This 3D model was originally created with Sketchup 13 and then converted to all other 3D formats. Native format is .skp 3dsmax scene is 3ds Max 2016 version, rendered with Vray 3.00 Here is something that you might be able to use. It is a component, so all you would have to do is import it into your model. To change, either explode it, ot edit it. The windows on the top are open somewhat. Used follow me to make the glass panels as well as define the ribs. The intersection of the ribs on top are conjectural. Put it this way, it looks logical. You could add a door for a greenhouse also. Bob