Ecdesign - Ecdesign.
FreeCAD - An open-source parametric 3D modeler
Studio Designer - Studio Designer is totally different from the traditional designing and home decorating programs.
SketchUp - 3D for Everyone
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
LibreCAD - An open source 2D CAD application for Windows, Apple and Linux.