Nicolas Castagné

A New Way to Model Physics-Based Topology Transformations: Splitting MAT

This work focuses modelling and simulation of physics-based topological discontinuities in deformable objects, as they appear in fracturing, tearing or cracking phenomena. It introduces a new methodology, called “Splitting MAT”, which integrates into masses-interactions modelling. This methodology enables modelling topological discontinuities not on an interaction element, but directly on a mass element. The principles of the Splitting MAT method are presented and then illustrated through various models featuring topological transformations due to large physics based deformations. The properties of the method are analyzed: optimization of the modelling process of topological transformations, and fully stable memory and computational costs.

Exploring the Role of Dynamic Audio-Haptic Coupling in Musical Gestures on Simulated Instruments

Recent developments at ACROE-ICA have yielded a first audio-haptic modeller-simulator for real time simulations of mass-interaction physical models. This paper discusses the conceptual and technological considerations for a haptic platform that supports dynamic coupling for audio-haptic interactions, in particular in the case of physical coupling with virtual musical instruments. We present work concerning system calibration and metrology, then demonstrate a model developed with this platform, exhibiting dynamic gesture-sound coupling. The quality of the haptic device’s dynamics along with the modularity of mass interaction physical modelling allow for subtle and highly precise interaction with simulated objects, enabling intricate musical gestures relying on high-bandwidth audio-haptic coupling.

A Topological-Geometrical Pipeline for 3D Cracking-like Phenomena

Animation of one-to-many phenomena (fractures, tears, breaks, cracks...) is challenging. This article builds over recent works that proposed a 3-stages modelling and simulation pipeline, made of a cascade of models: geometry-free physical model → explicit modelling of the evolving topology → geometrical model. On the Physics’ side, in the framework of masses-interactions network modelling, the article extends the recent Splitting-MAT method, where the physical splits occur onto the material points, toward 3 dimensional volume models. Downstream, it introduces a topo-geometrical pipeline adapted to this upstream split-on-the-masses property. Experiments, and analysis of the complexity of the topo-geometrical part, show that, while offering constructible and manageable means, separating Physical, Topological and Geometrical aspects in the 3stages pipeline enables a rich variety of one-to-many dynamics, with good efficiency.

Haptics Processing Unit Software Architecture for Transportable High Dynamics Force-Feedback Coupling

This article is a contribution to today’s stream of research studying the interests of employing a Haptics Coprocessing Unit (HPU) for force-feedback interaction, and possible core features and hardware/software architectures of such HPU. It introduces a force-feedback software framework, called CORDIS-In, powered by a DSP-based HPU. CORDIS-In’s design was driven so as to obtain a transportable platform, however able to provide very high dynamics force-feedback coupling. It provides time deterministic synchronous computing of any mass-interaction physics-based network, possibly at high simulation rates, high precision and programmability in adjusting the mechanical coupling of the user and the simulation through the device, and generic communication protocols with the host.

Sound synthesis and musical composition with the physical modeling formalism Cordis-Anima

The two historical starting points of Computer Music, in 1957, were digital sound synthesis, founded by Max Mathews (Bell Labs), and automatic composition, founded by Lejaren Hiller and Leonard Isaacson (University of Illinois). Digital sound synthesis and computer aided musical composition then developed and are today essential components of computer music. As said by Jean-Claude Risset, sound synthesis allowed to compose the sound itself. At the end of the 1970s, a new paradigm appeared, no more based on the synthesis of the sound signal, but on the simulation of the physical objects that produce the sound. The Cordis-anima language, created by Claude Cadoz and his colleagues Annie Luciani and Jean-Loup Florens at the ACROE lab, in Grenoble (France), is one of the most important representatives of this approach. We will present this language, which allows simulating the various components of a musical instrument, but also complex orchestras and dynamic objects with macro temporal behaviors. We will then...