Hello adldesigner and thank you very much for your help - that´s really fantastic. My english isn´t really good, so sometimes there are many things I don´t really understand. okay, below you can see a image, that describes some questions I have. I´m really not sure, if I understand definitly what the opossing curves are, and the spans ? If this will fit in my little monkey brain, I hope I can build up the ep-curves as they should be --> consider your lections: 1. Opossing Curves should always have the same spans. 2. Opossing Curves should always have the same direction. puuuhhh, it´s not really easy with me .... thank you soo much for your help, bernhard