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.

blocks

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.

cut

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.

zheng

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.

cheeks

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.

fluted

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

half

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

nail

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

bondo

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.

mace

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.

beans

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.

Curiasser and curiasser

Faire Play backer rewards are all I’m thinking about these days. The Athena Makeover Kits are done and should be winging their way towards my midrange backers shortly, and now I’m printing a suit of field plate armor for one of my top backers. My printer is working on a lovely pair of sabatons in the background as I type this.

Nothing’s ever completely straightforward at this level of 3D printing, and of course now I’ve got a strange little gremlin that didn’t surface the last time I printed a cuirass: I’m getting a small line up the side of the print where my printer’s print head stops, lifts, and begins a new layer. Take a look at the cuirass on the left.

cuirass lines

I’m doing my best to make this suit as nice as possible and I’m aesthetically offended by artifacts of the printing process like this one.

What’s wrong here? The geometry hasn’t changed since the first print, the filament’s exactly the same, and as far as I know I’m using the same slicing algorithm. I have replaced a worn-out print nozzle, but I can’t imagine that’d be the source of the issue. I’ve changed every setting I can think of and I’m still getting this weird little printing track.

Truth be told, it’s a fairly minor aesthetic problem in the grand scheme of things and now that I look at the original armor I do see some traces of this artifact there, too.

Even if it can’t be completely eliminated, it can at least be put on the back side where it’s less visible. The best way to do this is to just rotate the model 180° around the Z axis before printing. Easy peasy: take a gander at the cuirass on the right.

1946_pr

Ars Longa, Vita Brevis

My maternal grandfather was a painter. Not by trade but by passion; by day he designed lingerie patterns in The City and by night he retreated to his Bronx basement to exorcise his demons with oils and canvas. Or so my narrative of his life goes, cobbled together from snippets told by his wife and children.

Grandpa Joe died of cancer when I was six, so I never had the opportunity to know him well. My strongest memories of him are of the kind man who walked us to the corner candy store on every visit, and of the dried soil in the flowerpot next to his sickbed, dappled with orange seeds.

The smell of cigar smoke still conjures hazy, pleasant images of his presence.

To this day you can’t attend a family gathering without seeing one of Grandpa Joe’s paintings. Every uncle and aunt had (and still has) at least one of his pieces, every one a silent witness to history, now thoroughly infused with lasagna fumes and family drama. Some have even filtered down to grown grandchildren; we have one proudly displayed in an honored spot in my house.

One of his grandest works hung in our home throughout my upbringing. It’s a huge painting by a six-year-old’s standards, and still looms larger in my mind than it actually is. He painted this in 1946, in a world still reeling from war.

1946

There are two distinct sides in this conflict; left and right are rendered differently in style and tone. Panicked innocents flee from the blast of a fantastic sunset in the center. Michelangelo’s God touches no Adam here and instead judges from the middle of the battle.

Staring down from the family room wall, this painting spoke to me like Sauron’s Eye to Frodo.

“I see you,” it rasped.

I’ve felt this painting’s pull all my life. If computers hadn’t caught on in the 80′s I’d have eventually made a living airbrushing heavy metal scenes on vans. But despite years of 10 PRINT "HELLO", the notion that I could be an artist myself had already been planted in my head by Grandpa Joe’s work.

Grandpa excelled at painting details. Look at the capitals of the columns on either side of the painting and you’ll see delicate details and almost-arabesques. These are exactly the kind of decorative motifs I’d like to include in the Faire Play parade armor. Another painting has an appropriate flourish I’d like to include as an homage to my precursor, so I’ll burgle from this:

1967

My guess is that this is a depiction of the Virgin Mary appearing to my uncle and mother as children. I don’t think this is a rendering of an actual event, because you can bet your britches if Mom had witnessed a Marian apparition we’d have heard about it every Thanksgiving for the last 40 years.

Here’s the detail that I’d like to use as a recurring motif, from the lower left of the painting.

flourish sample

My old workflow for this involved tracing the flourish in Illustrator, importing the EPS, creating a planar trim and then tessellating to produce a polygon model. That’s the quick and easy path, but ultimately that journey is beset by N-gons and nonmanifold geometry, difficult to seamlessly join to an existing model.

Instead I’ll bring the image into Maya and trace the outline with the combination of Create Polygon tools, edge extrusion, and vertex pulling. This helps me to keep a model that’s built exclusively out of quads; it’s much less likely to cause me problems later on when I boolean the many flourishes into the base cuirass mesh.

flourish grow

This is going to be a slow, but easy, process, so I sip my coffee, put in the earbuds and some Quirks and Quarks podcasts, and achieve Csíkszentmihályi’s flow as I work. Twenty minutes later I have this.

finished flourish

The translated flourish doesn’t fit the space in the armor exactly, so it needs a little lattice work to deform it to the space above the bird’s wing.

flourish molded

And finally some extrusion and mirroring and it’s ready to become part of the parade armor.

extruded and mirrored

I’ll be appropriating details from both of these paintings over the next few weeks while I decorate the Faire Play parade armor.

A note to my future grandchildren, yet unconceived, osmosing this post with retinal HUDs on the shores of Central Park: do not judge my low-resolution geometry too harshly, and please pilfer your ancestors’ work to better your own.

Also, thanks to Dad for photographing the paintings and sending them my way.