So what exactly is SketchUp, and how does it work? In a nutshell, SketchUp is an intuitive 3D modeling program that lends itself to fast visualizations. Think of it as a miniature version of AutoCAD for the non-tech savvy, or more aptly, "the pencil" for architects and urban planners. Certain intricate details need to be left out for the sake of quickness when using SketchUp, but many key architectural components can still be realized.