Extract centerline curves in two disconnected branches

[ruili]

I see. Thanks a lot! My understanding based on some tutorial videos on youtube is that by deactivating a control point (toggle select it and make it appear blue), you are specifying it as the inlet of flow, so the centerline tree will grow from there. If no endpoint is deactivated, then the first point in this fudicial point list will be used as the inlet. However, as in my case the first point is actually ‘F-1’ which is at the top, it did not make sense to grow the tree from there based on the real physiology, so in the end I only kept ‘final_endpoints-15’ as in the inlet, and I can then do some postprocessing to remove C(18) to only keep the centerline curves in the two branches.