How to get boundary edges from STL file?

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#1

Hi everyone,

I’m trying to get boundaries from STL model.

I’ve tried the following method with converting stl to vtk, it works, but maybe there’s something more convenient?

mesh = meshio.Mesh.read(
"motor.stl",  
file_format="stl",)

mesh.write("motorMesh.vtk")

part = vtk.vtkUnstructuredGridReader()
part.SetFileName("motorMesh.vtk")
part.Update()

featureEdges = vtk.vtkExtractEdges()
featureEdges.SetInputConnection(part.GetOutputPort())

featureEdges.Update()

However, it shows all the edges, but not the boundaries.

Also, I don’t know how to use vtkExtractEdges() to get some data about the edges. Is there any option to check connected faces using vtkExtractEdges()?

#2

You need to use vtkFeatureEdges filter and BoundaryEdgesOn()

Below is the C++ code to do that

vtkSmartPointer< vtkFeatureEdges > featureEdges = vtkSmartPointer< vtkFeatureEdges >::New();
featureEdges->SetInputConnection(diskSource->GetOutputPort());
featureEdges->BoundaryEdgesOn();
featureEdges->FeatureEdgesOff();
featureEdges->ManifoldEdgesOff();
featureEdges->NonManifoldEdgesOff();
featureEdges->Update();

#3

Also, to save a step, VTK has a native STL reader:
vtk.vtkSTLReader()