vtkMultiPieceDataSet保存UnstructuredGrid数据并输出vtm的python代码

以下是保存UnstructuredGrid数据为vtm文件的Python代码：

import vtk

# 创建一个UnstructuredGrid数据集
ugrid = vtk.vtkUnstructuredGrid()

# 添加节点坐标
points = vtk.vtkPoints()
points.InsertNextPoint(0, 0, 0)
points.InsertNextPoint(1, 0, 0)
points.InsertNextPoint(0, 1, 0)
points.InsertNextPoint(0, 0, 1)
ugrid.SetPoints(points)

# 添加单元格
tetra = vtk.vtkTetra()
tetra.GetPointIds().SetId(0, 0)
tetra.GetPointIds().SetId(1, 1)
tetra.GetPointIds().SetId(2, 2)
tetra.GetPointIds().SetId(3, 3)
ugrid.InsertNextCell(tetra.GetCellType(), tetra.GetPointIds())

# 创建MultiPiece数据集
mpd = vtk.vtkMultiPieceDataSet()
mpd.SetNumberOfPieces(1)
mpd.SetPiece(0, ugrid)

# 创建vtm数据集
vtm = vtk.vtkXMLMultiPieceDataSetWriter()
vtm.SetFileName("unstructured.vtm")
vtm.SetInputData(mpd)
vtm.Write()

以上代码将创建一个包含一个UnstructuredGrid数据集的MultiPiece数据集，并将其保存为vtm文件。您可以根据需要修改代码以适应您的数据集