In this exercise, you create a flat roof using the footprint of the exterior walls and a sloped roof with an overhang at the entry. In this exercise, you create a mezzanine in the store room area of the building. In this exercise, you add a toposurface and a building pad to the building site. Part 3: Create a Terrain and Building Pad.In this exercise, you work on different levels to add exterior walls, interior walls and a corridor to the project. In this exercise, you start a project and create levels for the foundation, store floor, upper and lower parapets of the building model. Part 1: Create a Project and Add Levels.