Hi Robert, for .obj files there is an option in the UI for disabling writing material assignments, under Options > Import/Export > "Obj options" > "Write material assignments".

You can also disable writing UV coordinates for .obj files by a setting in moi.ini - go to Options > General > "Edit .ini file" button and inside moi.ini find [OBJ Export] WriteTextureCoordinates=y and change it to =n like this:

[OBJ Export]
<...>
WriteTextureCoordinates=n

There is also a similar moi.ini setting for disabling UV coordinates to LWO format:

[LWO]
<...>
WriteTextureCoordinates=n


There is not currently a way to disable writing material/surface assignments to LWO files but I will see about adding that in.

- Michael