( solved :D) I have imported a city from osm. Do it like :
https://www.youtube.com/watch?v=NW_djQS_N8U
Now I tried to add a texture to my city walls. But it doesnt work. Someone has any Idea? I add the picture to Base Color. Then I dont know...
Here is the link to the blender file: including the walls
its no big thing I want to do .. just put the texture onto the wall.