December 2018 update:
1/ Fillet added to remove sharp bottom edge
2/ Travel mini-soap dispenser settings added (works really handy, actually)
3/ freecad-file: measurement bug fixes.
Rechargable silicagel is very useful for keeping the filament dry. This silicagel-container was designed for fitting inside the filament spool, to keep the filament dry whilst stored in a bag (eg, many filaments comes in a zip-lock bag). Its height can be adjusted to convenient length for most filament rolls (60-90mm) as the lid and base has overlapping sides. It is easy to open, and not the least it is simple to load/unlad it without spilling silicagel all around. Air openings are both at the base and on top of the lid as these surfaces are the free surfaces within the spool. However, I use these containers for every occasion where silicagel is used to keep items dry (eg, hard disk storage).
prusa, filamentum PLA
copper, blue, red, black, silver
I once printed the container using a 0.6mm nozzle, noting that in order for the parts to fit well together, I needed to increase the diameter of the lid (which I did in the slicer settings) by 1%.
Printing time 3h 17min
About the freecad source file
The item was constructed using freecad (my first "real" construction ever in freecad). I use the "freecad-daily" updates (which I strongly recommend for any freecad user). I have not tried using the construction with the freecad stable release.
If you prefer to edit the design, in the freecad-document you can change the major parameters (eg diameter, height) easily by adjusting parameters in column B in the spreadsheet included in the document. Please note, the grid was constructed using solids with boolean operations so if you would like to change that part, it might be a good idea to reconstruct it using the "part design" workbench which would improve the design.
Please note, if you buy rechargable silicagel, as to my knowledge blue-coloured silicagel might be unhealthy so better stick to the orange colour.