How to convert IGS
to Rhino?

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.

Rhinoceros (typically abbreviated Rhino, or Rhino3D) is a commercial 3D computer graphics and computer-aided design (CAD) application software. Rhinoceros geometry is based on the NURBS mathematical model, which focuses on producing mathematically precise representation of curves and freeform surfaces in computer graphics (as opposed to polygon mesh-based applications).

Rhinoceros is used in processes of computer-aided design (CAD), computer-aided manufacturing (CAM), rapid prototyping, 3D printing and reverse engineering in industries including architecture, industrial design (e.g. automotive design, watercraft design), product design (e.g. jewelry design) as well as for multimedia and graphic design.

The Rhinoceros file format (.3DM) is useful for the exchange of NURBS geometry. The Rhino developers started the openNURBS Initiative to provide computer graphics software developers the tools to accurately transfer 3-D geometry between applications. An open-source toolkit, openNURBS includes the 3DM file format specification, documentation, C++ source code libraries and .NET 2.0 assemblies to read and write the file format, on supported platforms (Windows, Windows x64, Mac, and Linux).