[vtkusers] help:a problem with vtksweptsurface !(patented library)

[susan]

hello all,
    I am doing a project to create swept surface and volume with C++.I find that VTK has corresponding algorithm and classes,such as vtkimplicitmodeller and vtkSweptsurface .but as I know that those classes and functions are parts of patented library.I can find all other libraries except the patented library,that is to say ,I can not use corresponding classes and functions.I wondered how I could do with creating swept surface ? 
   Thanks for helping me.