用到的類為vtkPolyDataToImageStencil 

效果：

#include <vtkVersion.h>
#include <vtkSmartPointer.h>
#include <vtkPolyData.h>
#include <vtkImageData.h>
#include <vtkSphereSource.h>
#include <vtkMetaImageWriter.h>
#include <vtkPolyDataToImageStencil.h>
#include <vtkImageStencil.h>
#include <vtkPointData.h>
#include <vtkCutter.h>
#include <vtkPlane.h>
#include <vtkStripper.h>
#include <vtkLinearExtrusionFilter.h>
#include <vtkXMLPolyDataWriter.h>
#include <vtkImageData.h>
#include <vtkMetaImageReader.h>
#include <vtkSmartPointer.h>
#include <vtkInteractorStyleImage.h>
#include <vtkRenderer.h>
#include <vtkImageActor.h>
#include <vtkImageMapper3D.h>
#include <vtkRenderWindow.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkTesting.h>

void convertData2()
{  
	vtkSmartPointer<vtkSphereSource> sphereSource = 
		vtkSmartPointer<vtkSphereSource>::New();  
	sphereSource->SetRadius(20);
	sphereSource->SetPhiResolution(30);
	sphereSource->SetThetaResolution(30);
	vtkSmartPointer<vtkPolyData> pd = sphereSource->GetOutput();
	sphereSource->Update();

	vtkSmartPointer<vtkImageData> whiteImage = 
		vtkSmartPointer<vtkImageData>::New();    
	double bounds[6];
	pd->GetBounds(bounds);
	double spacing[3]; // desired volume spacing
	spacing[0] = 0.5;
	spacing[1] = 0.5;
	spacing[2] = 0.5;
	whiteImage->SetSpacing(spacing);

	// compute dimensions
	int dim[3];
	for (int i = 0; i < 3; i++)
	{
		dim[i] = static_cast<int>(ceil((bounds[i * 2 + 1] - bounds[i * 2]) / spacing[i]));
	}
	whiteImage->SetDimensions(dim);
	whiteImage->SetExtent(0, dim[0] - 1, 0, dim[1] - 1, 0, dim[2] - 1);

	double origin[3];
	origin[0] = bounds[0] + spacing[0] / 2;
	origin[1] = bounds[2] + spacing[1] / 2;
	origin[2] = bounds[4] + spacing[2] / 2;
	whiteImage->SetOrigin(origin);

#if VTK_MAJOR_VERSION <= 5
	whiteImage->SetScalarTypeToUnsignedChar();
	whiteImage->AllocateScalars();
#else
	whiteImage->AllocateScalars(VTK_UNSIGNED_CHAR,1);
#endif
	// fill the image with foreground voxels:
	unsigned char inval = 255;
	unsigned char outval = 0;
	vtkIdType count = whiteImage->GetNumberOfPoints();
	for (vtkIdType i = 0; i < count; ++i)
	{
		whiteImage->GetPointData()->GetScalars()->SetTuple1(i, inval);
	}

	// polygonal data --> image stencil:
	vtkSmartPointer<vtkPolyDataToImageStencil> pol2stenc = 
		vtkSmartPointer<vtkPolyDataToImageStencil>::New();
#if VTK_MAJOR_VERSION <= 5
	pol2stenc->SetInput(pd);
#else
	pol2stenc->SetInputData(pd);
#endif
	pol2stenc->SetOutputOrigin(origin);
	pol2stenc->SetOutputSpacing(spacing);
	pol2stenc->SetOutputWholeExtent(whiteImage->GetExtent());
	pol2stenc->Update();

	// cut the corresponding white image and set the background:
	vtkSmartPointer<vtkImageStencil> imgstenc = 
		vtkSmartPointer<vtkImageStencil>::New();
#if VTK_MAJOR_VERSION <= 5
	imgstenc->SetInput(whiteImage);
	imgstenc->SetStencil(pol2stenc->GetOutput());
#else
	imgstenc->SetInputData(whiteImage);
	imgstenc->SetStencilConnection(pol2stenc->GetOutputPort());
#endif
	imgstenc->ReverseStencilOff();
	imgstenc->SetBackgroundValue(outval);
	imgstenc->Update();

	// 	vtkSmartPointer<vtkMetaImageWriter> writer = 
	// 		vtkSmartPointer<vtkMetaImageWriter>::New();
	// 	writer->SetFileName("SphereVolume.mhd");
	// #if VTK_MAJOR_VERSION <= 5
	// 	writer->SetInput(imgstenc->GetOutput());
	// #else
	// 	writer->SetInputData(imgstenc->GetOutput());
	// #endif
	// 	writer->Write();  





	//////////////////////////////////////////////////////////////////////////
	//流水線
	vtkImageGaussianSmooth *gaosi=vtkImageGaussianSmooth::New();

	//高斯平滑處理
	gaosi->SetInputData(imgstenc->GetOutput());
	gaosi->SetDimensionality(3);
	gaosi->SetRadiusFactors(2,2,1); 
	gaosi->Update();

	vtkImageCast *cast=vtkImageCast::New();

	//轉換成vtk資料格式
	cast->SetInputConnection(gaosi->GetOutputPort());
	cast->SetOutputScalarTypeToUnsignedChar();;
	cast->ClampOverflowOn();
	cast->Update();

	vtkOpenGLVolumeTextureMapper3D *glmapper=vtkOpenGLVolumeTextureMapper3D::New();

	//3D紋理對映法
	glmapper->SetInputConnection(cast->GetOutputPort());

	vtkPiecewiseFunction * psfunction=vtkPiecewiseFunction::New();



	//透明度傳遞函式
	psfunction->AddPoint(  0.0 , 0.0);
	psfunction->AddPoint(  40.0 , 0.0);
	psfunction->AddPoint(  50.0 , 0.3);
	psfunction->AddPoint(  110.0, 0.4);
	psfunction->AddPoint(  120, 0.5);
	psfunction->AddPoint(  130, 0.6);
	psfunction->AddPoint(  190, 0.8);
	psfunction->AddPoint(  255,  1.0);

	vtkColorTransferFunction * colfunction=vtkColorTransferFunction::New();

	//顏色傳遞函式
	colfunction->AddRGBPoint(0.0,0.5,  0.3,  0.2);
	colfunction->AddRGBPoint(50.0, 0.8,  0.5,  0.5);
	colfunction->AddRGBPoint(110.0, 0.6,  0.2, 0.3);
	colfunction->AddRGBPoint(190.0, 0.81, 0.27, 0.1);
	colfunction->AddRGBPoint(255.0, 0.5,  0.9,  0.9);

	vtkVolumeProperty * volpro=vtkVolumeProperty::New();

	//體資料屬性
	volpro->SetColor(colfunction);
	volpro->SetScalarOpacity(psfunction);
	volpro->ShadeOn();
	volpro->SetInterpolationTypeToLinear();
	volpro->SetAmbient(0.2);
	volpro->SetDiffuse(0.9);
	volpro->SetSpecular(0.2);
	volpro->SetSpecularPower(10);

	vtkVolume * data=vtkVolume::New();

	//體資料對映器和屬性
	data->SetMapper(glmapper);
	data->SetProperty(volpro);

	vtkRenderer *render=vtkRenderer::New();
	vtkRenderWindow *renwin=vtkRenderWindow::New();
	vtkRenderWindowInteractor *iren=vtkRenderWindowInteractor::New();

	renwin->AddRenderer(render);
	renwin->SetInteractor(iren);

	//繪製器
	render->AddVolume(data);
	render->SetBackground(0,0,0);
	render->ResetCameraClippingRange();

	//繪製視窗
	renwin->AddRenderer(render);

	renwin->Render();




	// 	 	vtkMetaImageWriter* writer = vtkMetaImageWriter::New();
	// 	writer->SetInputData(resultImage);
	//writer->SetFileName("E:\\PolyDataToImageStencil\\bin2\\Debug\\polyDataToImage_liver.mha");
	// 	 	writer->SetFileName("D:\\liver.mha");
	// 	 	writer->Write();

}