I assume you've seen and compared various geometry libraries - in particular CGAL is an excellent cutting edge computational geometry library (in many ways - C++ design techniques, overall functionality, "number kernel" architecture): http://www.cgal.org/ There's dozens of good geometry libraries available, so I think it's essential to have a well-written, focused rationale. Comparisons / contrasts with existing libraries would go a long way towards explaining what this library is trying to accomplish versus other libaries in similar domains. (Myself, I'd love to see a Boost level-of-quality library that supports geospatial concepts - latitude / longitude systems, coordinate reference systems, etc.) If you're aiming towards a Boost style version of Java's awt.geom package, that would be good to know. As already mentioned, efficiency is crucial, since this domain will have applications that create and use millions (or billions) of geometrical objects. So keep abstract base classes to only essentials. Others will have deeper and better recommendations, I'm sure ... :) Cliff