In past years, the delineation between architecture and interior design was much clearer. As building technology advances and design becomes more technical and specialized, today's interior designer takes on roles that increasingly were limited to architects. Today's interior designer learns about accessibility codes, building systems, and sustainability. Interior architecture design deals with the redesign of interior spaces that requires an architect during the design process. Moving structural walls and dealing with plumbing, electrical, and mechanical systems are all part of interior architecture design.