Freemium 3DTIN is an online 3D-modeling tool that allows you to render designs as intricate as the Taj Mahal or playful as Super Mario. The feature set more closely mirrors Google SketchUp than the costlier AutoCAD (or SketchUp Pro) but designs can be exported in a variety of formats if you want to use another modeling tool. In true open-source fashion, all functionality (including saving to the cloud) is provided absolutely free-of-charge with the caveat that designs are shared under Creative Commons; a premium account gets you private cloud space. A word of caution to Internet Explorer and Safari users: 3DTin requires Google Chrome or Mozilla Firefox with WebGL support.
