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

Powermill is a 3D Computer-aided manufacturing app developed by Autodesk Inc. It runs on Microsoft Windows and is used in many different engineering industries to determine optimal toolpaths to reduce time and manufacturing costs.

Powermill rapidly creates toolpaths on large, complex parts, works with surfaces, solids and STL meshes. It uses efficient roughing strategies and can create gouge and collision free toolpaths, which can be edited and optimized. The software obtains comprehensive range of finishing toolpaths, user-defined macros and templates for automated CAM, extensive library of tool types for use with 3- and 5-axis milling, and specialist tools for demanding industries and applications.

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.