<HTML><BODY>Dear Berk,<br><br>Thank you for the reply. I was trying to use the Python Calculator. I created a plane source, but I do not know how to put it into projection calculation. The idea was to use one normal vector to find dislacement vectors projections in a plane. How to create a threshold I have no idea at all. May be you could provide some more reference.<br><br>Faithfully yours,<br>Oksana<br></BODY></HTML>