Every time I make a new object (cloned from the 12th century vase) it is invisible in the catalog (that is, it is in the catalog with a star, but no thumbnail) and invisible when I place it in game. It never happened before, although I haven't made an object for a while. I followed an old YT tutorial by Rebecah.
Can someone tell me what I am doing wrong? I have attached an example file.

Try changing "default" to "sculpturechinavase_design" in the GMDC and see if that helps. If it does, it'll also fix the texture since it wasn't linked due to that.

It worked! Thank you so much!
I don't remember ever having to change that line before - have I missed something? It's not in Rebecah's tutorial or JWoods one here.

You can name the mesh groups anything you want - but then you have to make sure that doesn't break anything. I usually see "default" when doing conversions and I just make sure to change the name to match what I cloned before exporting from Milkshape.

(BTW, thank you! <3)