Box clip with vtkTableBasedClipDataSet

I’m trying to clip an unstructuredgrid using vtkTableBasedClipDataSet. I use the unstructuredgrid as the input of vtkTableBasedClipDataSet and vtkbox as the clip function.

The result doesn’t look like it’s interpolated, the algorithm just determine the position of the points and remove those cells whose points are outside the box. But when use the plane as clip function, it works.

Is it reasonable?Or some settings need to be specific.

I just started learning VTK, please forgive me.