[vtkusers] Is there a way to check data before using vtkBooleanOperationPolyDataFilter?

[ftouvet]

Hello all,

I would like to use the Intersection operation from
vtkBooleanOperationPolyDataFilter in order to know how much my meshes are
overlapping each other ; so I designed a pipeline to prepare the data and
make it fit to the Filter initial conditions, but it seems that I do miss
something. Do somebody use this filter and know a way to be sure that the
input data are ok?
Here is my code in Python:

source1 = vtk.vtkPolyDataReader()
source1.SetFileName("mesh1.vtk")
source1.Update()
source2 = vtk.vtkPolyDataReader()
source2.SetFileName("mesh2.vtk")
source2.Update()

poly = [source1.GetOutput(), source2.GetOutput()]

triFilt = [vtk.vtkPolyData(), vtk.vtkPolyData()]

# Converts the polydatas in Triangles and check Normals are ok
for ind in range(2):
	
        polyCopy = vtk.vtkPolyData()
	polyCopy.ShallowCopy(poly[ind])

	trif = vtk.vtkTriangleFilter()
	trif.SetInput(polyCopy)
	trif.PassVertsOff()
	trif.PassLinesOff()
	trif.Update()

	normalf = vtk.vtkPolyDataNormals()
	normalf.SetInput(trif.GetOutput())
	normalf.SetFeatureAngle(60.0)
	normalf.ComputePointNormalsOn()
	normalf.ComputeCellNormalsOn()
	normalf.SplittingOff()
	normalf.ConsistencyOff()
	
         # Had to use this in order for the data to be correct. Doc says:
NOTE: This assumes a completely closed surface (i.e. no boundary edges) and
no non-manifold edges. If these constraints do not hold, all bets are off.
	normalf.AutoOrientNormalsOn() 

	normalf.Update()

	triFilt[ind].ShallowCopy(normalf.GetOutput())

# Design Boolean operation
boolFilter = vtk.vtkBooleanOperationPolyDataFilter()
boolFilter.SetOperation(Operation) #default value is 1: Intersection
boolFilter.SetInput(0,triFilt[0]);
boolFilter.SetInput(1,triFilt[1]);
boolFilter.Update()

# Result
InterPoly = boolFilter.GetOutput()

Using this three times (one for each boolean operation type) resulted in the
attached picture (Grey, the two meshes; Red, Union result : Green,
Intersection result ; Blue, Difference result ). The two meshes do not
touch, but still there is a PolyData generated by the Intersection
operation, and I cannot understand why.
<http://vtk.1045678.n5.nabble.com/file/n5725561/Real_test.png> 



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