[vtkusers] how can i get vtkPolyData from a VRML file?

[陈皓]

i am a new user of VTK 
the question is ,i wana get vtkPolyData from a VRML file
now, i know i can use vtkVRMLImporter to read a vrml file and render it ,but if i don't want to render it and i need only the vtkPolyData , how can i do ?

thanks!