Convert off to 3ds

Download and install the latest version of Filestar.
Right click on one or more Off file(s) on your desktop and select Convert with Filestar.
Type convert to 3ds in the search box.
Press Convert.

What is the difference between .off and .3ds?

Name: Object File Format; 3D Studio Max
Extension: .off; .3ds
Category: 3D; 3D
Developer: Microsoft; Autodesk
Description: It is an a file that stores 2D and 3D objects with the description of composing polygons of a geometric object.; 3DS is one of the file formats used by the Autodesk 3ds Max 3D modeling, animation and rendering software.
MIME Type: application/x-object; application/x-3ds
Sample: sample.3ds
Wikipedia: .off on Wikipedia; .3ds on Wikipedia