Hello.
It seems to me that those are spaces above the lightning fixtures which are offside the light region.
Inside those lightning fixtures families probably you`re gonna see the lightning origin, an yellow symbol. If you select these symbol, you can define the origin of the light and the type of light direction (spherical, hemispherical, dot etc).
So, those black spaces on your model only gonna be lightned if these region reaches there.
If your problem has been solved, please click on Accept as Solution. Then others users can take benefit of it.
Regards,
Felipe Góes
Autodesk Instructor
