"in the Openscad script you can set a flag that will simply rotate upside-down the whole swiss cheese inside the gnomon, and build a ‘Southern-hemisphere’ version of the gnomon. This way, the ‘roo can simply use this Southern-hemisphere sundial exactly the same way a cow or a penguin would use their Northern-hermisphere version the sundial, with just one difference: the ‘roo will have to point the tip of his sundial toward the South Pole." 
But penguins live in the southern hemisphere. Conspiracy?! Maybe!
It must be a Galapagos penguin: https://en.wikipedia.org/wiki/Galapagos_penguin
> Angela Brett 1 month ago
> +Tainer Waynes Maybe he confused the English word penguin with the French word pingouin, which means auk (a bird similar to a penguin which lives in the Northern Hemisphere.) The French word for penguin is actually manchot. :)
Par abus de langage, le pingouin est souvent confondu avec les manchots, des oiseaux de la famille des sphéniscidés qui vivent dans l’hémisphère sud et ne volent pas. La principale raison de cette confusion est la ressemblance avec la plus grande des deux espèces de pingouin, le grand pingouin.
Une autre source d’erreur est la parenté étymologique entre le mot français pingouin et celui désignant les manchots dans les principales langues européennes comme pinguïn en néerlandais, pingüino en espagnol, Pinguin en allemand, pinguino en italien, penguin en anglais, пингвин (pingvin) en russe, ou encore pinguim en portugais.
Dans de nombreuses langues, deux termes différents sont utilisés pour désigner les deux espèces de pingouin, ce terme n’a donc pas de traduction exacte. En anglais, le terme Great Auk désigne le grand Pingouin, auk étant un terme générique désignant le plus souvent l’ensemble des alcidés. Le petit Pingouin est quant à lui appelé razorbill. En catalan ou en italien, respectivement les termes de gavot et alca sont en revanche utilisés comme en français pour désigner les deux espèces.
And they made a short video on the same: https://www.youtube.com/watch?v=M09oIwSQ6q4
October 29, 2015 at 10:21 am
Penguins at the North Pole??
October 29, 2015 at 10:56 am
If you were a penguin on a touristic trip, where would
you go for the Xmas holidays ?
(or use the southern hemisphere sundial stick and point it south. this just swaps what end the base is on.)
Also, I encourage everyone to donate to the guy, which you can do here: http://www.mojoptix.com/donations-page/
What he is doing is just so wonderful and inspiring in so many ways, and to top it all off, he's doing it without muddling up his content with ads and other gimmicks. Please repay him for what he is so selflessly giving out for free and without strings attached. (He is sharing all files, all 3d designs etc... of such complicated things, a lot of people don't do that, so this guy is just super brilliant). I don't make a lot of money but I'll be giving him $50. I hope you can give even more. :)
This one is interesting...uses a mask of slits http://www.fransmaes.nl/genk/welcome-e.htm (iframes, ugh...click #8 in the left sidebar)
Edit: Another cool implementation http://www.voshart.com/SUN-CUBE-prototype
They are sold at http://www.digitalsundial.com/
I've never used any 3D designing program other than SketchUp.
* If you're a programmer, the learning curve of OpenSCAD is almost non-existent. Assuming you're familiar with 3D modelling concepts, it should take an hour or two to go through and play with the entire feature set of OpenSCAD  (which I did).
* It's simple and the defaults are sensible.
* Your model is basically a line based source file which can be put under git and improved through pull requests, etc.
* Your model is easily made parametric. Last model I made was a tripod mount where I could simply change the angle of the legs or wall thickness and everything would adopt.
* OpenSCAD can be used as an 2D vector modeler as well. For me, it's replaced Inkscape 90% of the time.
There are however things that are not as easily doable with OpenSCAD. One feature lacking is constraint solver so you have to do some back of the napkin trig for such things. I've also found it non-trivial to simply "chamfer" an edge, like I could in FreeCAD.
The prog is fast, fully portable (as in "can run from usb drive") and tiny (~2MB iirc). Also has a wealth of export options including g-code for cnc, though prolly pretty rudimentary for 2d routing.
There is a good active fork of Solvespace on Github 
The first may have been just my wimpy computer but as I approached what I wanted the whole process got slower and slower. Some of that could be combatted by adding tunable resolution parameters to keep the number of polygons down. It should be pointed out that OpenSCAD doesn't really do curves. Everything is polygons which at least in the roughing you design out phase are rather visible.
The second issue I ran into is that some of the way things are done makes it harder to work than you would like. Complex data structures aren't really a thing. If I remember rightly there are arrays but nothing more complex. You can't iterate over the points in a shape. There doesn't appear to be a way to extract dimension data from a shape. CSG is nice but sometimes you want more.
These may not have been that much of an issue if I were doing something different. Trying to wrap a 3D model around another non-uniformly curved 3D model just isn't really what the tool was designed for. And to be fair, I couldn't get AutoDesk's free tools to do what I wanted either. That is probably due partially to a lack of experience in the area and probably pushing the tools to do things they just didn't have in mind.
Examples of when you'd use OpenSCAD:
* Computational art (e.g. convert a photo into some 3D model, print a sound wave, etc.)
* Gears, sprockets, etc.
* Fasteners (nuts, bolts, screws, etc.)
Examples of things you would be insane to use OpenSCAD for, and should definitely use something like SolidWorks:
* Cordless drill
* CNC machine
* Well pretty much everything except the stuff I listed above
For many purposes, such as the author sharing his designs with random viewers, that makes it a non-starter.
It does have significant drawbacks... but if you're just getting into CNC stuff, it has fairly decent CAM functionality in built, making it a reasonable intro thing. :)
I really enjoy cubify design which is a cheap alternative to solidworks. I have designed a ton of stuff with it.
They both have their virtues. I use both for designing my 3d models depending on what I need. I think being experienced in both will make you better on each piece of software.
Also apparently a 'digital' sundial was patented at one point - https://en.wikipedia.org/wiki/Digital_sundial
http://www.hineslab.com/digital-sundial/ - The notebook drawings are cool
A fractal is "any of various extremely irregular curves or shapes for which any suitably chosen part is similar in shape to a given larger or smaller part when magnified or reduced to the same size".
A hologram is "a three-dimensional image reproduced from a pattern of interference produced by a split coherent beam of radiation".
The 3rd dimensional component of the hologram is modulated by the position of the sun instead of the observer.
Truthfully, the problem they have is that it's still cheaper, easier, and more accurate to do this with a subtractive CNC machine.
Plus you aren't material limited.
You are right that in practice, you would likely want a 4th axis rather than messing around, but a 4 axis setup is just not a big deal (the 4th axis on my woodworking CNC cost < 4k)
I am wondering how much extra time it will take for 3D printing as we add support for 10 minute time interval, 1 minute interval and then seconds (extra set of digits HH:MM:SS).
Also will it be practically possible to have second-level granularity?
If that can work, I guess both the design (I can't see how to design one object that shows a number for say 5 seconds; now fit thousands in a single object) and the engineering challenge would be quite a bit higher (at submicrometer scales), and that the resulting contrast of the display would be a lot lower.
If you imagine a really long tube, any light entering at an angle will eventually hit the side, and if the sides do not reflect any light, nothing will come through the tube.
I don't want to bother doing the math to figure out how big the diameter of the sundial would have to be to have sub-minute accuracy, but I think it is very possible.
Though the intensity would fade as the sun moves, so maybe you could potentially have some sort of intensity filter?
That might not count as a sundial, though.
As ever someone had already had the same idea written the code to produce the OpenSCAD files for different wordings and put it on Github:
This is very cool, I'm going to have to play with OpenSCAD.
But that's just a gut feeling.
Accuracy helps a lot when using understanding of some things' existence to find another thing and its attributes (incomplete understatement). Proof making and checking helps a lot for someone to stay true to their beliefs and maintain a consistently accurate path.