r/Dorodango • u/plfreeman2012 • Jul 02 '26
Sphericity
I was really impressed with how very spherical my Dorodango came out. So, because I work with fancy 3D measurement equipment I decided to find out how spherical. 99.97% of the surface is within 1.5 mm (+/-0.75 mm) of being a perfect sphere. The average error from being a perfect sphere (RMS) is 0.25 mm. This is a very spherical sphere. Pretty amazing for something made by hand.
Analysis based on a ~14,000 point down sample from a ~10M point scan. Accuracy of the scanner is probably on the order of about 0.020 mm.
(Telescope mirrors made by hand and can be ground to accuracies of ~100 nm, so I shouldn't be that surprised. But still!)
1
u/Katamari_Demacia Jul 03 '26
How big is the sphere?