CAD, BIM & 3D

At http://www.suplugins.com/index.php you can find information and an evaluation version of a rendering plugin for SketchUp. It's not free and for Windows only (at the moment), but has very little setup, so it might just be what you want.

At http://www.gvsig.gva.es you can find more info (also in English, if you click the right flag). gvSIG is a tool oriented to manage geographic information. It is characterized by a user-friendly interface, with a quick access to the most usual raster and vector formats. In the same view it includes local as well as remote data through a WMS or WFS source. Available as both binaries and source-code, for Windows, Linux and OSX.