My name is Duncan, I'm a dev on the Medium team. I know some people have been asking for an import guide, so I wrote up some short guidelines. This guide is targeted specifically to Reference Meshes, though there's certainly some overlap with stamps. There isn't all that much to it, but with textured meshes coming online it seemed like as good a time as any. If there's anything you'd like more detail on, let me know and I can update it.