What is the construction strategy of traditional surface modeling methods?

There are two construction strategies.

1. The first construction strategy of the traditional surface modeling method is to directly fit the surface patches from the point cloud, and then adjust, intersect, cut and splice all the surface patches to generate the final surface model.

2. The second construction strategy of the traditional surface modeling method is: slicing the point cloud and fitting the characteristic line or interactively constructing a 30-spline curve on the point cloud, and then creating a surface patch corresponding to the feature through an appropriate surface construction method.