Construction of the two-story O House residential building, constructed using 3D printing technology, has been completed in the Japanese city of Kizuki. The project was completed by Onocom and Kizuki using a COBOD industrial printer. It is the first two-story building of its kind in Japan to receive official occupancy permits.

The house has a floor area of ​​50 square meters. The foundation is buried 0.5 meters deep, and the building's height above ground reaches 7 meters. The structure is based on a reinforced concrete frame, installed on a strip foundation with piles. The walls, floor, and roof, printed from a cement mixture, are placed within this frame. Some of the elements were manufactured off-site, and the printer was operated by four people.

The house's architecture is inspired by the shape of natural caves: it features curved, arched walls and no vertical windows. Light enters through skylights in the roof. The upper floor houses the kitchen, dining room, and living room, while the lower floor houses a bedroom with a separate bathroom.

The structure complies with strict Japanese earthquake resistance standards. The building was constructed as a demonstration project, with plans to construct similar buildings and use the technology for disaster recovery.