Press Release

DRAW, DESIGN, ACTION: NEW METHOD AUTOMATICALLYCOMPUTES REALISTIC MOVEMENT WITH FRICTION FROM 3D DESIGNTOKYO, Japan, 28 November 2018 – Simulating any 3D surface or structure—from tree leaves and garments
to pages of a book—is a computationally challenging, time-consuming task. While various geometric tools
are available to mimic the shape modeling of these surfaces, a new method is making it possible to also
compute and enable the physics—movement and distortion—of the surface and does so intuitively and withrealistic results.
Researchers from Inria, the French National Institute for computer science and applied mathematics, havedeveloped a novel algorithm that computes the shape of the surface at rest, that is, without any external
force, and when this shape is deformed under gravity, contact and friction, it precisely matches the shape theuser has designed.
“Imagine you want to create a fancy garment on a 3D character. With our method, you can freely design thisgarment directly in 3D, around the character. You don't have to care about physics, but just about the shape,includingthefoldsandwrinkles, that you would liketo see at the final stage,”
explains Florence BertailsDescoubes,

scientificsupervisor of the work and a
researcher at INRIA. “Onceyou’ve

completedmodeling,ourautomaticallythealgorithm
converts

the geometric cloth into aphysical one.”

Without inversion (left), the hat sags under gravity, losing its intended style andpartially covering the face of the character. In contrast, the inverse method
automatically infers a natural shape of a thin elastic shell simulator such that a stableequilibrium matches the input geometry.

Users draw or design any 3D surface utilizing their preferred geometric tools and can then turn to the newcomputational method to convert the surface into a physical object, and onethat may or may not make contact with other surfaces.
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Bertails-Descoubes collaborated on the work with her PhD students Mickaël Ly and Romain Casati and Inria
colleagues Melina Skouras and Laurence Boissieux, and the team will present at SIGGRAPH Asia 2018 in Tokyo
4 December to 7 December. The annual conference features the most respected technical and creative
members in the field of computer graphics and interactive techniques, and showcases leading edge researchin science, art, gaming and animation, among other sectors.
Many geometric tools exist to perform accurate modeling of shapes with flexibility given to the user. Given
the example of modeling clothing around a 3D character, the researchers’ method provides a simpler way forthe clothing to mimic movement on the animated character, automatically computing for gravity andfrictional contact with an external body.
“For instance, if a user draws a 3D skirt on an animated character, our method will automatically shrink therest shape and tighten it at the waist, to compensate for gravity which ‘wants’ to pull the item downwards,”
notes Bertails-Descoubes. The team’s method also enables users to change the physical properties of thegarment designed, i.e. making it out of linen instead of cotton. In turn, the cloth will behave differently,appearing softer, for instance, for lightweight cotton and will appear to have less friction with the body.
The scientists note that “the major difficulty in this kind of inverse problem stems from the fact that it is highly
nonlinear. This complexity is particularly exacerbated by the presence of contact and dry friction, which wasnever explicitly accounted for in previous studies. It is thus challenging to design a robust algorithm able tofind a valid rest shape for a large variety of different scenarios.”
The researchers provided several examples in the paper, showcasing their algorithm’s performance on 3D
animated designs. Included in the paper are two hat examples—noted as ‘floppy hat’ and ‘beret’—which are
posed on a human head through contact and friction. Without the researchers’ inversion method, the floppy
hat sags, completely losing its original style and partly covering the face of the animated character. In contrast,
after running the new algorithm, the hat preserves its original style and realistically flip-flops with themovement of the character. The beret example produced similar realistic results after applying the team’s
method—the beret correctly remained inflated and posed on the head. When ‘wind’ is applied to the design,
the beret slides with the movement but does not fall completely off the head, exemplifying the algorithm’s
ability to realistically simulate the physics involved.
In future work, the team will focus on making their algorithm work faster and be adapted to the creation ofreal garment patterns.
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For the authors’ paper, titled “Inverse Elastic Shell Design with Contact and Friction”, visit the team’s projectpage.
To register for SIGGRAPH Asia, and for more details of the event, visit http://sa2018.siggraph.org.
– end –Notes to editors:•For more information on the Technical Papers Program, click here.

•For media accreditation to SIGGRAPH Asia 2018, please register here.

About SIGGRAPH Asia 2018
The 11th ACM SIGGRAPH Conference and Exhibition on Computer Graphics and Interactive Techniques in Asia
(SIGGRAPH Asia 2018) will be held in Tokyo, Japan at the Tokyo International Forum from 4 to 7 December
2018. The annual event held in Asia attracts the most respected technical and creative people from all over
the world who are excited by research, science, art, animation, gaming, interactivity, education and emerging
technologies.
The four-day conference will include a diverse range of juried programs, such as the Art Gallery, Computer
Animation Festival, Courses, Emerging Technologies, Posters, Technical Briefs, Technical Papers and Virtual &Augmented Reality. A three-day exhibition held from 5 to 7 December 2018 will offer a business platform forindustry players to market their innovative products and services to the computer graphics and interactive
techniques professionals and enthusiasts from Asia and beyond. For more information, please visit
http://sa2018.siggraph.org. Find us on: Facebook, Twitter, Instagram and YouTube with the official event
hashtag, #SIGGRAPHAsia.

About ACM SIGGRAPH
The ACM Special Interest Group on Computer Graphics and Interactive Techniques is an interdisciplinary
community interested in research, technology, and applications in computer graphics and interactivetechniques. Members include researchers, developers, and users from the technical, academic, business, andart communities. ACM SIGGRAPH enriches the computer graphics and interactive techniques community
year-round through its conferences, global network of professional and student chapters, publications, andeducational activities. For more information, please visit www.siggraph.org.

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About Koelnmesse
Koelnmesse Pte Ltd is one of the world's largest trade fair companies. Its more than 80 trade fairs andexhibitions have the broadest international scope in the industry, as 60 percent of the exhibitors and 40
percent of the visitors come from outside Germany. The Koelnmesse events include leading global trade fairs
for 25 sectors, such as Imm Cologne, Anuga, IDS, INTERMOT, Interzum Cologne, Photokina, Gamescom, andthe International Hardware Fair Cologne. Koelnmesse is ACM SIGGRAPH’s event organizer for the last 10editions of SIGGRAPH Asia. For more information, please visit www.koelnmesse.com.sg.

Media Contacts
Hitoshi Kasai
Head of Communications, SIGGRAPH Asia 2018
MIACIS Associates
hitoshi.kasai@siggraph.org
Jamie Huang
Marketing & Media Partnerships, SIGGRAPH Asia 2018
Koelnmesse Pte Ltd
jamie.huang@siggraph.org

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