Michael, I assume you are talking about 2D polygons...
Just take a 3D cross product of the first two vector (P3 - P2) x (P2 - P1). If the resultant vector is coming out of the screen (Z < 0) then the polygon is counter-clockwise. If it is going into the screen (Z > 0) then the polygon is clockwise. http://chortle.ccsu.edu/VectorLessons/vch12/vch12_1.html That page may be of help if you don't know what the cross product is. Note: to do the 3D cross product, just use Z=0 for all the points. HTH, Jeff M. On Wed, Feb 3, 2010 at 3:03 AM, Michael Kristensen < [email protected]> wrote: > HI THERE > > Can you figure a smart way to check if the flow of a polygon goes clockwise > or counter-clockwise? > > > Thanks > Michael > _______________________________________________ > use-revolution mailing list > [email protected] > Please visit this url to subscribe, unsubscribe and manage your > subscription preferences: > http://lists.runrev.com/mailman/listinfo/use-revolution > _______________________________________________ use-revolution mailing list [email protected] Please visit this url to subscribe, unsubscribe and manage your subscription preferences: http://lists.runrev.com/mailman/listinfo/use-revolution
