Thanks Chris and Travis!
I now understand that 'complementary cond lines' when two cylindrical prims are back to back is ok. As long as the radius is the same and the shape is convex, each of the cond lines engage "too late" from one side, but accurately from the other, thus together producing the net result of a correct cond line. Works even when the radii are different. Great!
So the issue comes when one of the two surfaces is missing its complementary cond line. E.g. when a quad or triangle is used adjacent to a cyl prim. In this case, one needs to add either a complementary cond line or a cond line with accurate control points.
Now consider the case where one cyl prim is convex and the other concave. In this case, both cond lines engage too early. The cond line isn't needed at all if the radii are the same. Apparently, this scenario will need to be avoided.
cond3.png (Size: 6.46 KB / Downloads: 21)
I now understand that 'complementary cond lines' when two cylindrical prims are back to back is ok. As long as the radius is the same and the shape is convex, each of the cond lines engage "too late" from one side, but accurately from the other, thus together producing the net result of a correct cond line. Works even when the radii are different. Great!
So the issue comes when one of the two surfaces is missing its complementary cond line. E.g. when a quad or triangle is used adjacent to a cyl prim. In this case, one needs to add either a complementary cond line or a cond line with accurate control points.
Now consider the case where one cyl prim is convex and the other concave. In this case, both cond lines engage too early. The cond line isn't needed at all if the radii are the same. Apparently, this scenario will need to be avoided.
cond3.png (Size: 6.46 KB / Downloads: 21)