Geometry Errors in General Discussion Posted August 1, 2016 Raymond, I initially had your thoughts, and I think we are 99% in agreement, except that there is an object type you don't mention germane to the question - the "Oval." Unlike an ellipse, the oval does not have a consensus mathematical definition, so I think it is telling that VW does not call their object an "Ellipse." What the VW "Oval" is I couldn't really say, and it may in mathematical definition be a bezier curve. So the fact that an Oval when trimmed becomes a series of polylines may not really represent a change of geometry. Donald, you originally raised this question, do you find that a line snapped to the oval becomes different in length when snapped to the trimmed curves? Zoomer, funny! I assume you are tongue in cheek. Seriously, though, are we really moving to a design world in which forms which have been commonplace since the Renaissance are now to be shoved aside by the dictates of CAD engineers? That goes so much beyond the current discussion on precision it belongs in a different thread, but it's a big question, who is leading the development of CAD - designers or coders or marketers? PS: I did the test. In my instance, I created a 3" line snapped to an oval. After trimming the oval, resulting in a polyline curve, and snapping the same line to that curve, it was shorter by 0.002248". This may have to do with the mathematical definition of a Bezier curve, which I don't have a completely firm grasp on despite having at least attempted to read Bezier's book. In my limited view, if you change the endpoint of a Bezier you may be unable to get the same shape regardless of how you tweak the Bezier parameters. Anyone know if this is true? Sorry about the edits changing this post, that's the way the thought process works for me: on the other hand, if the "Oval" as defined by VW is in fact mathematically an ellipse, which has an equation defining every point, then there is no excuse for a clipped portion of that curve being mathematically different from the unclipped shape.