[Fetaure Request] Validate statc meshes before light building


Here is another nice to have feature (request):
Before Lightmass actually starts building the lighting, it would be nice if the engine could just make a pass over all static meshes and checks for overlapping UVs and other issues.
Its a bit stupid to wait an eternity for Lightmass to finish, only to be notified that one mesh has overlapping UVs.
Sometimes the LighmassCoordinate Index is just set accidentially set wrong. But still, you have to do the light build allover again.

I would prefer in this case if the engine just pops up a dialog and says “Object xx has overlapping UVs. Do you still want to build the lighting?”
Or even flag it in the content browser (like it is marked for collisions)


It gives you the warning on import of the mesh in the first place, why bulk up the process of warning you again?

It does not in all cases. Consider the following:
You create mesh in max with 2 UVWUnwrap modifiers. The first one for the textures is overlapping and the second, for the lightmap is not.
However, by accident, you leave the map channel in the second modifier set to 1, efrectively only having one UV channel.
After you discover your mistake, you change the modifier channel in max, export, reimport in UE4, but the channel will stay set to 0 there.
If that gets overlooked, you only are only notified on light builds…
On reimporting, you dont get any warnings at all. I also didnt get any warning when I imported themesh in the first place…

Hi -

There is a feature request to add this feature, UE-814

Thank You


While this doesn’t address the issue of checking before building lighting, there is an automated test in place to check Static Mesh UVs. If you open up the Session Frontend (Window > Developer Tools > Session Frontend), and search for Static Mesh UVs Check in the Automation tab and run the test, it’ll load up and check every mesh in the project (fair warning: it can be pretty slow).