hi, before reinventing the wheel, have you had a look at Tigs http://forums.sketchucation.com/viewtopic.php?t=30846 or sdmitch's http://forums.sketchucation.com/viewtopic.php?t=40172, and I think there's others [in phlatboyz?]... If they don't do what you need they may be modifiable by you or the author or a collaboration [PM the authors] It's a good way to learn the 'ways' of SU ruby... although it still eludes me... john