vtkImageData m_img数据变化后，如何让三维图像重新生成，
m_cast = vtkSmartPointer<vtkImageCast>::New();
m_cast->SetInput(m_img);
m_ComositeFun =vtkSmartPointer<vtkVolumeRayCastCompositeFunction>::New();
m_volumeProperty =vtkSmartPointer<vtkVolumeProperty>::New();
m_compositeOpacity = vtkSmartPointer<vtkPiecewiseFunction>::New();
m_color = vtkSmartPointer<vtkColorTransferFunction>::New();
m_renWin = vtkSmartPointer<vtkRenderWindow>::New();

m_img->Modified();
m_renWin ->Render();

2L正解
data变换后，好多时候需要把内存中的数据强制刷新下