U.S. Patent No. 6,628,279 B1
United States Patent No. 6,628,279 B1, “System and Method for Three-Dimensional Modeling” by Brad Schell, Joe L. Esch, and John E. Ulmer. September 30th, 2003. The patent for SketchUp, as an instructional video for the modeling of “House1.skp” and “House2.skp”.
Imagery source: United States Patent and Trademark Office