Hello! What does the maxscript actually? You can turn the textures visibility on in the viewport with the max menu but it doesn't interfere with the export does it? In any case you need to convert the vray/corona/mr/revit materials to standard before exporting to obj/fbx within 3dsmax. With 3dsmax 2017-2018 you have a scene converter inside max, which is useful to convert any material to standard. BUT as usual sometimes you need to switch to manual pilot as lots of things like fallof, blend, color correction, 2-sided, mix and other things aren't easily translatable to standard shader. I use fbx to export to SU (and import with Fluid Importer Pro) but obj works nice too.

@Alan-Fraser Thanks Alan this was a great link to Youtube tutorial + really helped me increase the materials. . I did not know that you could do this . I'd tried many years ago with bmp + JPG

I use Adobe Bridge at the moment. It works fine too.