This tool is not currently released and this documentation exists to outline how to use it ahead of it's release.
What is the Model Builder?
Lucas' Simpsons Hit & Run Model Builder is a tool that allows you to build maps, cars and state props for The Simpsons: Hit & Run.
This is a command line tool that is powered by XML Rules files that define input files and how to output their contents.
The tool includes a large array of base rules as well as special components for use in Input SketchUp Models.
Power users are able to modify the included rule sets to their heart's desire but it's important to keep in mind that this documentation assumes that you are using the stock rules.