Armature (computer animation)

An armature is the name of the kinematic chains used in computer animation to simulate the motions of virtual human or animal characters. In the context of animation, the inverse kinematics of the armature is the most relevant computational algorithm.
There are two types of digital armatures: Keyframing (stop-motion) armatures and real-time (puppeteering) armatures. Keyframing armatures were initially developed to assist in animating digital characters without basing the movement on a live performance. The animator poses a device manually for each keyframe, while the character in the animation is set up with a mechanical structure equivalent to the armature. The device is connected to the animation software through a driver program and each move is recorded for a particular frame in time. Real-time armatures are similar, but they are puppeteered by one or more people and captured in real-time.
Inside of every puppet stop motion character is an Armature. Armature fills two main functions, It must move in a human-like manner in order to give life to character animation. The inner skeletal structure must be close to human-like as possible this includes having joint and finger flexibility. Human movements also involve spinning at the elbows, knees, shoulders and hips in order to bend down and pick up something from the ground. The second job of an armature is to not move. It is necessary that armature does not move, it must have some stiffness when positioned into place. “you don't want to be in the middle of a shoot with several minutes can pass by between each shot and have the puppets slowly drooping between one shoot and the next” (Justatinyamount, 2018). In built geometric movement can extend into the hands and feet. Even facial movements are available in some armature figures. 
“There are two types of digital armatures: Keyframing (stop-motion) armatures and real-time (puppeteering) armatures” (Wikipedia Article). Both Key framing and of wax, clay or plaster. Historically, armatures were made of chicken wire, wood and many pounds of clay, making them very heavy” (Computer Animation Complete, Parent, Rick).
Real-time puppeteering.
Real-time Puppeteering, simply means that the character skeleton is controlled by a human animator, by “simple mapping between a hardware controller (such as a gamepad, a wiimote, a custom puppet controller, or even your body with a kinect-based system) and the character’s 3D animation armature” (Three Real-Time Animation Methods, Hancock, Terry). Because of the nature of Puppeteering devices there is no attempt to control “Natural Motion”, you just simply manipulate the Digital puppet to do what you want. It takes some skill to do this like puppeteering, “You can take advantage of the puppeteer's skills, because these guys are masters. It’s just amazing seeing them put their hand in a puppet and it just comes to life” (“Computer Animation Complete”, Parent, Rick). Digital Real-Time Armature main difference, “It is controlled or we can say it is being puppets by people and the motions are captured in real time. This type of animation is used basically for 2D or 3D figures and objects created by using some 2D and 3D animation software. This type of animation armature is used for mainly filmmaking and Television production purposes. The film made using this technique is captured in real time by making the character move and capturing its live performance for the film” (Virtualschooldek.com). Motions are recorded with digital software. Software such as Blender, “Blender is the free and open source 3D creation suite. It supports the entirety of the 3D pipeline—modeling, rigging, animation, simulation, rendering, compositing and motion tracking, video editing and 2D animation pipeline” (https://www.blender.org). This software allows the registering of data from Digital Armatures.
Types of armatures build.
Action Figures can also be converted into Armatures, for instance, TV shows such as Robot Chicken use modified forms of Armature Action Figures for their show. The most common toys for Armature are Lego’s, “It’s easy to see why they look great, they stay where you put them and you can move them around a reasonable amount” (Youtube Video “The 3 main types of Armature”). The only setback is their range of motion so this calls for them to be modified, so aluminium wire is inserted inside of them in order for joints to have a wider range of motion that seems organic to the character. In the “Lego Movie”, the majority of the characters were Digital Armatures. Director Chris Miller, even used his childhood Lego Toy as the main character for the entire movie; “Chris Miller literally brought his broken space man toy which he had since he was a little kid … That’s the level of detail and realism we wanna create (Film). Armatures was not the only method used but it was a hybrid effort of techniques in order to achieve the final product. Modifications can be done on figures such as LEGOs, such as installing wire through the character in order to have a fuller range of motion. Bringing life into toys is nothing new shows such as “Robot Chicken” implement, Action Figure Armatures in order for iconic doll super heroes to appear on the show. 
Twisted Wire Armature is another cost-effective method used by animators, the only problem with this type of method is that joints are not strong and will lead to a drooping figure over time. Ball and Sockets Armatures have been the traditional method in which figures have been built, with a method such as this the plates inside the puppet are easily adjustable for stiffness. Balls and sockets can often be bulky so a Hybrid method between Twisted Wire Armature and Ball and Socket Armatures are created by animators in order for characters to move fluidly throughout the body. Ball and Socket Armature Kits are available for purchase, but these figures are often expensive. Descriptions for Kits include, “The Standard Armature Kit comes complete with everything you need to make your own armature. It is easy assembled and has been designed to meet most character designs. As well as double jointed ball and socket joints” (Animation Supplies Website).
How armatures work.
“Puppeteering armatures are very similar to keyframing armatures, expect the motion is captured in real time as performed by one or more puppeteers.”( Parent, Rick and Computer Animation Complete) Through the use of tracking markers, sensors, hand controls, and animation software, “puppeteers” are able to produce an animated performance in real time. Through a live performance conducted in real time, sensors and tracking markers attached to the performer help translate their body movements into the actions and expressions that the 3D digital armature replicates in real time. Rather than using an armature model with joints and built in sensors, this type of “real time” animation relies on a live performer and the movements they conduct to simulate the actions the 3D digital armature will follow. Aside from the sensors attached to the live performer used to record their body movements, face trackers are also used to record the performers facial expressions in real time as well . “ The most popular are the real-time optical face trackers, consisting of a camera that is placed in a structure attached to the performer’s head so that it moves with the performer. The device captures the motion of small markers placed in different areas of the face.”( Understanding Motion Capture for Computer Animation and Menache, Alberto). Along with the body sensors these facial trackers allow the puppets to capture the real time expression and digitally animate it. However the application of facial tracks through real time simulations has a limit when it comes to its range of detail. “Unfortunately, these are 2D devices that cannot capture certain motions such as puckering of the lips, so the data is all in one plane and not very realistic. Three-dimensional facial motion data can be captured with an optical system using two or more cameras, yielding a much better result, but not in real time.” ( Understanding Motion Capture for Computer Animation and Menache, Alberto). Aside from the use of live performers in real time armatures, digital armatures made of joints, and sensors can also be used to simulate animated movement in real time. “The last commercially available example of a digital armature was the Monkey 2 by Digital Image Design in New York City. It was modular, so it could be assembled in different joint configurations.”( Understanding Motion Capture for Computer Animation and Menache, Alberto) With modular capabilities embedded in the armature the puppeteers are allowed to maneuver the figure and transport its actions digitally. “Both stop-motion and real time types consist of a series of rigid modules connected by joints whose rotations are measured by potentiometers or angular sensors. The sensors are usually analog devices, but they are called digital because the resulting readings are converted to digital signals to be processed by the computer system. These armatures are typically modular in order to accommodate different character designs.”( Understanding Motion Capture for Computer Animation and Menache, Alberto) The modular design allows for these digital armature models to simulate movements that in an animated environment resemble those of a human or animal. “ The first-generation Monkey had a fixed configuration, which made it unusable for any non humanoid applications.”(Understanding Motion Capture for Computer Animation and Menache, Alberto) A modular armature helps overcome this problem and create a solid baseline that is capable of various movements and extensions. Now depending on the package contents that come with the digital armature model itself the price may vary. “ The typical cost for a 39-joint Monkey 2 setup was approximately $15,000, which included all the necessary parts as well as driver software for most well known animation packages.”(Understanding Motion Capture for Computer Animation and Menache, Alberto) Both the live performance and digital armature real time animation methods convert to digital formats allowing the puppeteers different ways to produce and create an animated visual. Through real time armatures “Motus Digital” is able to bring their creations to life and implement interactive settings within their animations. Through real time armature this company creates “Larry the Zombie”, an interactive character that they use in their business ventures. “This year Larry will take our Real-Time technology to the next level by attending the show himself, in search of “The Next Big Thing”. He will interview panelists, share his schedule and report what’s going on and do whatever it takes to find the next big thing. Unlike Elf Hotline that takes place at the “North Pole”, Larry lives in the real world and is keen on pop culture and world events. Although the Real-Time interviews will be conducted via Skype, Larry’s character will be composited into the shot giving Larry a real presence at this years South by SouthWest.”( Motus Digital) Through real time armature this company shows how creative and interactive content can be created and shared with a larger audience.
Keyframing (stop motion).
Stop motion animation is captured one frame at a time and when they are played back it looks like movement. It is achieved by taking a picture of each individual frame and then editing it together in whatever software you may prefer. The more fluid you want the movements to look, the more frames you would need. Stop motion works just a flipbook but in a digital format. In this analogy frames would be equivalent to the pages in a flipbook, the more pages you have the more organic the movements look. Stop motion animation can be integrated into live action films or be completely animated. Live action movies like “The Terminator”(1984) and “RoboCop” (1987) both had stop motion sequences.
Tim Burton: Armature Influence.
Tim Burton, a graduate from CalArts in southern california, was well aware of the stop motion techniques available to him. CalArts, founded by Walt Disney, in 1961 was innovating computer applications of armatures and other forms of computer designs. A popular example of stop motion are Tim Burton movies, his animated ones of course. “Nightmare before Christmas”, “Corpse Bride”, “Coraline”, etc. A lot goes into making a stop motion film with the quality of a Tim Burton one. Everything you see on screen was made by someone in the crew. The set was built, the puppets were hand made and every single frame was an individual picture taken. On a behind the scenes video for the movie “Frankenweenie” one of the crew members shows one of their exposure sheets which is a stop motion equivalent to a shot list. The frames are broken down in phonetics (the sound a letter makes) which means it takes multiple frames to even make one word that a character may say. The crew member has to shape the puppet's mouth so that it matches every sound made in every word that the voice actor says in the dialogue. It is also mentioned in the video that even the smallest action such as blinking requires the puppets eyelids to be replaced each time. In the behind the scenes video for the movie “Coraline” crew members show how movement can look so fluid in stop motion by explaining the process of rigging. Rigging in stop motion is when someone uses mechanics like winding or pulling to propel a puppet or set piece through space. For example an animator may put an object on a piece of wire and move the wire in different positions and then edit the wire out in post production. 
 Tim Burton’s love for the old age technique of stop-motion animation, which has contributed a big part to its success is due to his obsession with the simple idea that this specific technique could really bring to life ideas that otherwise would be impossible. “The animation helped viewers identify with something that could not possibly exist.” Burton’s need to use stop-motion animation was due to the idea that “it could bring something purely imagined to vivid life in a way that 2-D animation couldn’t.” This was amplified through his exploration with other works of art such as James Whale’s Frankenstein, which helped focus on those ideas of monsters and his need to create them in his life. There is no question that Burton did exactly that with his work in The Nightmare Before Christmas which brought this technique back into the limelight. Although Burton worked with animators like John Lasseter who made Toy Story happen with computer animation he never lost focus on stop-motion animation. This helped him create amazing films such as Corpse Bride and remake of his 1984 short film Frankenweenie. To no surprise Burton’s original commercial for MoMA’s exhibition was made with the age-old technique of stop-motion animation to honor the amazing creator. Although Tim Burton was not the original creator of this technique he was honored in part of the series to help represent the influence that his films have had on the technique. Other creators who have come before him in the field of stop-motion animation are Harryhausen “the subject of a MoMA retrospective—Ray Harryhausen: Special Effects (May 28–September 1, 1981)”. Harryhausen who trained under Willis O’Brien “creator of effects in King Kong (1933) and Mighty Joe Young (1949)”.
Wes Anderson: Armature Animation Influence.
Wes Anderson is a director who primarily makes live action films but he does have two stop motion animated movies “Fantastic Mr. Fox” and “Isle of Dogs”. Although these films are animated they still show Wes Anderson’s signature style. In a behind the scenes video for the movie “Isle of Dogs” it’s shown that animators used actual movement as a reference. They had real dogs on set so that they could have something to base their animation on. Also animators would film themselves walking or doing any action that they need to animate and then they would look at it when animating a human puppet. This helped them to make action look more fluid and realistic because they were using themselves as a reference.
History of Stop Motion.
Stop motion started in the late 1800s. The first ever Stop-motion film was released in 1898 “The Humpty Dumpty Circus” created by J. Stuart Black and Albert E. Smith. It was popularized by the animator Willis O’ Brien who mixed stop motion with live actors. His best known work was “King Kong”(1933). In 1940 animator George Pal developed a technique called “replacement animation”. Instead of using clay or any other malleable material to change the puppet he created multiple wooden heads, each with a different facial expression and replaced the heads when conveying different emotions. In 1944 George Pal won an Oscar for this technique. In 1955 Art Clokey, a pioneer in claymation (stop motion with clay figures), created “Gumby” for “The Howdy Doody Show”. In 1961 he also created the children’s show “Davey and Goliath” which was sponsored by the Lutheran Church.
Claymation.
Claymation is a very popular type of Stop motion animation used by many different creators. Pioneered by Art Clokey as mentioned in the previous section, Claymation is still used by modern day animators. It was used by Tim Burton and Henry Selick in films like “ParaNorman” “Coraline” and “The Nightmare before Christmas”. Director and animator Nick Park also used claymation in all of his “Chicken Run” and “Wallace and Gromit” movies. Rankin/Bass Productions Inc. also used claymation in Christmas special movies like “Rudolph the Red-Nosed Reindeer”(1964) and “Jack Frost”(1979) both in which air on the network NBC. Although all of these films use clay and stop motion animation, they each have their own unique look and style. Claymation has evolved throughout the years because all creators have their own vision and clay is so malleable that it could make endless styles of characters and scenery. moving clay. In this technique pieces of clay are moulded to create characters and based on the imagination of the animator, a story is unfolded. There are oil based and water based clays available. Sometimes the clay is moulded into free forms or filled up in a wire like structure called armature. The animated characters are kept in a set and with only short movements, the whole scene is film. Famous examples of this technique being used are, Missing Link by Chris Butler, Kubo and the two strings by Travis Andrew Knight, Coraline by Charles Henry Selick, The Boxtrolls by Graham Annable, Anthony Stacchi.
References.
Sources 
https://www.techopedia.com/definition/109/stop-motion-animation
https://www.youtube.com/watch?v=VUFkjD9_QPQ
https://www.youtube.com/watch?v=jXqqd0ZBEMA
https://www.youtube.com/watch?v=mZcZfES8EEE
https://www.thewrap.com/a-timeline-of-stop-motion-animation-history-from-a-trip-to-the-moon-to-isle-of-dogs-photos/
Menache, Alberto. Understanding Motion Capture for Computer Animation. Morgan Kaufman, Elsevier Publication. Google Books, https://books.google.com/books?id=bgkzx4q88ScC&pg=PA30&lpg=PA30&dq=modular+armatures+for+real+time+animation&source=bl&ots=voG7seE378&sig=ACfU3U3YD_EYdfDPdJpR7yl1na0Govdnkw&hl=en&sa=X&ved=2ahUKEwjf9ODPg_joAhXYIDQIHWDwDDoQ6AEwAnoECAkQAQ#v=onepage&q=modular%20armatures%20for%20real%20time%20animation&f=false
“What is Real Time Animation”. Motus Digital, http://motusdigital.com/real-time-animation.htm
Parent, Rick, et.al.Computer Animation Complete: All-in-One: Learn Motion Capture, Characteristic, Point-Based and Maya Winning Techniques. Morgan Kaufmann Elsevier, Google Books, https://books.google.com/books?id=bgkzx4q88ScC&pg=PA30&lpg=PA30&dq=modular+armatures+for+real+time+animation&source=bl&ots=voG7seE378&sig=ACfU3U3YD_EYdfDPdJpR7yl1na0Govdnkw&hl=en&sa=X&ved=2ahUKEwjf9ODPg_joAhXYIDQIHWDwDDoQ6AEwAnoECAkQAQ#v=onepage&q=modular%20armatures%20for%20real%20time%20animation&f=false
Animation Supplies, www.animationsupplies.net/standard-armature.html.
https://www.moma.org/explore/inside_out/2010/04/07/crude-elegance-stop-motion-animation-and-tim-burton/
Parent, Rick. Computer Animation Complete: All-in-One: Learn Motion Capture, Characteristic, Point-Based, and Maya Winning Techniques. Morgan Kaufman Is an Imprint of Elsevier, 2010
Sharma, Deepali, and Deepali Sharma. “Animation, VFx, Creative Skills, Digital Marketing, Online Personality Development.” Animation, VFx, Creative Skills, Digital Marketing, Online Personality Development, 2 Nov. 2016, virtualschooldesk.com/armature-meaning-importance-animation/..
Hancock, Terry. “Three Real-Time Animation Methods.” Three Real-Time Animation Methods: Machinima, Digital Puppetry, and Motion Capture, freesoftwaremagazine.com/articles/three_real_time_animation_methods_machinima_digital_puppetry_and_motion_capture/.
Foundation, Blender. “Home of the Blender Project - Free and Open 3D Creation Software.” Blender.org, www.blender.org/.
Craig, G. [Just a Tiny Amount]. (2018, May 28). The Three Main Types of Armature [Video]. Youtube. https://www.youtube.com/watch?v=H6b3lRadcwE&t=1s
[Warner Bros. Pictures]. (2015, January 26). The Lego Movie Creating The Bricks [Video]. Youtube. https://www.youtube.com/watch?v=po0dmHhgsxU