I checked a gtl project into the sandbox so that I can keep postings to the list more brief while allowing people to see the up to date and correctly compiling state of the re-design and re-implementation of the library interfaces. The main header file is gtl.h, which includes the others and defines free functions that may rely on any of the geometry concepts when instantiating the template function. A recent change is to the design is that rather than using SFINAE to overload a free function on return type I now call a meta-function that looks up from the related concept and provides the correct return type based upon the args given (see get() in gtl.h). This eliminates the need to register the return type in a specialized traits class since the concept can provide it for the given type generically. Log: initial checkin Added: sandbox/gtl/ sandbox/gtl/boost/ sandbox/gtl/gtl/ sandbox/gtl/gtl/geometry_traits.h (contents, props changed) sandbox/gtl/gtl/gtl.h (contents, props changed) sandbox/gtl/gtl/interval_concept.h (contents, props changed) sandbox/gtl/gtl/interval_data.h (contents, props changed) sandbox/gtl/gtl/interval_traits.h (contents, props changed) sandbox/gtl/gtl/isotropy.h (contents, props changed) sandbox/gtl/gtl/point_3d_concept.h (contents, props changed) sandbox/gtl/gtl/point_3d_data.h (contents, props changed) sandbox/gtl/gtl/point_3d_traits.h (contents, props changed) sandbox/gtl/gtl/point_concept.h (contents, props changed) sandbox/gtl/gtl/point_data.h (contents, props changed) sandbox/gtl/gtl/point_traits.h (contents, props changed) sandbox/gtl/gtl/polygon_concept.h (contents, props changed) sandbox/gtl/gtl/polygon_data.h (contents, props changed) sandbox/gtl/gtl/polygon_traits.h (contents, props changed) sandbox/gtl/gtl/post_concept_definitions.h (contents, props changed) sandbox/gtl/gtl/post_geometry_traits_definitions.h (contents, props changed) sandbox/gtl/gtl/rectangle_concept.h (contents, props changed) sandbox/gtl/gtl/rectangle_data.h (contents, props changed) sandbox/gtl/gtl/rectangle_traits.h (contents, props changed) The code in the sandbox is intended to conform to boost standards. Feel free to point out instances where I may have failed to do so. Thanks, Luke