Conversion from IGS to CATIA V6 (3D XML) is not supported yet :(

An IGS extension (Initial Graphics Exchange) is a 2D or 3D CAD vector file that can store wireframes, surfaces, solids, etc. IGS is mainly used for exchanging CAD drawings based on the Initial IGES (Graphics Exchange Specification) format.

The IGS file structure is based on the ASCII text-based format, which is used in numerous CAD software applications for delivering high-end graphics.

Among CAD applications that support IGS extension are Autodesk 3ds Max, Autodesk Fusion 360, Dassault Systemes CATIA, and Autodesk Inventor.

3DXML is an open-standard proprietary 3D file format developed and supported by Dassault Systemes. 3DXML files are typically created as exports from Dassault Systemes' 3DEXPERIENCE application. The 3DXML file is a zip archive file consisting of a BOM file and one or more 3D representations stored in either XML or binary format. Compact file size allows users to transfer 3D XML quickly and embed it into websites, emails, and various MS Office documents. Therefore, the format is commonly used to integrate 3D data into technical documentation.