Summary

This is a paper thin 21 centimeter ruler. It's best to print with 2 filaments for contrast. This way you can see the tick marks and numbers clearly. I recommend the best resolution detail setting. If you only have 1 extruder then pause the print after the z-axis (.5mm) is completed. So when (.55mm) begins printing, change the filament to the 2nd color and continue printing.

There are a lot of rulers posted. However this one takes up the least amount of filament. I usually print some of these up for people who have broken items they want replicated in Tinkercad, so they can provide the measurements. This is an ideal design if you have a classroom of students and need to provide a handful (cheap solution).

PLA
Ultra Detail --> .05mm
No Infill
No support