light.

2

As far as I am aware this feature is currently not possible in UE4, although it is something that I really hope gets implemented. If Anyone knows otherwise then I too would love to know how to set this up!
Matt

3

Hi,

In UE3 you could set up lighting channels to do what you are describing, but this is not possible with UE4 due to deferred shading.

Thanks!

Tim

4

This would be a high recommended feature. Like in 3ds max, exclude and include objects to a specific lightsource. I have the problem, when I lit the rooms from an apartement from the outside with spotlights (faking daylight on the backside of the building, which has no direct sunlight). I 'll get the ground from the outside also lit a bit, which is total unnatural. So excluding the terrain from the lightsource would be the solution, but not possible. Is there no chance to implement that? This would be awesome!Thanks

5

Lighting channels are not possible with deferred rendering. This feature was even removed from UE3 a while back as well.

The alternatives are finding ways to work within the system and limitations of that system.

If you need different lighting results for interior vs exterior, I would recommend using level streaming and building lighting separately for these levels with static lighting.

You could take a look at this sample project I made that was helping someone on AnswerHub: [TUTORIALS] Photons Be Free: Mini-tutorials and other curiosities - Community & Industry Discussion - Epic Developer Community Forums

This is a demonstration of using different lighting setups for levels occupying the same space. While these are doing a switch of the level, the same process could be used to have the interior on it’s own level that has specifically built lighting and the exterior using it’s own lighting.

I hope this helps.