Descartes 3d modeling from point cloud

Good evening everyone,

I have a similar question , I draw in my bachelor thesis a house from a point cloud .

Problem : Windows

solution 1 : drawing polygon and from this cut out the window , this is possible ? If yes how?


solution 2: drawing instead of one polygon around the window , several faces . Now I havearound the polygons unnice lines . I have chosen this path . 
Can I combine two polygons to one? if yes how?


Full of hope and greetings

Philipp Nicola