Newest Way To Fail

Wow. Totally didn’t see this one coming.

So I’ve been furiously prototyping models for Kickstarter #2. The keystone model for this next project is what we in the business call a giant-ass bucket of geometry. The gCode works out to something like 90MB (!) of data.

Models like this take forever to print, so rather than try to maintain a USB connection between the computer and the printer it’s generally best to print stuff like this from an SD card. A little interruption like a monitor going to sleep can kill the USB if one isn’t careful, and then you’ve got yourself a half-finished print.

The model started printing at 9AM yesterday after some very careful calibration and painters’ tape finessing, and everything was going great until about 2:30AM today, when I came downstairs to find this:


Mother pus bucket.

I’ve never seen this before, so to teh Googles we go. Turns out, at least in the opinion of some electrical engineers, the Replicator1’s Mightyboard generates a lot of electrical interference can cause the bot to fail over long prints.

Live and learn, back to the drawing board, and a host of other try-try-again platitudes must suffice to get me through the day.

Appleton Maker Fest

Appleton, Wisconsin is the nicest little city you’ve never heard of. Along with low crime rates and a thriving local music scene, it’s home to Lawrence University, a Harry Houdini museum with an interactive straightjacket exhibit, and the first Edison hydroelectric plant in the United States. Last weekend the Appleton Maker Space hosted their first Maker Fest.


The Appleton Maker Space is tucked back in a mostly-underutilized commercial space off the west end of Appleton’s main drag, just the kind of location where you’d expect a hackerspace to be gestating.

Bonus: AMS is right across the street from some of the finest deep-dish pizza in town.*

Pizza wasn’t needed this day because, being that this is Wisconsin, the Appleton Maker Space provided a bratwurst concession for peckish attendees.

Our coastal and international readers should be aware that no event in Wisconsin can be held without at least thirty pounds of bratwurst in attendance. Pretty sure it’s in the state constitution.

The space was packed with dedicated Makers– I’ll leave it to their website to point out all the cool hardware they’ve got over there. Here’s one corner of the event, complete with the obligatory LAN party of kids playing Minecraft.


Amid the chaos one usually associates with a makerspace’s being open to the chaos, someone was personalizing a banana for a younger attendee by etching her name into the skin. Of all the projects I’ve ever envisoned for a laser cutter, this’d be about the last one I’d ever come up with. Fantastic idea. I’d totally personalize all my bananas if we had a laser cutter at Zheng Labs.


Show and tell time arrived and the assembled crowd asked for an “ominous puffy doll” to be modeled and printed on one of the RepRaps. I already had the laptop out so I fired up Maya and made this little guy. Concept to execution in ten minutes.

first pass

Later on I buffed out some of the stray vertices and cut a hole in the back so that Ominous Puffy can stick to your fridge with the addition of a neodymium magnet.

ominous puffy

You can download Ominous Puffy from his page in The Forge.

Heads up, badgers. I’ll be blogging, tweeting, and instagramming the ever-living snot out of Maker Faire Milwaukee in a couple of weeks, so if you’d like to meet up IRL and geek out over filament diameters drop me a line.

* deep dish isn’t pizza. New York style is pizza. Bring it, haters.

B-(A+C): Booleans and We The Builders

3D printing luminary Todd Blatt is of late heading up his second bit of crowdsourced Americana with his We The Builders project, Ben Franklinstein.

I missed out on the first pass at this with George Crowdsourcington, and since Todd overtipped our server for his share of Korean Barbecue the last time we met IRL, jumping in to help out with Ben Franklinstein seemed like The Right Thing To Do.

Here’s how this works. Everyone who wants to be involved downloads a piece of a scanned Ben Franklin bust. We print it, scrawl the piece’s coordinates on an inward-facing side, and ship it to Todd and others who assemble all the pieces somewhere in Baltimore.

The result’s a nifty pastiche of plastics in the form of a Founder. A quilt of quadrilaterals, if you will. Here’s what George Crowdsourcington looks like, all assembled.

I’ve printed two blocks for the latest project. My gold block is plain Jane, but I decided to do a little shenmeshenme on the blue one.


The first order of business was carving out a hollow inside the block. One’s first thought is to make a perfectly cubical void, but that’ll cause the roof to sag when printed on an FDM printer. So a peaked void it is, tapering to a single vertex at the top.


Maya models surfaces, not solids, so subtracting the void (A) from the main geometry (B) isn’t a valid operation; B minus A equals B in this case. Printing B will get you a solid block, which is not what We The Builders want in this case.

The solution is to model a thin snorkel (C) connecting the void to the outside. This snorkel is mathematically legit, but too small for the printer’s resolution. The end result will be a printable void with no visible snorkel. We’re doing B-(A+C) here. Woo! Booleans.

You can grab the model here if you’d like to inspect this snorkel for your own mean self.

Midway through the print we do the old pause-the-print-and-drop-an-object-in-the-void trick, in this case a golden zheng. You can’t see the zheng from the outside of the printed model, but it does rattle a bit.


And then it’s a simple matter of finishing the print, boxing it up, and shipping it off to Todd and company.

The crowdsourcing phase of We the Builders is scheduled to wrap up in mid-September, and they’ve still got a few blocks to go. It’s free and a lot of fun, so go ahead and add your 3D printed stamp to this creative endeavor.

Faire Play Recurve Bow Now on Shapeways!

Here it is, folks! I’ve redesigned the Faire Play recurve bow so that people without access to 3D printers can get one on Shapeways.

Just click here and Shapeways will happily print you a bow and quiver on one of their industrial-sized dream-making machines.

shapeways bow

shapeways quiver

In her youth, Barbara Millicent Roberts (“Barbie” to the world at large) passed through a phase where she adorned her handwritten i’s with a little heart instead of a dot. By the time she completed astronaut training she had outgrown such frippery, and besides it caused too much consternation among the top brass and crew-cut stiffs at Mission Control.

She retained a secret, unprofessional fondness for the motif, and every now and then, when she wasn’t vaccinating pets, transplanting hearts, or busting perps in back alleys, she’d sketch a heart or two on a cocktail napkin and wonder how her life would have been different if she’d remained a hearter of i’s.

just bow and quiver

Zheng’s Garden Guardian

zhengs garden guardian

downloadNecessity! Mother of invention and all that. One could, I suppose, just jam a wooden stake into the ground to prevent a garden hose from raking over one’s flowerbeds, but that would lack panache and, worse, deprive one of an opportunity to use a 3D printer and Bondo on the same project.

The first step in this design is grabbing a horse head off Thingiverse and modify it to suit my purposes. The original is almost exactly what I need, and with just a couple of tweaks I can have it atop my new garden guardian.

knight original

First, that mane! This chess piece was designed as part of an OpenGL chess application, and is by necessity low-polygon. Selecting just the mane and deleting the faces is pretty easy, and then it’s just a matter of closing up the holes.

remove mane

I’ll add a lattice to re-pose the horse so he’s got a more regal bearing: less Mr. Ed and more Seabiscuit. Normally the overhang under the chin would be a huge printing problem, but I’ll be splitting this model in half down the middle before printing. The only overhang I’ll need to be concerned with is the ears.

knight lattice

And it probably makes sense to smooth the model a bit at this point. Sometimes a one-size-fits-all smoothing algorithm can obscure important details, but I need some extra vertices so I can bump out the cheeks and nostrils.

knight smoothed

I’ve always been partial to the stylized manes on Tang Dynasty horse sculptures, so butch mohawk of awesome it is for this piece. Now he looks like Kallark the Gladiator as I start to sculpt his cheeks with Maya’s sculpt geometry tool.


Scratch that, I think he’s starting to resemble Benedict Cumberbatch. Must be the flared nostrils.

cumberbatch 1

The mane is looking a little blah and not very Tang dynasty, so I add some detail and some stylized bristle.

fancy mane

It’s easy to whip up a fluted cylinder for the base, and I rob a few bits from my Curtain Rod Bracket, +1 for the coiled rings at the top and bottom of the cylinder. They’ll help to catch a garden hose and keep it on the guardian.


Then I’ll split the model down the middle and carve out a nail-shaped recess before printing.


You can get one of these spikes at pretty much any hardware store.


Once the halves have been glued together, all one needs is a little Bondo to fill the seam before painting.


And then of course there’s sanding and buffing, and undercoating and overcoating and a second coat of paint and all the stuff one needs to do to make this look less like plastic. The rest of the post-production process is well-documented on my Instagram, including but not limited to the old straighten-out-the-PLA-by-putting-the-model-on-a-warm-skillet trick.

Baby’s First Mace

I’ve been waiting for an excuse to print Dutchmogul’s most excellent Baby’s First Mace, easily in the top five of Designs I Wish I’d Thought of First. Some friends recently obliged by welcoming a baby into this world.


Dutchmogul designed the mace with a pommel, handle, and head to make multicolored printing easy. I stopped the head print halfway through to drop a few black beans inside. Now they’re stuck in there for the lifetime of the biodegradable PLA and make for a lovely rattle.


We packed up the mace with some fresh onesies (note: autocorrect changes onesies to onuses, which is quite telling) and some fine coffee for the benefit of the newly sleepless mom and dad, and sent the package off to darkest Michigan in order to begin the child’s medievalist indoctrination posthaste.

Pro tip: when purchasing new baby clothes as a gift, be an outlier– everyone else will be buying fancy 0-3 month dinosaur outfits, but the haggard parents will very much appreciate your gift of plain white 4-6 month onesies down the road when baby starts pooping for real.