I think it's automated. The printer prints one layer then moves to a specified spot and let's a camera take a picture. This would keep cycling until the print is complete. I don't know what he uses to do that though.
Good video :) could you give me the link for the filament guide shown at about 0:41? I'm using OSB as well for my enclosure and could find only filaments guide fitting for the Ikea tables :D
Thanks! I made it for 8mm OSB. I haven't upload it anywhere and I don't know if I have the files anymore. So I need to search it. What is your OSB thickness? If I have time I can make new one.