The design of the building is largely based on architectural, engineering and technical letters. All construction projects require the services of a building designer, usually an architect or civil engineer with a degree. Smaller and simpler projects usually do not require a professional and certified person, and the design of these projects is usually under the supervision of a building designer, planner or an interior designer and contractor. But larger and more complex projects require the services of a large number of professionals and trained people under the supervision of an architect.