...plane and a circle (or arc of circle) - new command for construction the intersection between a plane and a sphere Regards, Nicolas -------- Nicolas Van Labeke Research Fellow School of Computer Science and Information Systems Birkbeck College - University of London London Knowledge Lab 23-29 Emerald Str London WC1N 3QS phone: +44 (0) 20 7763 2103 email: nicolas@dcs.bbk.ac.uk