Reference : Why CAD Surface Geometry is Inexact
Incremental progression along the intersection curve.
This method use starting points on the intersection curve to obtain new points evaluating the tangent direction of the curve.
search for starting points for every intersection curve，can use the subdivision method.
The marching process first-order ordinary differential equations
The numerical intersection algorithms introduce gaps and openings at the best-fit curves representing the intersections, making the resulting surfaces non-watertight.