Rigging Your 3D Models In The Real-World

Computer animation is a task both delicate and tedious, requiring the manipulation of a computer model into a series of poses over time saved as keyframes, further refined by adjusting how the computer interpolates between each frame. You need a rig (a kind of digital skeleton) to accurately control that model, and researcher [Alec Jacobson] and his team have developed a hands-on alternative to pushing pixels around.

3D Rig with Control Curves
Control curves (the blue circles) allow for easier character manipulation.

The skeletal systems of computer animated characters consists of kinematic chains—joints that sprout from a root node out to the smallest extremity. Manipulating those joints usually requires the addition of easy-to-select control curves, which simplify the way joints rotate down the chain. Control curves do some behind-the-curtain math that allows the animator to move a character by grabbing a natural end-node, such as a hand or a foot. Lifting a character’s foot to place it on chair requires manipulating one control curve: grab foot control, move foot. Without these curves, an animator’s work is usually tripled: she has to first rotate the joint where the leg meets the hip, sticking the leg straight out, then rotate the knee back down, then rotate the ankle. A nightmare.

[Alec] and his team’s unique alternative is a system of interchangeable, 3D-printed mechanical pieces used to drive an on-screen character. The effect is that of digital puppetry, but with an eye toward precision. Their device consists of a central controller, joints, splitters, extensions, and endcaps. Joints connected to the controller appear in the 3D environment in real-time as they are assembled, and differences between the real-world rig and the model’s proportions can be adjusted in the software or through plastic extension pieces.

The plastic joints spin in all 3 directions (X,Y,Z), and record measurements via embedded Hall sensors and permanent magnets. Check out the accompanying article here (PDF) for specifics on the articulation device, then hang around after the break for a demonstration video.

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Update: 3D Printed Concrete Castle Completed

After two years of dreaming, designing, and doing, [Andrey Rudenko] has finally finished 3D printing his concrete castle. We’re sure a few readers will race to the comments to criticize the use of “castle” as an acceptable descriptor, but they’d be missing the point. It’s been only three months since he was testing the thing out in his garage, and now there’s a beautiful, freestanding structure in his yard, custom-printed.

There are no action shots of the printer setup as it lays down fat beads of concrete, only close-ups of the nozzle, but the castle was printed on-site outdoors. It wasn’t, however, printed in one piece. [Andrey] churned out the turrets separately and attached them later. He won’t be doing that again, though, because moving them in place was quite the burden. On his webpage, [Andrey] shares some insight in a wrap-up of the construction process. After much experimentation, he settled on a layer height of 10mm with a 30mm width for best results. He also discovered that he could print much more than his original estimation of 50cm of vertical height a day (fearing the lower layers would buckle).

With the castle a success, [Andrey] plans to expand his website to include a “posting wall for new ideas and findings.” We’re not sure whether that statement suggests that he would provide open-source access to everything or just feature updates of his future projects.

Wooden supports for concrete bridging.
[Andrey] used wooden supports to print concrete bridges.
We hope the former. You can check out its current format as the Architecture Forum, where he explains some of the construction capabilities and tricks used to build the castle.

His next project, a full-scale livable structure, will attempt to print 24/7 (weather permitting) rather than the stop-start routine used for the castle, which turned out to be the culprit behind imperfections in the print. He’ll have to hurry, though. [Andrey] lives in Minnesota, and the climate will soon cause construction to take a 6-month hiatus until warm weather returns. Be sure to check out his website for more photos and a retrospective on the castle project, as well as contact information—[Andrey] is reaching out to interested parties with the appropriate skills (and investors) who may want to help with the new project.

[via 3ders.org]

[Thanks Brian]

THP Semifinalist: Retro Populator, A Pick And Place Retrofit For A 3D Printer

retro

A huge theme of The Hackaday Prize entries is making assembly of electronics projects easier. This has come in the form of soldering robots, and of course pick and place machines. One of the best we’ve seen is the Retro Populator, a project by [Eric], [Charles], [Adam], and [Rob], members of the Toronto Hacklab. It’s a machine that places electronic components on a PCB with the help of a 3D printer

The Retro Populator consists of two major parts: the toolhead consists of a needle and vacuum pump for picking up those tiny surface mount parts. This is attaches to a quick mount bolted right to the extruder of a 3D printer. The fixture board attaches to the bed of a 3D printer and includes tape rails, cam locks, and locking arms for holding parts and boards down firmly.

The current version of the Retro Populator, with its acrylic base and vacuum pen, is starting to work well. The future plans include tape feeders, a ‘position confirm’ ability, and eventually part rotation. It’s a very cool device, and the ability to produce a few dozen prototypes in an hour would be a boon for hackerspaces the world over.

You can check out a few videos of the Retro Populator below.


SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize. 

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Make Your Own Mac Pi For Some Desktop Nostalgia

Mac Pi

Do you miss your Mac Classic? Well if you’re looking for a fun little project, why not build yourself a Mini Mac Pi that emulates Mac OS 7?

It’s a fairly simple project that makes use of the Raspberry Pi B, a 320×240 2.8″ touchscreen LCD (the PiTFT), a lithium-ion battery, a buck-boost circuit and of course, a power switch. The cute enclosure is made by 3D printing, and all the files are available on Thingiverse – they’ve been sliced up in a way that they will be printable on most consumer printer bed sizes.

Once everything is assembled, you’ll need to run Mini vMac alongside Raspbian in order to run Mac OS 7. There are a few caveats though — The original resolution is 512×342, so there’s a bit of screen clipping that occurs. There’s also minor application support, but for the purpose of nostalgia, we think the included selection is more than enough to satisfy most memories.

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THP Semifinalist: Theta Printer

thetaThe early 3D printers of the 80s and 90s started off as cartesian bots, and this is what the RepRap project took a cue from for the earliest open source 3D printer designs. A bit later, the delta bot came on the scene, but this was merely a different way to move a toolhead around build plate. We haven’t really seen a true polar coordinate 3D printer, except for [Tyler Anderson]‘s incredible Theta printer.

[Tyler]‘s theta printer is designed to print in as many different materials as possible, without the reduction in build volume that comes with multiple toolheads on more traditional printers. It will be able to lay down different colors of plastic in a huge build volume, and even some of the weirder filaments out there, all in a single print.

The theta printer is based on a polar coordinate system, meaning instead of moving a hot end around in the X and Y axes, the build plate rotates in a circle, and the extruders move along the radius of the circle. This spinning, polar coordinate printer is the best way we’ve seen to put multiple extruders on a printer, and has the added bonus of being a great platform for a 3D scanner as well.

With four extruders, four motors to control the position of each extruder, a rotation motor, and the Z axis (that’s 10 steppers if you’re counting), this is very likely the greatest number of motors ever put in a 3D printer. Most electronics boards don’t support that many stepper drivers, and the one that will won’t be ready for the end of The Hackaday Prize. Right now, [Tyler] is running a fairly standard RAMPS board, running two extruders and R axes in parallel. Still, it’s good enough for a proof of concept.

One interesting aspect of [Tyler]‘s design is something even he might not have realized yet: with a single bed and four extruders, he’s effectively made a 3D printer geared for high-volume production; simply by printing the same part with all the extruders, he’s able to quadruple the output of a 3D printer with the same floor space as a normal one. This may not sound like much, but when you realize Lulzbot has a bot farm producing all their parts, the Theta printer starts to look like a very, very good idea.

Videos of [Tyler]‘s Theta below.


SpaceWrencherThe project featured in this post is a semifinalist in The Hackaday Prize.

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3D Printing a Beautiful Prosthetic Hand for a Stranger

3D Printed Prosthetic Hand

Here’s a story that made us feel all warm and tingly on the inside. [Evan Kuester] is currently studying his Masters in Architecture with a specialty in digital fabrication. His program has access to some nice 3D printers, and he was itching for a good project to use them for. Why not a 3D printed prosthetic hand?

He got the idea after noticing a fellow student on campus who was missing her left hand, and did not have any kind of prosthetic. Eventually he worked up the nerve to introduce himself to her and explain his crazy idea. She thought it was brilliant.

Using Rhino, [Evan] began modeling the prosthetic hand using a plugin called Grashopper. He wanted the hand to be functional as well as aesthetically pleasing, so he spent quite a while working with [Ivania] to make it just right. His first prototype, the Ivania 1.0 wasn’t quite what he imagined, so he redesigned it to what you see above. It’s a beautiful mixture of engineering and art, but unfortunately the fingers don’t move – perhaps an improvement for version 3.0? Regardless of functionality, [Ivania] loves it.

Oh, and [Evan] and [Ivania] are close friends now — in case you were wondering.

[via Make]

Homemade Nerf Blasters With 3D Printed Parts

esltcollagesuperawesome

This spectacular bullpup nerf gun was developed by the guys over at Mostly Harmless Arms. It is complete with 3D printed parts in a variety of colors. The Extension Spring/Latex Tubing (ESLT) Blasters were based off of [Kane]‘s snapoid trigger design with 1/4″ aluminum for the plunger rods which worked out really well. [Prince Edward] adapted [Kane]‘s work and modified it with 3D printing in mind. The original post from 2012 gave an in-depth look into where the idea started.

The documentation for all the printed part files and high quality photos can be found on Nerfhaven. It is really nice to see such a clean design that can be fashioned together on a relatively small budget. This makes these playful nerf blasters easy to duplicate, allowing for a full out office war. Granted, access to a 3D printer is needed, but additive manufacturing devices are getting more and more common these days. Now it’s just a matter of seeing how well they work, which can be deduced from the videos after the break:

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