Hello, In the BoostCon paper you make a benchmark with, among others, the Boolean operations of CGAL, the Computational Geometry Algorithms Library. Which of the following two packages did you use: - http://www.cgal.org/Manual/beta/doc_html/cgal_manual/Boolean_set_operations_... - http://www.cgal.org/Manual/beta/doc_html/cgal_manual/Nef_2/Chapter_main.html I would be glad to check your claim that CGAL failed on one of your data sets. Are your benchmark testdrivers for the various libs under the boost svn, or can you post them, or send them in a private mail. Also I am wondering if I get it right, that you always operate on integer coordinates of bounded size? Do you give any guarantees on topolgical correctness when you snap round intersection points to grid points. best regards, andreas fabri