I thought the OP was talking about their dog getting into an indoors litter box. It’s not for the dog to play in, it’s to keep them out. (In case you’re joking, let me be the first to say whoooosh to myself lol)
For cat poop, we got one of these dog playpen enclosures: Amazon Basics - Octagonal Foldable Metal Exercise Pet Play Pen for Dogs, Fence Pen, Single Door, Small, 60 x 60 x 30 Inches, Black a.co/d/6Nz4VuU
It is set so that the cats can get through a gap easily, but Henry can’t get his head through without causing a huge racket.
I’m not very knowledgeable about 3D printing. Are you saying that the model isn’t a sphere that is then interpreted by a printer to fit its filament size? I guess I assumed models were vectored like SVG image file?