Roomtodo - Simple yet powerful online tool for interior design and floorplans with built in walkthrough module.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
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.
Ecdesign - Ecdesign.
Palette CAD - Palette CAD is one of the easiest 3D design software for those people who want to use a simple to use program for interior designs.
autodecco - autodecco is the name of a highly advanced interior design software that is being backed by the advanced AutoCad technology to let the users to save their time and get more and more from this software.