Architects often use physical models of proposed developments to get the idea and concept across to various stakeholders including investors, planning departments and local residents. These models though are usually supplemented by a 3D model shown on screen with a video made directly from CAD files though. The reason for this is simply that though a 3D model takes a lot of time and expense to be made by usually a rapid prototyping service the level of detail is always limited and to really get the idea across and allow the detail of a design to be seen it needs to be shown on screen.The 3D CAD files though already exist for these developments and contain all the detail needed and this combined with the latest 3D printers used by rapid prototyping service companies means that highly accurate models can now be printed directly from these files.