Conversion from mathcad to CATPart is not supported yet :(

Mathcad is computer software primarily intended for the verification, validation, documentation and re-use of engineering calculations. It is used by engineers and scientists in various disciplines – most often those of mechanical, chemical, electrical, and civil engineering.

Mathcad is part of a broader product development system developed by PTC, and often utilized for the many analytical touch points within the systems engineering processes. It integrates with PTC’s other solutions that aid product development, including Creo Elements/Pro, Windchill, and Creo Elements/View. Its live feature-level integration with Creo Elements/Pro enables Mathcad analytical models to be directly used in driving CAD geometry.

CATPart is a native format developed by Dassault Systems for storing parts of the assemblies created in CATIA V5 software suite, which is extensively used in mechanical engineering including aerospace, automotive, shipbuilding and other domains.

CATPart stores geometry, structure and metadata of 3D models dedicated to single parts. Multiple CATPART files can be combined into a CATProduct assembly file.

Among CAD applications that support CATPart extension are Autodesk Inventor, Fusion 360, and 3ds Max.