Inheriting texture from another layer Hej!
It's my first post so sorry if I overlooked something.

I am here to ask how object could inherit texture from another object lying under it. What I mean?

I have a raster image (orthophotomap on Digital Terrain Model) and I imported a shapefile with buildings as polygons (about 5000 objects). I can extrude these buildings with BlenderGIS plugin to exact height, but I 'd like to have on a top surface exact same image as these buildings are overlying - to have a good image of a roof on every building. Side walls can be blank/grey or with stretched image - they are not a point of my interest right now. How can I do it?

Please help.
Thanks in advance!

I attach print-screen to illustrate the problem.
You can join all objects into one, go to edit mode, top ortographic view, select all, press U and choose "Project from view".

Load your image into an UV editor window, adjust the scale until it fits.

Then assigne a material with the image as texture.
You can select all bottom zones (walls) and assign another material to avoid stretching.

Then you can separate all by loose parts (P) if you need to.