The Graphisoft MEP Modeler (where MEP stands for Mechanical/Electrical/Plumbing) is an extension to ArchiCAD, Graphisoft's architectural design tool to create three-dimensional models of ductwork, piping and electrical networks in order to make the building information model of the designed building more detailed an accurate. Since ArchiCAD is primarily used by architects, the building parts which are usually modeled in 3D with ArchiCAD are walls, columns, slabs, roofs, etc.