Frenchy, the difference is not just artistic. The main difference is curvature continuity. The tangent arc show an abrupt change of curvature where it neets the line. When this is translated to surfaces and rendered, there is a distinct visual line at the meeting point. This is called G1 tangent continuity. To avoid that artifact, G2 or G2 curvature continuity is needed. That's what the blend does. The curvature along the blend is not continuous as it goes from 0 to 0 at either end, and does it smoothly. This is the sort of continuity you need for surfacing things like a car body or the back of an I-Pad (Jason Ive, the designer at Apple, forbids the use of G1 anywhere in an Apple product).
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