Tag Archives: maker faire

Hacking Barbie

I’m tickled, TICKLED! I tell you, to see that an autographed Seej tournament bloxen has made it into the background of 3DKitBash‘s latest Quin Kickstarter video. It’s at 1:35 or so, but stick around for the entire experience, it’s worth the watch.

I met Quincy Robinson at Maker Faire NYC a month or two ago. Neat guy, brimming with creativity. Quin’s an interesting Kickstarter: a fully-3d printed fashion doll. Barbie for maker kids.

I foresee a burgeoning cult following among adult maker dollbros too. I’m already sketching out 3d printed accessories on napkins, and I’ve mostly outgrown playing with dolls.

I’m interested to see how this project develops. Best of luck to Quincy, Quin, and the rest of the crew at 3DKitBash.

Anatomy of A Remix

remix

download

One of the highlights from World Maker Faire 2013 in NYC was meeting Thingiverse All-Star cerebus333. He’s friendly, engaging, and incredibly prolific; I can’t recall a week’s recent passing where he hasn’t posted at least one new model to his collection.

I was honored to take home an autographed Rock Frog from Cerebus’ collection, and I promised him that I’d take a shot at remixing his work when I got back home. Here’s the original model, standing about 7 inches tall.

original

Cerebus has designed the Rock Frog to print reliably on an FDM printer, and print reliably it does: the mesh is manifold and it’s physically quite stable on the build platform. My plan is to re-pose the original and turn it into something usable as an RPG elemental or golem miniature, and that’s going to require some geometry edits.

Step 1

Cerebus designed the Rock Frog’s knuckles to lay flat on the printing bed. If they’re going to potentially be raised up in the air they’ll need to look more like fingers. I’ll delete the old flat surface and replace it with some vaguely-knucklelike ridges. A little sculpting here and there and we’ve got something that looks good enough for now– my experience with 3D printing tells me that much more detail here isn’t going to print at this scale so there’s not much point in overworking the model.

Note the strange triangulation in the sole of the foot, because I’ll fix that in step 2.

I’ve split him in half down the YZ axis so I only have to fix one hand before mirroring and rejoining the model.

edited fist

Step 2

The foot geometry is fine for printing, but not so good for deformations. This should be a straightforward fix, and afterwards Rock Frog will be able to put some weight on the ball of his foot.

fixed feet

Step 3

Rock Frog’s mouth is closed in the original. I’ll find the inside crease of his mouth, split the geometry, and then open up his mouth. A note for folks not used to working with character models; it’s generally easiest to work on one half of a model and then mirror it, which is why the original Rock Frog has been split down the middle here.

mouth

Step 4

Bipedal 3d characters are usually modeled in T-Pose, with arms outstretched. This pose helps when assigning weights to vertices, step one in rigging a character. I’m not going to invest a lot of time in a full animation rig here, just enough to intuitively bend Rock Frog at his joints.

Rock Frog’s legs are already in a good position for vertex assignment, so no adjustments need be done there. Once I’ve got him in T-pose I’ll inspect the mesh one more time to make sure the mesh is closed and manifold.

back

If you’d like to pose Rock Frog on your own, go ahead and download the t-posed model.

Step 5

I reach way back into the mists of time for inspiration, back to a time when Xiao Zheng was a fifth grader surreptitiously poring over the 1st Edition AD&D monster Manual under the covers. I move some joints around here and there until Rock Frog more or less resembles David C. Sutherland III’s classic drawing of an earth elemental, with allowances made for the gravity-plagued medium of supportless FDM printing.

The posing created some self-intersecting geometry where I didn’t bother to weight the vertices properly. Bad mojo. I can easily fix this by painting the vertices with a smoothing algorithm, but doing so while the model’s rigged to joints can be slow and produce unpredicatble results.

At this point it makes sense for me to detach the geometry from its joints, freezing Rock Frog in this position. I’ll save a version of the rigged model in case I want to re-pose him later.

back

And now a test print. Almost everything prints OK, but the heel of his right fist hangs out in space just a bit too much. Frankly I should have seen this coming. Part of the problem is that I’m printing at a .3mm layer height for the test, but there’s just too much overhang there even with a higher-resolution print.

back

The model’s now detached from its joint system, so if I’m to edit that fist I have to do it without the benefit of a weighted joint system. This is a small tweak, so I just throw a lattice around the fist and forearm instead of backing up to the beginning of step 5.

lattice fix

The fist on the second print looks much better, so I’ll go back and add some aesthetic tweaks. I’d like to roughen up the surface with some stony protrusions. Much of this can be done with Maya’s poly sculpting tools, but I add some nicely geometric gems for contrast too.

gems

The gems stuck in the Rock Frog’s back are easy to model but they don’t retain their sharp geometry in the final print. I’d like to see how this prints at a higher resolution.

back

This model and others like it are of course available for free download in The Forge. This post is the first in my series of Maker Faire Gems, wherein I’ll be blogging interesting stuff I discovered this year that might have slipped through the bigger outlets’ coverage. #staytuned

What should my first layer look like?

Your 3D printer just arrived. The nearest hackerspace is 100 miles away. You’re all ready to start printing, but all you really know about the technology is what you’ve seen on YouTube videos and breathless reports on Wired, or the Colbert Report.

They never show you the bottom of the print in any of those venues. It’s always Stanford bunny this or Colbert head that, and that’s all well and good but there’s no one around to tell you you’re doing it wrong.

first layer

I was happily printing failbottom models for months before I went to Maker Faire in Detroit and saw a proper print done by some experts.

The stringy bottom on the first two prints is mostly caused by having an off-kilter heated build platform. Make sure your heated build platform is as level as possible before you start printing.

MakerBot Replicator 1
ABS, 240° C
HBP 110° C, with painters’ tape

(These are prints of my Magic: The Gathering Fungus Tokens, available for free download in The Forge.)

MakerBot’s leveling script never seems to work perfectly for me, but since I’m printing small objects anyway I just make sure the HBP is locally level in my printing footprint. There’s no need for the corners of the platform to be 100% level if the center’s good enough.

I often start a print and let it run for a single layer to let the print heads get to their destination. Then I abort the print, remove any plastic from the HBP, and use ReplicatorG’s homing function to home the Z-axis to minimum.

(In ReplicatorG, go to Machine->Control Panel and select the Homing menu to do this.)

Then it’s a matter of twiddling the thumbscrews on the HBP until the nozzle passes MakerBot’s business card test. When you slide a business card between the nozzle and the HBP and the surface of the card just catches on the nozzle, you’ve got it.

It takes some time to get a knack for it, so don’t despair. I find it works best when the nozzle makes an indented scratch along the card’s face.

The first company to ship an auto-leveling build platform gets a fistful of cash from me.

It’s possible to get a mirror-smooth base when printing on kapton, but I’m mostly printing with ABS on painters’ tape right now. More on that in a subsequent post.