I am a new Unreal user but accustomed with Max, Maya and Blender. (so the correct export with multiple uvs poses no problem)
I currently have a project I’m trying to visualize in Unreal and the lighting is very important. The lightmass baking is kinda ok but I would very much like to use my own unbiased baked lightmap.
I can’t seem to find a way to impose my own lightmaps, specifically the lightmaps I see in the Static Mesh Lighting Info.
I could find workarounds with the material (for instance making the diffuse black and adding the emission) but it throws off the excellent physically based shader and I would need a different material for every object even though they have the same material.
I have some experience in programming but I wouldn’t want to recomplile the whole engine to get what I want. I’m just mentioning in case the answer could be code based.
To actually specify a lightmap inline with the current lighting system isn’t really possible because the lightmaps aren’t really just simple lightmaps in most cases, they are directional lightmaps with some limited directionality. I think it would be very hard to get an image rendered that works. Would require a certain amount of coding.
I can suggest a method that will kind of be halfway in between a complete emissive material and what you want to do. You can use part dynamic lighting part lightmap if you do this. Keep your diffuse how you normally would, and use your 3d software to render out a black and white shadow map. Then you can multiply your diffuse by the shadowmap.
Then you would use a second lightmap with indirect light backed into it in the emissive channel to add the bounce lighting.
First thanks for the answer and sorry for the delay.
I tried it like you said, the only difference is that I baked a diffuse layer forced to grayscale later and the results are not that great. I’ll grab some screens and post them.
The main problem is that it forces me to add a different material for every “lightmap” object as I need to apply different textures. If I accept this constraint I have much better results with 0 diffuse and the baked textures as emission with the rest of the parameters in place. It keeps the very realistic lighting with all the reflection and bump magic the unreal engine has to offer.
I tried to find some reference concerning the directional part of the lightmaps. Are you sure it has a directional component? Do you have a link that mentions it?