Curved Surfaces are special, native objects in Shade – and one of the features that has differentiated it from day one. But what are Curved Surfaces? Lets answer that question by first looking at Curved Lines.A Curved Line is a native Shade line object. Curved Lines are effectively one or more bezier curves. Bezier curves are parametric curved lines – they are calculated curves between points. Consider drawing a line, with a point at the beginning (A), the middle (B) and the end (C).
Just parallel to each of these points is a handle, and it extends in each direction from the point.
If you pull up on the first handle of point A, then the direction of the line in front of it is pushed down. If you were to do the opposite – pull up on the other side of the first handle, it would bulge the line between it and the next point.
Each adjustment of the handle creates a curve. Make adjustments of the other handles and you end up with multiple curves in a line. What makes this a wonderful thing is that its all expressed in a way that has nothing to do with resolution. No matter how close or far away you are from this curved line, the math behind the line ensures that its always perfect – and always curved.
Compare that with a polygon mesh. A polygon mesh is made up of points and lines, however every angle is predetermined. Adding more vertices can give the illusion of smoothness, but the closer you get, the more you realize you still have obvious angles.
NOTE: Shade 3D has a native smoothing capability that can smooth the appearance of polygon objects, without changing the actual polygons themselves.
If your model is made up of curved lines though, the close you get to the object, the smoothness and angles remain pure.