Research

My research lies in the area of computer graphics, more specifically in physically based simulation of deformable models and fluids. I am particularly interested in adaptive models to allow the expression of complex effects and drastically reduce computational cost.

In computer graphics, the physical phenomena simulated for the creation of animations, video games or the design of objects are more and more complex:First, in terms of the computational cost, the scale of the simulations can be extremely important ; Then, in terms of the complexity of the phenomena themselves, which require the models to be able to change their state and shape. This growing complexity introduces new challenges in order to offer control on these large scale simulations to the user. In many cases, this control is reduced to a trial-and-error process in order to determine the parameters of the simulation which best meet the objectives of the user. In this thesis, we propose three techniques to tackle these challenges. First, we introduce a new adaptive model which allows the reduction of the computational cost in Lagrangian simulations of particles. In contrast with re-sampling strategies, the number of degrees of freedom remains constant throughout the simulation. Therefore, the method is simpler to integrate into an existing simulator and the memory consumption remains constant, which can be an advantage in an interactive context. Then, we propose an algorithm which allows the detailed cutting of thin deformable objects. Our method relies on a dynamic update of the shape functions associated to the degrees of freedom, which therefore allows the use of a very low number of degrees of freedom while performing detailed topological changes. Finally, we focus on the control of animations of liquid and take inspiration from interactive methods of shape editing in the field of 3D modeling. We introduce a system where the user directly edits the result of the simulation: a sequence of meshes representing the surface of the liquid. We propose selection and editing spatio-temporal tools inspired from static shape sculpting software.

[Thesis (PDF)] [Slides PDF | Github]

Publications

Teaser Space-time sculpting of liquid animation
Pierre-Luc Manteaux*, Ulysse Vimont*, Chris Wojtan, Damien Rohmer, Marie-Paule Cani, *joint first authors
Motion In Games 2016
[Paper (PDF)] [Movie (MP4, 20.8MB)] [Bibtex] [Project Page]
Abstract: We propose an interactive sculpting system for seamlessly editing pre-computed animations of liquid, without the need for any re-simulation. The input is a sequence of meshes without correspondences representing the liquid surface over time. Our method enables the efficient selection of consistent space-time parts of this animation, such as moving waves or droplets, which we call space-time features. Once selected, a feature can be copied, edited, or duplicated and then pasted back anywhere in space and time in the same or in another liquid animation sequence. Our method circumvents tedious user interactions by automatically computing the spatial and temporal ranges of the selected feature. We also provide space-time shape editing tools for non-uniform scaling, rotation, trajectory changes, and temporal editing to locally speed up or slow down motion. Using our tools, the user can edit and progressively refine any input simulation result, possibly using a library of pre-computed space-time features extracted from other animations. In contrast to the trial-and-error loop usually required to edit animation results through the tuning of indirect simulation parameters, our method gives the user full control over the edited space-time behaviors.
Teaser Adaptive Physically-Based Models in Computer Graphics
Pierre-Luc Manteaux, Chris Wojtan, Rahul Narain, Stephane Redon, François Faure, Marie-Paule Cani
Computer Graphics Forum 2016
[Preprint (PDF)] [Bibtex] [Project Page]
Abstract: One of the major challenges in physically-based modeling is making simulations efficient. Adaptive models provide an essential solution to these efficiency goals. These models are able to self-adapt in space and time, attempting to provide the best possible compromise between accuracy and speed. This survey reviews the adaptive solutions proposed so far in computer graphics. Models are classified according to the strategy they use for adaptation, from time-stepping and freezing techniques to geometric adaptivity in the form of structured grids, meshes, and particles. Applications range from fluids, through deformable bodies, to articulated solids.
Teaser Interactive Detailed Cutting of Thin Sheets
Pierre-Luc Manteaux, Wei-Lun Sun, François Faure, Marie-Paule Cani, James F. O'Brien
Motion In Games 2015
[Paper (PDF)] [Movie (MP4, 2.67MB)] [Bibtex] [Project Page]
Abstract: In this paper we propose a method for the interactive detailed cutting of deformable thin sheets. Our method builds on the ability of frame-based simulation to solve for dynamics using very few control frames while embedding highly detailed geometry - here an adaptive mesh that accurately represents the cut boundaries. Our solution relies on a non-manifold grid to compute shape functions that faithfully adapt to the topological changes occurring while cutting. New frames are dynamically inserted to describe new regions. We provide incremental mechanisms for updating simulation data, enabling us to achieve interactive rates. We illustrate our method with examples inspired by the traditional Kirigami artform.
Teaser Interactive procedural simulation of paper tearing with sound
Thibault Lejemble, Amélie Fondevilla, Nicolas Durin, Thibault Blanc-Beyne, Camille Schreck, Pierre-Luc Manteaux, Paul G. Kry, Marie-Paule Cani
Motion In Games 2015
[Paper (PDF)] [Movie (MP4, 20.56MB)] [Bibtex] [Project Page]
Abstract: We present a phenomenological model for the real-time simulation of paper tearing and sound. The model uses as input rotations of the hand along with the index and thumb of left and right hands to drive the position and orientation of two regions of a sheet of paper. The motion of the hands produces a cone shaped deformation of the paper and guides the formation and growth of the tear. We create a model for the direction of the tear based on empirical observation, and add detail to the tear with a directed noise model. Furthermore, we present a procedural sound synthesis method to produce tearing sounds during interaction. We show a variety of paper tearing examples and discuss applications and limitations.
Teaser Exploring the Use of Adaptively Restrained Particles for Graphics Simulations
Pierre-Luc Manteaux, François Faure, Stéphane Redon, Marie-Paule Cani
VRIPHYS 2013
[Paper (PDF)] [Movie (FLV, 13.2MB)] [Bibtex] [Project Page]
Abstract: In this paper, we explore the use of Adaptively Restrained (AR) particles for graphics simulations. Contrary to previous methods, Adaptively Restrained Particle Simulations (ARPS) do not adapt time or space sampling, but rather switch the positional degrees of freedom of particles on and off, while letting their momenta evolve. Therefore, inter-particles forces do not have to be updated at each time step, in contrast with traditional methods that spend a lot of time there. We present the initial formulation of ARPS that was introduced for molecular dynamics simulations, and explore its potential for Computer Graphics applications: We first adapt ARPS to particle-based fluid simulations and propose an efficient incremental algorithm to update forces and scalar fields. We then introduce a new implicit integration scheme enabling to use ARPS for cloth simulation as well. Our experiments show that this new, simple strategy for adaptive simulations can provide significant speedups more easily than traditional adaptive models.

Teaching

Main courses

Title Institute Hour Type Level Students Year
3D Computer Graphics Ensimag 18h TP Bac+4 30 2016
3D Computer Graphics Ensimag 18h TP Bac+4 30 2014
Synthèse d'Image Polytech Grenoble 12h TP Bac+4 30 2014
Visualisation Scientifique UJF, UFR IMAG 9h TP Bac+5 30 2014
Géométrie Numérique UJF, UFR IMAG 16.5h TP Bac+4 30 2014

Personal contributions

In 2015, I proposed to completely update the practicals for the course of 3D Graphics at Ensimag. With the help of Thomas Delame, I built a small game engine targeted for beginners in OpenGL 4 and allowing to getting familiar with modern GPU technologies. Aside from the engine, I wrote seven tutorials to introduce essential concepts of Computer Graphics: rendering, modeling and animation. A final project was proposed at the end of the course, students had to produce a kart racing game. They actually produced nice results.

Specific courses

I participated to the management of students during the time of special project at Ensimag. These projects allowed me to be involved in advanced scientific problems on different topics. The list of the project I was involved in is just below. Also, from 2013 to 2016 I was invited to be part of the jury of these projects.
Title Institute Hours Level Students Year
Génération d'un écosystème Ensimag 10h Bac+4 4 2016
Modélisation et animation des changements de forme d'une plaquette sanguine Ensimag 10h Bac+4 3 2016
Simulation d'un fluide en milieu poreux Ensimag 10h Bac+4 4 2016
Animation sonorisé de la déchirure du papier Ensimag 10h Bac+4 4 2015
Simulation d'un fluide à l'aide de particules SPH Ensimag 10h Bac+4 4 2013
Simulation des équations de Shallow-Water avec SPH Ensimag 10h Bac+4 4 2013