How to use VMTK split the vessel tree's branch?

[RayCui]

What’s the difference of vtkvmtkPolyDataNetworkExtraction() and vtkvmtkPolyDataCenterlines() ?
I find that:

1. speed. The vtkvmtkPolyDataNetworkExtraction() is faster than vtkvmtkPolyDataCenterlines() , and sametime, the number of points in centerline network is less than in centerline polydata. Does vtkvmtkPolyDataNetworkExtraction() only contain the endpoints of each line？How can I resample the centerline network(vtkPolyData) to get the centerline volume that’s size is consistent with the original mask?

2. accuracy. vtkvmtkPolyDataNetworkExtraction() seems to be less accurate than vtkvmtkPolyDataCenterlines() in blood vessels. But the vtkvmtkPolyDataCenterlines() can easily get the flying centerlines(out of vessel) on small blood veesels. So, I prefer the vtkvmtkPolyDataNetworkExtraction().

flying centerlines example from How to obtain the complete center lines using VMTK?