3D Sundial Inventor Julien Coyne
 

French inventor and maker of things Julien Coyne of Mojoptix has created an intriguing digital sundial gnomon that can be 3D printed.  His software design (dated 13 October 2015) uses the 3D open software OpenSCAD described as "The Programmers Solid 3D Computer Aided Design Modeller".[http://www.openscad.org/about.html].

In a Mojoptix video [http://www.mojoptix.com/fr/2015/10/12/ep-001-cadran-solaire-numerique] (available in both French and English) the inventor describes how the digital gnomon shows digital time by making virtual "light tunnels" that burrow through a half-cylinder 3D software object.  He accurately describes how a sundial works good (except of course for placing a penguin at the north pole) and how the "tiny tunnels" generate "a complicated Swiss Cheese" of holes and grooves that result in a gnomon that casts sunlight in a dotted pattern of numbers that change promptly every 20 minutes running from 10am (10:00) to 4pm (16:00). 

The sundial is adjustable for any latitude and rotates slightly to accommodate daylight savings time, site longitude, or the date's equation of time (though no markings are made so making these angles are guesswork). His free, open software script allows 3D printing for either the Northern or Southern hemisphere. 

For those who do not have a 3D printer, he makes the digital dial available from his on-line store for $54 USD plus shipping.  Even with a fast 3D printer, the dial takes about 35 hours of printer time.  This digital gnomon is a wonderful addition to both the world of dialing and 3D printing.  The only down-side is that the dotted numerals have light  tunnels placed too close together, resulting in an entrance angle of only +/- 15 deg.  Since the sun annually moves +/- 23.5 deg in declination, this digital gnomon sadly won't work when the sun heads toward the summer solstice from about 1 May to 10 Aug and likewise blanks out in the winter from about 5 Nov to 5 Feb.