[vtkusers] Wrong volume calculation (vtkMassProperties)

[AlexeyM]

Hello,
I want to compute volume of arbitary polyhedron. I made test code, where
polyhedron is created, converted to PolyData, triangulated and, finally,
volume is computed. So, the volume of created polyhedron should be equal to
1.5, but vtkMassProperties output 0.4375. Points are entered right and
Paraview visualise figure right. Please, help me to understand what's wrong
with code? Thanks.

#include <iostream>
#include <ostream>

#include <vtkSmartPointer.h>
#include <vtkCylinderSource.h>
#include <vtkTransform.h>
#include <vtkTransformPolyDataFilter.h>
#include <vtkCubeSource.h>
#include <vtkTriangleFilter.h>
#include <vtkIntersectionPolyDataFilter.h>
#include <vtkPolygon.h>
#include <vtkCellArray.h>
#include "vtkDataArray.h"
#include <vtkMassProperties.h>
#include "vtkUnstructuredGrid.h"
#include "vtkVersion.h"
#include "vtkIdList.h"
#include "vtkPoints.h"
#include "vtkPolyhedron.h"
#include "vtkPolyData.h"
#include "vtkCellArray.h"
#include "vtkPointData.h"
#include "vtkXMLUnstructuredGridWriter.h"

using namespace std;

int main()
{
	vtkSmartPointer<vtkPolyhedron> aDodecahedron =
vtkSmartPointer<vtkPolyhedron>::New();

	for (int i = 0; i < 10; ++i)
	{
		aDodecahedron->GetPointIds()->InsertNextId(i);
	}
	vtkIdType dodechedronPointsIds[10] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9};

	aDodecahedron->GetPoints()->InsertNextPoint(0, 0, 0);
	aDodecahedron->GetPoints()->InsertNextPoint(1, 0, 0);
	aDodecahedron->GetPoints()->InsertNextPoint(0, 1, 0);
	aDodecahedron->GetPoints()->InsertNextPoint(1, 1, 0);
	aDodecahedron->GetPoints()->InsertNextPoint(0, 0, 1); //4
	aDodecahedron->GetPoints()->InsertNextPoint(1, 0, 1); //5
	aDodecahedron->GetPoints()->InsertNextPoint(0, 1, 1); //6
	aDodecahedron->GetPoints()->InsertNextPoint(1, 1, 1); //7
	aDodecahedron->GetPoints()->InsertNextPoint(2, 0.5, 1); //8
	aDodecahedron->GetPoints()->InsertNextPoint(2, 0.5, 0); //9

	vtkIdType face[7][5] = { { 0, 1, 9, 3, 2 },
	{ 4, 5, 8, 7, 6 },
	{ 0, 1, 5, 4 },
	{ 3, 9, 8, 7 },
	{ 2, 3, 7, 6 },
	{ 0, 2, 6, 4 },
	{ 1, 9, 8, 5 } };

	vtkSmartPointer<vtkCellArray> dodechedronFaces =
vtkSmartPointer<vtkCellArray>::New();

	dodechedronFaces->InsertNextCell(5, face[0]);
	dodechedronFaces->InsertNextCell(5, face[1]);
	dodechedronFaces->InsertNextCell(4, face[2]);
	dodechedronFaces->InsertNextCell(4, face[3]);
	dodechedronFaces->InsertNextCell(4, face[4]);
	dodechedronFaces->InsertNextCell(4, face[5]);
	dodechedronFaces->InsertNextCell(4, face[6]);

	
	vtkSmartPointer<vtkUnstructuredGrid> ugrid1 =
vtkSmartPointer<vtkUnstructuredGrid>::New();
	ugrid1->SetPoints(aDodecahedron->GetPoints());
	ugrid1->InsertNextCell(VTK_POLYHEDRON, 10, dodechedronPointsIds, 7,
dodechedronFaces->GetPointer());

	vtkSmartPointer<vtkXMLUnstructuredGridWriter> writer =
vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();

	writer->SetInputData(ugrid1);

	writer->SetFileName("polyhedron1.vtu");
	writer->SetDataModeToBinary();
	writer->Update();

	aDodecahedron->SetFaces(ugrid1->GetCell(0)->GetFaces());
	aDodecahedron->Initialize();

	//vtkSmartPointer<vtkPolyData> polyData = aDodecahedron->GetPolyData();
	
	vtkSmartPointer<vtkPolyData> polyData =
vtkSmartPointer<vtkPolyData>::New();
	vtkSmartPointer<vtkPoints> points = vtkSmartPointer<vtkPoints>::New();
	vtkSmartPointer<vtkCellArray> cellArray =
vtkSmartPointer<vtkCellArray>::New();
	vtkSmartPointer<vtkPolygon> polygon = vtkSmartPointer<vtkPolygon>::New();


polygon->GetPointIds()->SetNumberOfIds(ugrid1->GetCell(0)->GetNumberOfPoints());

	points = ugrid1->GetCell(0)->GetPoints();

	for (int i = 0; i < ugrid1->GetCell(0)->GetNumberOfFaces(); i++)
	cellArray->InsertNextCell(ugrid1->GetCell(0)->GetFace(i));

	polyData->SetPoints(points);
	polyData->SetPolys(cellArray);


	vtkSmartPointer<vtkTriangleFilter> triangles =
vtkSmartPointer<vtkTriangleFilter>::New();
	triangles->SetInputData(polyData);
	//triangles->SetInputConnection(polyData->GetOutput());
	triangles->Update();




		std::ostream& os = std::cout;
		triangles->Print(os);

	vtkSmartPointer<vtkMassProperties> mass =
vtkSmartPointer<vtkMassProperties>::New();
	//mass->SetInputConnection(triangles->GetOutputPort());
	mass->SetInputData(triangles->GetOutput());
	mass->Update();

	mass->Print(os);

		return 1;
	}




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