vtkPolyDataConnectivityFilter提取模型的连通分区和遍历访问连通分量

实现遍历访问模型中所有连通分区。

运行结果

方法介绍

重点是多次使用vtkPolyDataConnectivityFilter。先第一次使用vtkPolyDataConnectivityFilter提取所有连通分区出来，再在for循环使用vtkPolyDataConnectivityFilter提取指定的分区。

源代码

完整代码可以直接编译运行

//找出连通分区数量并遍历连通分区
#include <iostream>
#include <vtkNew.h>
#include <vtkSphereSource.h>
#include <vtkCleanPolyData.h>
#include <vtkAppendPolyData.h>
#include <vtkPolyDataConnectivityFilter.h>
using namespace std;

int main()
{
    
    
	//创建三个位置不同的球体
	vtkNew<vtkSphereSource> sphere1;
	sphere1->SetCenter(0, 0, 10);
	sphere1->SetRadius(2);

	vtkNew<vtkSphereSource> sphere2;
	sphere2->SetCenter(0, 10, 0);
	sphere2->SetRadius(2);

	vtkNew<vtkSphereSource> sphere3;
	sphere3->SetCenter(10, 0, 0);
	sphere3->SetRadius(2);
	//将三个球体合并为一个vtkPolyData数据
	//这一个vtkPolyData数据里就有三个球体，即三个连通分量
	vtkNew<vtkAppendPolyData> append;
	append->AddInputConnection(sphere1->GetOutputPort());
	append->AddInputConnection(sphere2->GetOutputPort());
	append->AddInputConnection(sphere3->GetOutputPort());
	//提取所有连通分量，获取连通分量数目
	vtkNew<vtkPolyDataConnectivityFilter> connectivity;
	connectivity->SetInputConnection(append->GetOutputPort());
	connectivity->SetExtractionModeToAllRegions();
	connectivity->Update();
	int num = connectivity->GetNumberOfExtractedRegions();
	cout << "连通分区的总顶点数量: " << connectivity->GetOutput()->GetNumberOfPoints() << endl;
	//遍历所有连通分区并访问数据
	for (int i = 0; i < num; i++)
	{
    
    
		//提取指定区域
		vtkNew<vtkPolyDataConnectivityFilter> region;
		region->SetInputConnection(connectivity->GetOutputPort());
		region->SetExtractionModeToSpecifiedRegions();
		region->AddSpecifiedRegion(i);
		//需要清除孤立点
		vtkNew<vtkCleanPolyData> clean;
		clean->SetInputConnection(region->GetOutputPort());
		clean->Update();
		cout << i + 1 << "分区的顶点数量: " << clean->GetOutput()->GetNumberOfPoints() << endl;
	}
	return 0;
}