Google SketchUp 3D – Energy Design Plugin
« The Energy Design Plugin was created by the National Renewable Energy Laboratory for the U.S. Department of Energy.
Designed to integrate seamlessly with the SketchUp environment, the plugin allows you to use the standard SketchUp tools to create and edit EnergyPlus zones and surfaces. You can explore your EnergyPlus input files by using all of the native SketchUp 3D capabilities to view the geometry from any vantage point, apply different rendering styles, and perform accurate shadowing studies. The plugin allows you to mix EnergyPlus simulation content with decorative content such as background images, landscaping, people, and architectural finish details—all within the same SketchUp model. »
(Source: Yves Jean-Philippe)