Thanks for purchasing my extension.
Yes, you 're right, the main concept is creation a “graphic overlay” over model. This overlay shows the information which has been extracted from model without touching them per scene.
This method can be between SketchUp model and LayOut, this not only helps us more information when presenting the model with SketchUp Viewer (for example), but also more speed and control in display annotations when making Construction Documents in LayOut.
The extension had a fully user manual and ability to customize almost annotations or Curic Section template according to every workflow. If you had any question, please let me know.