Filament spool for short sections

I created this spool to hold short sections (e.g. ~10m) of filament that I have purchased but came without a spool. The outer diameter is large so that it will not require coiling the filament tightly to place it on the spool. The spool is unscrewable so that you can add and remove the filament without re-winding it.

I've released this as GNU GPL as it includes the threads.scad library. It's not clear to me if I can apply the GPL to just the scad files and CC-BY-SA to the stl files, which is