Conversion from IPT to 3DS is not supported yet :(

An IPT file extension is used for Autodesk Inventor objects.

Autodesk Inventor is a CAD application that engineers and product designers use to construct prototypes of mechanical products. These prototypes, referred to as assemblies, consist of several individual parts joined together. Each Inventor part is saved in an IPT file.

Inventor users can import IPT parts from outside the program or create their IPT parts using the Inventor's part design tools. Typically, users begin by creating a 2D drawing of a part before transforming that drawing into a 3D model. Thus, an IPT file may contain either a 2D or 3D object. Files in IPT format can be opened using Autodesk Inventor 2017, Autodesk Inventor View 2017, Autodesk Fusion 360, and SpaceClaim Engineer.

3DS is one of the file formats used by the Autodesk 3D modeling, animation and rendering software. It once was native for the old Autodesk 3D Studio DOS and eventually has grown to become a de facto industry standard for transferring models between 3D programs, or for storing models for 3D resource catalogs.

3DS is aimed at providing an import/export format, retaining only essential geometry, texture and lighting data.