Happy to report that the opacity channel maps load on first use of an imported .obj. Went back to an old TG2 project and reloaded the house with no glass and just the glass separated out first after deleting the original so it was a first load in TG3.4 and you can see from the yellow-orange light coming out the opacity maps worked and the glass is nicely reflecting where appropriate. I'm uploading the image to Image sharing as there seems to be no way from here. Default Street...... will be in the title.