CATIA CAD software supports IGES format (.igs, .iges) just fine and can process the data for making new parts (.catpart). If you do not have access to CATIA, then you have to use some kind of other CAD program with CATIA's file type support, or some dedicated CAD / 3D model conversion solution.
Open IGES file Open CATPART fileA CAD converter with huge format support
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