First modest success It's hard to describe how filthy and disgusting a ventilation hatch in the bathroom was. I thought I could easily replace it with a newer one, but it turned out that the modern standard-size hatch doesn't fit the older frame. After wasting hours trying to figure out how to fit the hatch into the frame, I decided to just 3D print my own design. As my 3D printer can't handle larger prints, I had to split the design into several parts, and then glue them together. Not the most elegant solution, but it will do for now.