Geometry Errors in General Discussion Posted August 4, 2016 Raymond, after talking with you and testing, I have discovered the source of my error, which causes us even more distress if we are concerned about accuracy and the integrity of the CAD calculation engine. I now agree that the VW "Oval" must be a true ellipse, and is probably generated from the algebraic ellipse equation ((x/a)^2 + (y/b)^2 = 1). First, here was the source of my error, and without talking to Ray I would never have guessed. In my attempt to cause the calculation engine to reveal its secrets, I used two methods interchangeably: the join tool, whereby the program calculated the intersection between a line and a curve, and a snapping method, whereby I extended a line beyond the curve, and dragged it back to the "object/object" snap cursor. It turns out that those two methods give different results!! I believe in the case of an "Oval" that the "object/object" snap point does not actually lie on the oval curve (the difference in my test situation on a 2" wide oval was about 0.0003" - which could amount to feet on a large site oval). I also verified Ray's method by calculating the coordinates of two random points on the ellipse (using the formula above) and placing loci there, and discovered that they exactly coincide. I tested the coincidence by creating a 1.0000000000" line horizontally from the locus, then joined that line to the oval, resulting in exactly the same length to 10 decimal places, the limits of VW accuracy.