Dear Khadidja, I guess you are using Gate 6.2 (or older versions). The ellipsoid volume is just implemented in Gate 7.0. Hope this helps! Hojjat -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.opengatecollaboration.org/mailman/private/gate-users/attachments/20150228/e5e62786/attachment.html>