I create a vtkpolydata and a vtkImagedata ,add a vtkActor and vtkVolume to the same render,the vtkpolydata is a closed surface, and intersect with the volume .
when I set the vtkActor opacity to 1,
it looks all right,but when i set the opacity to 0.5,
it looks strange , like the volume covers the suface , I don’t know what caused this problem,
Can you give me some advice? thanks