[vtkusers] How can I save vtkOBJReader output?

[akbarjan bayiz]

Hello, all!
I am using the vtkOBJReader to read and render an .obj file, which works well. But, I also want to save its output, I mean those polydata generated by vtkOBJReader, into another single file. How can I do this? I want to save all the data in the right form, so that I can reach and render them later. I need an C++ example.
By the way, I tried the "GetOutput" command, but it didn't work properly. I am new to VTK, and I really need an explicit, full example. 
Thank you very much in advance. 

Best regards, 
Abayiz