I chose Furniture > Import furniture... menu item to import a 3D model, but during the wizard, I got the message Sweet Home 3D must exit now because of a fatal error in 3D rendering system. What can I do? This is a problem due to the configuration of your graphic card. Please read the answer to the same question in the Installation section. If it doesn't solve your problem, you may also try to import librairies of additional 3D models.