There are no restrictions for using this Qt code in any project.
To make changes to this code requires a commercial license of Qt
to keep it free for everyone.  Using a free version of Qt causes
this Qt code to become GPL'd.  We don't want that.  If you want to
make changes with a free version of Qt, you can copy it and 
make your own changes for yourself.

Changes to the following files are restricted, but not limited to 
any new ones added after this writing:
  QVTKWidget.h QVTKWidget.cxx QVTKWidgetPlugin.cxx QVTKWidget.xpm