Although it is not available on the public online generator Boxes.py supports generating formats like DXF directly using the pstoedit utility. Unfortunately this broke recently due to ghostscript dropping the -dDELAYBIND parameter in 9.22.

Luckily ghostscript upstream decided to add it back in 9.23. So if you run into trouble consider updating or downgrading your ghostscript installation. 

Pstoedit also indicated that the next version may work without -dDELAYBIND. So as soon as 3.71 comes out the issue may be off the table for ever.

Fedora Bug report