Hi Peiming,
I made a mesh splitter a while back and could adapt that to this kind of work, but it would take some time to fix (maybe during the easter, hope that is fast enough)
In the meantime, did you download my tool TerrainMesh?
That combined with the script I sent you + CullDegeneratedMeshFaces + ReduceMesh should give you the result you got from me. And then you can split the curves BEFORE you mesh them and thus not need to split the mesh… (As a workaround until I combine the tools)
You can download the latest WIP of TerrainMesh here:
New: TerrainMesh plugin (in alpha/beta)’