Complicated Calculated Solution To 3D-Printed Puzzle

3D printers have made a lot of things possible that were either extremely difficult or downright impossible with traditional tooling. Certain shapes lend themselves to 3D printing, and materials and tooling costs are also generally greatly reduced as well. One thing that may not be touched on as often, though, is their ability to rapidly prototype solutions to complex mathematical problems, in this case taking the form of a 3D printed maze, known as a dodecahedral holonomy maze, with an interesting solution.

The puzzle presents itself as a sphere composed of various inlaid hexagons which form a track for the puzzle piece, or “rook”. The tracks create the maze for the rook to travel, as some paths are blocked when the rook is oriented in certain ways. To solve the puzzle, the player must rotate the rook by moving it around the hexagons in such a way that its path isn’t physically blocked by any of the pegs in order to successfully reach the exit. This might seem like a fun toy to have on its surface, but the impressive thing about this is that the solutions are designed to reduce the likelihood of solving the puzzle with any “brute force” methods while at the same time having more than one path that will reach the exit as well as several bottlenecks that the puzzle solver must traverse as well.

There are actually many possible puzzles that can be produced in this size and shape, and all have predetermined solutions with cleverly chosen paths. This might seem like a lot but when you realize that the entire build from concept to 3D modeling to implementation was done by [Henry Segerman] and a group of other mathematicians at Oklahoma State University it starts to become more clear how the puzzle was so well-designed. In fact, we’ve featured some of his other mathematically-modeled builds in the past as well.

Thanks to [Inne] for the tip!

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CadQuery Comes Of Age

Now, we know what some of you are going to say — “Oh man, not another programmatic CAD tool, what’s wrong with OpenSCAD?” — and you may be right, but maybe hold on a bit and take a look at this one, because we think that it’s now pretty awesome! OpenSCAD is great, we use it all the time round these parts, but it is a bit, you know, weird in places. Then along comes CadQuery, and blows it out of the water ease-of-use and functionality wise. Now, we’ve seen a few mentions of CadQuery over the years, and finally it’s become a full-blown toolset in its own right, complete with a graphical frontend/editor, CQ-editor. No odd dependencies on FreeCAD to be seen! That said, installing FreeCAD is not a bad thing either.

The goal is to have the CadQuery script that produces this object be as close as possible to the English phrase a human would use.

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Art of 3D printer in the middle of printing a Hackaday Jolly Wrencher logo

What To Expect From 3D Scanning, And How To Work With It

3D scanning and 3D printing may sound like a natural match for one another, but they don’t always play together as easily and nicely as one would hope. I’ll explain what one can expect by highlighting three use cases the average hacker encounters, and how well they do (or don’t) work. With this, you’ll have a better idea of how 3D scanning can meet your part design and 3D printing needs.

How Well Some Things (Don’t) Work

Most 3D printing enthusiasts sooner or later become interested in whether 3D scanning can make their lives and projects easier. Here are a three different intersections of 3D scanning, 3D printing, and CAD along with a few words on how well each can be expected to work.

Goal Examples and Details Does it work?
Use scans to make copies of an object.
  • 3D scan something, then 3D print copies.
  • Objects might be functional things like fixtures or appliance parts, or artistic objects like sculptures.
Mostly yes, but depends on the object
Make a CAD model from a source object.
  • The goal is a 1:1 model, for part engineering purposes.
  • Use 3D scanning instead of creating the object in CAD.
Not Really
Digitize inconvenient or troublesome shapes.
  • Obtain an accurate model of complex shapes that can’t easily be measured or modeled any other way.
  • Examples: dashboards, sculptures, large objects, objects that are attached to something else or can’t be easily moved, body parts like heads or faces, and objects with many curves.
  • Useful to make sure a 3D printed object will fit into or on something else.
  • Creating a CAD model of a part for engineering purposes is not the goal.
Yes, but it depends

In all of these cases, one wants a 3D model of an object, and that’s exactly what 3D scanning creates, so what’s the problem? The problem is that not all 3D models are alike and useful for the same things.

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FreeCAD Vs SolveSpace

When you are ready to design real things, you’ll find simple CAD programs can be pretty limiting. Serious modern designs tend to use parametric modeling where you don’t necessarily set dimensions and positions of everything but instead constrain the design by describing the relationship between different elements. For example, you can create a vertical line and constrain other lines to be parallel, perpendicular, or form a given angle with that line. There are many tools that can do that, including FreeCAD and SolveSpace, two programs that [Joko Engineeringhelp] uses to create a complex compressor blade and it really shows the differences and similarities between the two tools.

You probably don’t need this particular design, but watching over someone’s shoulder while they do a complex design can be very valuable. Being able to see the differences between the two tools might convince you to learn one or the other or maybe even switch.

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A Word Clock You Don’t Have To Actually Build To Enjoy

The great thing about word clocks is that while they all follow the same principle of spelling out the time for you, they come in so many shapes, sizes, and other variations, you have plenty of options to build one yourself. No matter if your craft of choice involves woodworking, laser cutting, PCB design, or nothing physical at all. For [Yasa], it was learning 3D modeling combined with a little trip down memory lane that led him to create a fully functional word clock as a rendered animation in Blender.

Inspired by the picture of a commercially available word clock, [Yasa] remembered the fun he had back in 2012 when he made a Turkish version for the Pebble watch, and decided to recreate that picture in Blender. But simply copying an image is of course a bit boring, so he turned it into an actual, functioning clock by essentially emulating a matrix of individually addressable LEDs using a custom texture he maps the current time to it. And since the original image had the clock positioned by a window, he figured he should have the sun move along with the time as well, to give it an even more realistic feel.

Of course, having the sun situation in real-time all year round would be a bit difficult to render, so [Yasa] choose to base the scene on the sun during spring equinox in his hometown Stockholm instead. You can see the actual clock showing your local time (or whichever time / time zone you set your device to) on his website, and his write-up is definitely a fun read you should check out if you’re interested in all the details or 3D modeling in general — or just to have a look at a time lapse of the clock itself. As he states, the general concept could be also used to model other word clocks, so who knows, maybe we will see this acrylic version or a PCB version of it in the future.

3DBuzz Closes With A Final Gift

If you wanted to learn about creating modern computer games, 3DBuzz had some of the best tutorials around. In fact, some of the tutorials about C#, C++, Android, and math would be useful for anyone, while the ones about game art and modeling in Maya are probably mostly for game developers. While these were once available only by subscription, the company — now defunct — has left them available for download via this BitTorrent file.

We don’t know enough about things like Blender and Maya to evaluate the material, but it is well regarded and the ones we do know something about seem very high quality. There are, for example, many videos about C++ and C# that are very professional and cover quite a few topics.

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Vintage Print Processor Fixed With 3D Printing

If you don’t know what a print processor is, don’t feel bad. There’s precious few people out there still running home darkrooms, and the equipment used for DIY film development is about as niche as it gets today. For those looking to put together their own darkroom in 2019, buying second hand hardware and figuring out how to fix it on your own is the name of the game, as [Austin Robert Hermann] found out when he recently purchased a Durst Printo Print Processor on eBay.

The auction said the hardware was in working order, but despite the fact that nobody would ever lie on the Internet, it ended up being in quite poor condition. Many of the gears in the machine were broken, and some were simply missing. The company no longer supports these 1990’s era machines, and the replacement parts available online were predictably expensive. [Austin] determined his best course of action was to try his hand at modeling the necessary gears and having them 3D printed; two things he had no previous experience with.

Luckily for [Austin], many of the gears in the Printo appeared to be identical. That meant he had several intact examples to base his 3D models on, and with some educated guesses, was able to determine what the missing gears would have looked like. Coming from an animation background, he ended up using Cinema 4D to model his replacement parts; which certainly wouldn’t have been our first choice, but there’s something to be said for using what you’re comfortable with. Software selection not withstanding, he was able to produce some valid STLs which he had printed locally in PLA using an online service.

Interestingly, this is a story we’ve seen play out several times already. Gears break and wear down, and for vintage hardware, that can be a serious problem. But if you’ve got a couple intact gears to go by, producing replacements even on an entry level desktop 3D printer is now a viable option to keep these classic machines running.