Is there a way that Fabman can measure filament used per 3D printed project?
We would like our makers to have a monthly allowance of filament that they can use, after which they must provide their own filament or wait until the next month to 3D print next projects.
What measurement of filament do you have in mind?
As far as I know, not directly, but I know that Happylab is using plugin in Octorpint and we, here in FabLab Brno, are using custom FW for Prusa printers (MK2.5S, MK3S, Mini is in development) where we added RFID reader and cusrtom PCB which act like bridge and we are saving amount of filament which was used in session metadata. You can find some more info here and if you are iinterested in this integration, you can write me. 
I wrote a script that imports material consumption for Ultimaker and BCN printers.