progeCAD - progeCAD is DWG/DXF-native CAD software, built for professional drafting.
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.
BricsCAD - A powerful CAD platform, with features familiar to you from native .dwg applications.
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.
MicroSurvey Software - MicroSurvey CAD is a full-featured CAD package that lets you do everything from creating point clouds to designing complex survey networks.
SketchUp - 3D for Everyone