Frequent contributor Kent Cooper shares a routine that allows you to offset an ellipse where the result is also a true ellipse. Normally if you offset an ellipse in AutoCAD, the resulting object is a spline. Kent's routine creates an ellipse whose quadrant points are exactly the desired distance away from the equivalent points on the original ellipse. Other points along the new ellipse entity are not necessarily a consistent distance away from the old one, and that is why AutoCAD creates a spline. Start by loading the LISP file, then type in the command OFEL. Kent's code contains lots of comments, and plenty of technical details about how this routine works and why. Good job, Kent. |