I have done some research in the mean time and found these 2 links:
https://www.reddit.com/r/rhino/comments/83v78o/how_do_i_convert_from_geometry_to_brep/?rdt=51463
However these methods apply to former versions of Rhino and Ladybug. I’m using Rhino 8 and Ladybug 1.7.0. Does anybody know how I can perform a direct sun hour calculation on an imported file from Google SketchUp?