[tbd]

1. Ok. You have made a spaceship or whatever, and want to make a cocpit. Well, this is how I do it.

2. Select the surfaces you want as your cocpitglas and do a "cut away object" on it.

3. Now put a chair in there so you have something in the cocpit. And hide the glas when your done.

4. Select the vertices in the front of the cutout. This may be easier in wireframe mode. Change between 3d view and sideview to get all the vertices.

5. Extrude edges.