Blender Lighting Issues

[Brennen1350]

A couple quick questions regarding UV mapping in blender.

1. When is it necessary for a second UV map?
2. What are some good island margin settings? as close together as possible or do larger margins do something beneficial?
3. Why do my objects look better with pre-baked lighting?
   (The model has two uv images, first is smart unwrapped 1024x1024, second is Lightmap packed 1024x1024)
   Pre Bake
   
   
   
   (Ya, my modeling skills need a bit of work)

Post Bake

4. How do you “reset” or remove faces from a UV map? The reset feature just puts them all in the middle as overlapping circles.
5. Why do faces moved outside of the UV zone still have texture? (it looks very low resolution but is still there, are there any performance implications? or is it low res enough to essentially be null)
   (The bottom of the house’s UV’s are moved outside the UV mapping zone)
   
   

Bonus question: Why did this guy choose a picture of the ****-piece (Male Chicken-piece) over any other image? (I know you were all wondering too :D)
https://forums.unrealengine/showthread.php?29929-My-4K-Textures-look-very-low-Res-in-UE4-but-were-fine-in-UDK-Please-Help!

[anonymous_user_923c79df]

1. complex meshes and when you get a warning after you have build your light -> you always need a lightmap, but when you dont have a 2nd uv channel the UE4 will take the 1st one as the lightmap (and when you have overlapping faces in there, you will need to create a own lightmap)

Here you can get more information:

[Brennen1350]

Well, thank you good sir.

Ironically enough what solved my problems was one of your tutorials that I stumbled upon while googling. I didn’t know you could change margins after initialization in blender. (and that the margins actually change, unlike in the prompt when you create it, where the margin change is about 1 pixel)

Also why are UE4’s lightmap resolutions so small initially? (32) and why doesn’t it just inherit the resolution from the actual map?

Heres the video in case anyone else has a similar issue.

[Tim_Hobson]

It is small to prevent from having everything that is imported be a larger lightmap, especially if it’s not necessary. For instance if you import a small object that really only needs a 16 or 32 lightmap resolution but the default is 256 or 512 this is really overkill for it. It’s better to have to always scale up than to realize you need to go back and scale everything down.

Also, having a good layout for your UVs will allow you to get away with smaller lightmap resolutions around 64 and 128 for moderate sized objects.