Maybe you must first use the free Instant Mesh for transform your OBJ in "Quads" then use SUBd
(or of course Blender)

https://github.com/wjakob/instant-meshes

You have also Import OBJ by Max Smirnov
http://moi3d.com/forum/get_attachment.php?webtag=MOI&hash=196c71c0e707b0c68f267a376fa30df3&filename=ImportObj.v.1.5.2015.09.10.zip

and / Or OBJ to 3md by Michael Gibson http://moi3d.com/download/Obj23dmWireframe.zip