Hi tomot - this won't work in general because MoI is designed to work with NURBS geometry (curved objects), not polygon mesh geometry.

Your OBJ or LWO file is storing a polygon mesh type of object, that isn't the type of object that MoI works on. 3DM files can contain both NURBS and polygons, and in this case your conversion ends up creating a 3DM file that only has polygons in it.

It is possible for MoI to create a polygon mesh object from a smooth NURBS surface by dicing it into little bits, but it is not easy to go in the other direction. Sort of like how you can mash up apples to make applesauce, but it is not easy to start with applesauce and go back to apples again.

But I do want to add an option in a while to make it possible to at least read a mesh object in as a wireframe of lines so you could use it as a reference in constructing a new version of it or something.

- Michael