Floorplanner - Floor plan interior design software. Design your house, home, room, apartment, kitchen, bathroom, bedroom, office or classroom online for free or sell real estate better with interactive 2D and 3D floorplans.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.
roomeon - Roomeon is simply a best in the class interior designing and decorating software that offers the 3D based designing features and functions to its users.
SketchUp - 3D for Everyone
Sweet Home 3D - Sweet Home 3D is a free interior design application that helps to draw the plan of house, arrange furniture on it and visit the results in 3D.
FreeCAD - An open-source parametric 3D modeler