Hi Nick, you can set up different materials in MoI by assigning objects to different styles. Then when you export to .obj or .lwo formats the style assignments in MoI will become material assignments and the styles list will become a materials list. Then you should be able to edit the materials.

For Octane it would probably be best to export using .obj format and use the setting for "Create: Quads & Triangles" in the meshing options dialog box that will be shown during the mesh export.

- Michael