VTK-vtkMassProperties

前言：本博文主要记录vtk中用于计算体积和表面积的接口vtkMassProperties，分享该接口使用时的注意事项，使用方法以及算法实现原理，希望能给各位小伙伴带来一点帮助！

目录

vtkMassProperties

描述：

注意事项

使用方法

实现原理

VTK参考样例

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vtkMassProperties

描述：

估算三角形网格的体积、面积和形状索引。算法基于离散形式的散度定理实现，一般假设输入的模型为闭合曲面。

*形状索引，还不太理解。

注意事项

1. 输入数据为闭合曲面，若为非闭合，体积计算出错。

2. 输入数据为三角面片，即数据不能存在Strips和Polys的形式。建议采用vtkTriangleFilter对数据进行三角划分。

3. 若输入数据定义了多个封闭对象，请考虑使用vtkMultiObjectMassProperties接口进行计算；也可以考虑采用vtkPolyDataConnectivityFilter提取连接区域后，采用vtkMassProperties对每个连接区域进行计算。

使用方法

    vtkMassProperties* massProperties = vtkMassProperties::New();
    if (pd->GetNumberOfPolys() > 0 || pd->GetNumberOfStrips() > 0)
    {
        vtkTriangleFilter* triFilter = vtkTriangleFilter::New();
        triFilter->SetInputData(pd);
        triFilter->Update();

        massProperties->SetInputData(triFilter->GetOutput());
        massProperties->Update();

        triFilter->Delete();
        triFilter = nullptr;
    }
    else
    {
        massProperties->SetInputData(pd);
        massProperties->Update();
    }

实现原理

待添加。

VTK参考样例

#include <vtkSmartPointer.h>
#include <vtkMassProperties.h>
#include <vtkTriangleFilter.h>
#include <vtkFillHolesFilter.h>
#include <vtkPolyDataNormals.h>

#include <vtkBYUReader.h>
#include <vtkOBJReader.h>
#include <vtkPLYReader.h>
#include <vtkPolyDataReader.h>
#include <vtkSTLReader.h>
#include <vtkXMLPolyDataReader.h>
#include <vtkSphereSource.h>
#include <vtksys/SystemTools.hxx>

namespace
{
vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName);
}

int main (int argc, char *argv[])
{
  vtkSmartPointer<vtkPolyData> polyData = ReadPolyData(argc > 1 ? argv[1] : "");;


  vtkSmartPointer<vtkFillHolesFilter> fillHolesFilter =
    vtkSmartPointer<vtkFillHolesFilter>::New();
  fillHolesFilter->SetInputData(polyData);
  fillHolesFilter->SetHoleSize(1000.0);

  vtkSmartPointer<vtkTriangleFilter> triangleFilter =
    vtkSmartPointer<vtkTriangleFilter>::New();
  triangleFilter->SetInputConnection(fillHolesFilter->GetOutputPort());

  // Make the triangle windong order consistent
  vtkSmartPointer<vtkPolyDataNormals> normals =
    vtkSmartPointer<vtkPolyDataNormals>::New();
  normals->SetInputConnection(triangleFilter->GetOutputPort());
  normals->ConsistencyOn();
  normals->SplittingOff();

  vtkSmartPointer<vtkMassProperties> massProperties =
    vtkSmartPointer<vtkMassProperties>::New();
  massProperties->SetInputConnection(normals->GetOutputPort());
  massProperties->Update();
  std::cout << "Volume: " << massProperties->GetVolume() << std::endl
            << "    VolumeX: " << massProperties->GetVolumeX() << std::endl
            << "    VolumeY: " << massProperties->GetVolumeY() << std::endl
            << "    VolumeZ: " << massProperties->GetVolumeZ() << std::endl
            << "Area:   " << massProperties->GetSurfaceArea() << std::endl
            << "    MinCellArea: " << massProperties->GetMinCellArea() << std::endl
            << "    MinCellArea: " << massProperties->GetMaxCellArea() << std::endl
            << "NormalizedShapeIndex: " << massProperties->GetNormalizedShapeIndex() << std::endl;

  return EXIT_SUCCESS;
}

namespace
{
vtkSmartPointer<vtkPolyData> ReadPolyData(const char *fileName)
{
  vtkSmartPointer<vtkPolyData> polyData;
  std::string extension = vtksys::SystemTools::GetFilenameExtension(std::string(fileName));
  if (extension == ".ply")
  {
    vtkSmartPointer<vtkPLYReader> reader =
      vtkSmartPointer<vtkPLYReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".vtp")
  {
    vtkSmartPointer<vtkXMLPolyDataReader> reader =
      vtkSmartPointer<vtkXMLPolyDataReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".obj")
  {
    vtkSmartPointer<vtkOBJReader> reader =
      vtkSmartPointer<vtkOBJReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".stl")
  {
    vtkSmartPointer<vtkSTLReader> reader =
      vtkSmartPointer<vtkSTLReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".vtk")
  {
    vtkSmartPointer<vtkPolyDataReader> reader =
      vtkSmartPointer<vtkPolyDataReader>::New();
    reader->SetFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else if (extension == ".g")
  {
    vtkSmartPointer<vtkBYUReader> reader =
      vtkSmartPointer<vtkBYUReader>::New();
    reader->SetGeometryFileName (fileName);
    reader->Update();
    polyData = reader->GetOutput();
  }
  else
  {
    vtkSmartPointer<vtkSphereSource> source =
      vtkSmartPointer<vtkSphereSource>::New();
    source->SetPhiResolution(51);
    source->SetThetaResolution(51);
    source->Update();
    polyData = source->GetOutput();
  }
  return polyData;
}
}