Some time ago (in 2004) I implemented Jarvis convex hull algorithm (that's the same thing as "gift-wrapping" in 2D, AFAIK). You can grab the source code from my sources page http://www.camelot.homedns.org/~michalis/sources.php --- download "Kambi's standard units" and look inside for file units/3dgraph/convexhullunit.pas. The working demo of this is in bezier_curves program, see http://www.camelot.homedns.org/~mich...ier_curves.php. Feel free to use and extend this code. (it's licensed on GNU GPL)