Building design, also called architectural design, refers to the broadly based architectural, engineering and technical applications to the design of buildings. All building projects require the services of a building designer, typically a licensed architect. Smaller, less complicated projects often do not require a licensed professional, and the design of such projects is often undertaken by building designers, draftspersons, interior designers (for interior fit-outs or renovations), or contractors. Larger, more complex building projects require the services of many professionals trained in specialist disciplines, usually coordinated by an architect.