Hi Avila, usually OBJ files contain polygon mesh data where objects are made up of a bunch of little flat facets.

MoI is not designed to work with that kind of faceted data, MoI is set up to work with CAD surfaces and solids.

So usually it is not very feasible to import OBJ data into MoI, you would want to use a polygon mesh editing program to work with polygon mesh data, not MoI.

If your OBJ file is structured to have Sub-D smoothing applied to it then that is an exception and you can bring in a Sub-D polygon control cage using MoI's built in subd converter which can be found in the UI on the SubD tab on the side pane under SubD > Create > "From file".

It is also possible to convert a non-sub-d OBJ file into wireframe lines which can then be opened with MoI. There is a converter available for that on the wiki page here:
https://moi3d.com/wiki/Resources#Obj23dmWireframe_converter

- Michael