[lisa]

Visualize the revolve tool as a lathe. If you do not want a hole in the object, bring the polyline all the way to the center axis before you revolve. Likewise, to give the cup thickness, draw the outline of what you want before you revolve it.

For a house interior, add polygons to the inside to make the interior. AC3D is a polygon modeler not a solid modeler, which means there is no concept of "solid" or "hollow". It's all just surfaces. The extrude tool is a good way to add thickness to a flat surface for something like a wall.