A modular assembly capable of converting from a shipping container configuration into a building unit, and from a building unit into a shipping container configuration. From the shipping container configuration, a plurality of frame panels and unit panels moveably connected to a frame of the modular assembly are selectively positioned to form the floors, walls, and ceilings of the building unit configuration thereby forming a living and/or commercial structure complete with electrical, water and sewage connections. The assembly may include an automated erection system, which may include a system of electric motors, gears, pulleys, cables, automated mechanical arms and electronic controls, located within the container structure of the modular assembly, and which interact with a plurality of frame panels and unit panels to deploy and retract the plurality of frame panels and unit panels for constructing the shipping container configuration and building unit configuration.