Here you can see how the Rebuild step helps.

The original surface/surface intersection curve has a control point structure that looks like this:



It tends to be fairly dense with control points, and worse yet it made a kind of nasty little extra segment where it crossed the seam, that little extra segment is probably the biggest problem.

Now look at what the curve control points look like after running Rebuild with a tolerance of 0.01 units:



It's basically redrawn that curve but with a much more even control point spacing also unifying those little nasty segment parts. So it's actually a much cleaner curve for using for the next step.


- Michael