PhD Defense / Soutenance de Thèse Mickaël Ly

Bonjour à tous,

J'ai le plaisir de vous inviter à ma soutenance de thèse intitulée "Static inverse modelling of clothes" le Mardi 28 Septembre à 14h.

Elle se déroulera en anglais au Grand Amphi de l'Inria Grenoble, et en ligne sur le lien BBB ci-dessous.

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Dear all,

It's my pleasure to invite you to my PhD defense entitled "Static inverse modelling of clothes". The defense will be held on Tuesday, September 28th in the "Grand Amphi" at Inria Grenoble and also online on the BBB link below.

Best,

Mickaël Ly

Jury:

* Maud Marchal (Université de Rennes/IRISA) - Reviewer

* Rahul Narain (IIT Delhi) - Reviewer

* Loïc Barthe (Université Paul Sabatier/IRIT) - Examiner

* Jerôme Malick (UGA/LJK) - Examiner

* Bernhard Thomaszewski (Université de Montréal) - Examiner

* Florence Bertails-Descoubes (Inria - EP ELAN) - Supervisor

* Mélina Skouras (Inria - EP ANIMA) - Co-supervisor

* Charles Dapogny (UGA/LJK) - Guest

Visio:

Lien: https://meet.univ-grenoble-alpes.fr/b/mic-6am-93j

Code: 909579

Abstract:

This thesis deals with the direct simulation and inverse design of garments in the presence of frictional contact.

The shape of draped garments results from the slenderness of the fabric, which can be represented in mechanics by a thin elastic plate or shell, and from its interaction with the body through contact and dry friction.

This interaction, necessary to reproduce the threshold friction

occuring in such contacts, is described by a non smooth law, which, in general, makes its integration complex.

In a first contribution, we modify the so-called Projective Dynamics algorithm to incorporate this dry frictional contact law in a simple way. Projective Dynamics is a popular method in Computer Graphics that quickly simulates deformable objects such as plates with moderate accuracy, yet without including frictional contact. The rationale of this algorithm is to solve the integration of the dynamics

by successively calculating estimates of the shape of the object at the next timestep. We take up the same idea to incorporate a procedure for estimating the frictional contact law that robustly captures the threshold phenomenon.

In addition it is interesting to note that simulators developed in Computer Graphics, originally targeted at visual animation, have become increasingly accurate over the years. They are now being used in more "critical" applications such as architecture, robotics or medicine, which are more demanding in terms of accuracy. In collaboration with mechanicists and experimental physicists, we introduce into the Computer Graphics community a number of protocols to verify the correctness of simulators, and we present in this manuscript our contributions related to plate and shell simulators.

Finally, in a last part, we focus on garment inverse design. The interest of this process is twofold. Firstly, for computing equilibria, solving the inverse problem provides a "force-free" and possibly curved version of the input (called the rest or natural shape), whether it comes from a 3D design or a 3D capture, that allows to start the simulation with the input as the initial deformed shape. To this end, we propose an algorithm for the inverse design of clothes represented by thin shells that also accounts for dry frictional contact. Within our framework, the input shape is considered to be a mechanical equilibrium subject to gravity and contact forces. Then our algorithm computes a rest shape such that this input shape can be simulated without any sagging.

Secondly, it is also appealing to use these rest shapes for a real life application to manufacture the designed garments without sagging. However, the traditional cloth fabrication process is based on patterns, that is sets of flat panels sewn together. In this regard, we present in our more prospective part our results on the adaptation of the previous algorithm to include geometric constraints, namely surface developability, in order to get flattenable rest shapes.