如何使用 python vtk 将剪辑的 object 保存到 stl

Question

I was following clipDataSetWithPolyData

I want to save the clipped square into stl file.

It seems that if I use the stl writter to write it out

clipperOutsideMapper = vtkDataSetMapper()
clipperOutsideMapper.SetInputConnection(clipper.GetOutputPort(1))
clipperOutsideMapper.ScalarVisibilityOff()
# use stl writer to write clipped cube into stl file
stlWriter = vtkSTLWriter()
stlWriter.SetFileName("clippedSqure.stl")
stlWriter.SetInputConnection(clipper.GetOutputPort(1))
stlWriter.Write()

It always returns me this error. I mean it can render the clipped cube in the rendered window but why it cannot be saved?

2023-01-29 17:43:08.985 (   5.569s) [          22AD7D]vtkDemandDrivenPipeline:760    ERR| vtkCompositeDataPipeline (0x7fad6c4bb220): Input for connection index 0 on input port index 0 for algorithm vtkSTLWriter(0x7fad6c4bac80) is of type vtkUnstructuredGrid, but a vtkPolyData is required.
2023-01-29 17:43:08.985 (   5.569s) [          22AD7D]vtkDemandDrivenPipeline:760    ERR| vtkCompositeDataPipeline (0x7fad6c4bb220): Input for connection index 0 on input port index 0 for algorithm vtkSTLWriter(0x7fad6c4bac80) is of type vtkUnstructuredGrid, but a vtkPolyData is required.

Answer 1

I figure it out myself. The issue was stl writter was asking for a vtkPolyData , however only vtkUnstructuredGrid was provided. Thus, we need to transfer from vtkUnstructuredGrid to vtkPolyData by using the following code wrote by myself.

stlFilter = vtkDataSetSurfaceFilter()
stlFilter.SetInputConnection(clipper.GetOutputPort(1))
stlFilter.Update()

Then you just write stl file now:

stlWriter = vtkSTLWriter()
stlWriter.SetFileName("clippedSqure.stl")
stlWriter.SetInputConnection(stlFilter.GetOutputPort())
stlWriter.Write()

Hope it helps everybody who has similar problems.