Hello Presto 423,
I’m sorry I haven’t contacted you for so long. I don’t usually use the forum. I solved the problems. As already said, the problem with the mirroring of objects in blender with Ctrl + M. Objects become one-sided transparent in the UE. After lightbuilding they are black. Maybe not with simple objects like cubes etc., but with relatively complex modeled objects. They have to be rotated manually with R + the corresponding axis + degrees. greetings