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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Electronic Phenakistoscope!

phenakistoscope

Looking for a clever way to build a Phenakistoscope? Maybe you’re more familiar with its other names; Fantoscope, Phantasmascope, or perhaps its close cousin the Zoetrope?

If you’re still scratching your head, that’s okay — they have really weird names. What we’re referring to here is a type of optical illusion that mimics movement by showing a series of still images at an offset interval — this can be achieved by looking through slots, strobing a light (like in this case) or even by the use of mirrors.

This particular Phenakistoscope is a very simple but clever design that makes use of a recycled stepper motor from a printer, a CD as the animation disk, a strip of LED lighting, a few potentiometers and an Arduino to control the strobe. It works by synchronizing the strobe frequency with the motor rotation, resulting in the image in motion effect.

Stick around after the break for a full gallery of the build and a demonstration video.

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An Animated Elf

animatedElf

Halloween receives the bulk of the attention for installation-type hacks, but [Stephen's] animated elf hack-in-progress provides the perfect example of bringing the Christmas spirit to life.

[Stephen] constructed both the background and the elf’s body from a scrap piece of plywood, drawing and painting everything by hand, and then secured the plywood with a simple 2×4 that serves as a stand. The bulk of the hack is rather simple, and reflects the longstanding technique of traditional cel animation: the non-moving portions are kept stationary and only the moving parts need to change. In this case, [Stephen's] shortcut is to insert a tablet as the elf’s face.

The tablet is a BlackBerry PlayBook, which moves the eyes around and spouts off a few Santa-related quips while animating the mouth. [Stephen] encountered a problem with the PlayBook’s 5-minute screen timeout function, and had to design a custom application to prevent the tablet from entering sleep mode while it played through the animations. His future plans are to drill a hole through the plywood and expose the tablet’s light sensor to detect when someone walks by, then have the elf spring to life in response. You can see his progress so far in the video below.

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The Rabbit’s Hole: Creative Reuse and Stop Motion Animation

rabbitshole

The folks down at The Rabbit Hole Hackerspace have been busy lately. They’ve created an amazing stop motion animation short titled “The Rabbit’s Hole”. The three-minute film documents the journey of a white rabbit through several strange lands, including the court of a “hormonally imbalanced queen”, the sewers, a PCB wasteland, and a banana jazz concert. The rest of the video is a behind the scenes view, showing the incredible amount of teamwork that went into the film’s creation.

From set building to final photography, the entire film was shot in one day.  The set was split into 8 pieces. Each piece represented a scene the rabbit would journey through in the final movie. Members of The Rabbit Hole were able to work in parallel, each designing their own section of the set. Once the photography was done, [Whisker] took over for the process of editing and sound design. Just like in Hollywood, post production took much longer than the actual shoot.

The amazing part of the video is that most of the characters and set pieces are created from The Rabbit Hole’s junkbox. Even the star of the show, a 3D printed Rabbit wasn’t immune. Many rabbits were printed for the stop motion animation process. As can be expected, there were a few failed prints. Those prints became Rabbit footed Lamps, Tables, and a rather macabre rabbit’s hand in a tray. Even the camera dolly was welded up from some scrap metal and old roller blade wheels.

We like the way the entire hackerspace was able to come together to create something greater than any one of them could have done alone. This sort of project should be a template for other hackerspaces to follow.

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Arduino particle light box generates animations from sound

arduino-particle-display

Simple tools used well can produce fantastic results. The hardware which [Gilad] uses in this project is the definition of common. We’d bet you have most if not all of them on hand right now. But the end product is a light box which seems to dance and twirl with every sound in the room. You should go watch the demo video before reading the bill of materials so that the simplicity doesn’t spoil it for you.

A wooden craft box serves as the enclosure. Inside you’ll find an Arduino board, microphone, and an 8×8 RGB module. The front cover of the project box diffuses the light using a sheet of tracing paper on a frame of foam board. It’s the code that brings everything together. He wrote his own particle system library to generate interesting animations.

If you don’t have a project box on hand this might work with an extra-deep picture frame.
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Driving a T6963C based graphic LCD

[Tom Fleet] spent the dreary weekend inside learning how to drive this T6963C based graphic LCD controller. Although this is his first time venturing away from HD44780 character displays, the availability of an Arduino library helped him go from being a newbie to coding his own animated graphics.

The hardware setup is straight-forward. The screen has a 20-pin connector and operates at 5V. We don’t see it on his protoboard, but usually these displays also need a potentiometer which serves as a voltage divider for the screen contrast. The data and control pins eat up most of the available I/O on the ATmega328 chip he used, but the I2C and SPI pins are still open and he plans a future project to make this a wireless display for his PC using one of those protocols.

As for fonts and animation, [Tom] links to several tools which will come in handy. There’s a font program that will convert Windows system fonts into a C file for use on the Arduino. The animations start with a 1:1 ratio animated graphic drawn with his favorite image editing software. He then converts those to monochrome bmp files and used bmp2c to convert each frame to a C array. After the break there’s a seven second example that would work well as a boot screen for his project.

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Stop Motion Animation Creation

PVC man stop motion animation

Stop Motion Animation has always been interesting to me since I “discovered” that one could make animated flip books by drawing each frame a little different. Fast forward 20 years or so, and computer technology has gotten to the point where this sort of thing can be done electronically quite easily and at an incredibly low price of a camera, computer, and free or paid-for software (here’s the technique using GIMP, a free, good quality photo editing tool) to put everything together.

The frames in the picture above are of my latest [PVC man] animation, which can be made with some electroluminescent lights, gloves, and some PVC pipe.  Each frame was individually photographed, and after several hours of work we had enough footage for 17 seconds of so of stop-motion animation.

Although by no means perfect, the quality of these animations has gone up dramatically from the first animations that I made using an old ENV2 camera phone. Although I was using a “custom mount” for it, it’s amazing these came out as well as they did. As with everything hacking related, this process is a constant work in progress. Check out the videos after the break for the [PVC man] video as well as one of the early ENV2-produced stop-motion shorts!

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