Date: 11 August 15
Headline: This 4D scanner captures your unique bodily ‘jiggle’ by Liat Clark
Source: http://www.wired.co.uk/news/archive/2015-08/11/modelling-body-fat-jiggle-in-4d
The future avatars we embody will show every lump, bump and jiggle of our soft human flesh – and you have tech to thank.
A team at the Max Planck Institute for Intelligent Systems (MPI-IS) has developed what it is calling “the world’s first high resolution 4D body scanner and software”, just so our soft tissue can be more accurately mapped and replicated.
The system created by Atlanta-based 3dMD uses 66 cameras and projectors to shine light on a body being scanned. The idea is to look at depth (including every crease and crevice) and create “high-speed ‘4D movies’ of 3D body shape”. It does this by capturing 150,000 3D points on the body 60 times a second. The fourth dimension (time) allows it to record how the body deforms as it moves. Or, as MPI-IS director Michael Black eloquently points out, how it “jiggles”.
“Everybody jiggles. We may not like it, but how we jiggle says a lot about who we are. Our soft tissue (otherwise known as fat and muscle) deforms, wobbles, waves, and bounces as we move.
“These motions may provide clues about our risk for cardiovascular disease and diabetes. They also make us look real. Digital characters either lack natural soft-tissue motion or require time-consuming animation to make them believable.”
The system is very similar to traditional motion capture used in the gaming industry, but harnesses a much greater number of data points.

The software that makes use of all this data, Dyna, turns those captured data points into 3D meshes that morph and change over time as the subject moves. You can see the results of this process in the embedded video, where the super realistic animations track real bodies Ken and Barbie-style — sans genitalia — for the sake of our eyes.
Machine learning algorithms were used to train Dyna using more than 40,000 scans of ten people with different body mass indexes. These were built on top of a generic 3D model of the human body, based on an average shape. “We learn how soft-tissue motion causes mesh triangles to deform relative to a base 3D body model,” the MPI-IS team explains in a paper on the technology. The team found the body tissue moved uniquely depending on a subject’s body shape, or BMI. Dyna’s role was to learn from this data and begin to predict what movement (read: wobble, flop, jiggle) would follow any given preceding motion.
“Dyna uses a second-order auto-regressive model that predicts soft-tissue deformations based on previous deformations, the velocity and acceleration of the body, and the angular velocities and accelerations of the limbs,” the team explains. “Dyna realistically represents the dynamics of soft tissue for previously unseen subjects and motions.”
The aim of this development is obviously not to body shame us all, but to give animators new tools based on robust mathematical models to create realistic characters — or alternatively, adapt realistic predictions produced by Dyna to create more grotesque interpretations for certain characters.
Beyond the obvious commercial uses, the MPI-IS team is adamant that the tech has a huge part to play in healthcare, and even the clothing industry. If the model is improved and takes into account what lies beneath the skin, it could be used as part of a routine doctor’s check-up, Black suggests. “How your fat jiggles provides information about where it is located and whether it is dangerous.” This could be part of a wider analysis checking on things like heart disease or diabetes risk, without the need for lengthy or invasive tests.
MPI-IS also suggests uses for the makers of compression garments — they will be able to use Dyna to predict how the body will move when it is donning the articles in question. The team also predicts it could be useful for capturing “the static effects of gravity and other forces”.