Publications by Ronan Boulic | EPFL Graph Search

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Most of today's virtual environments are populated with some kind of autonomous life-like agents. Such agents follow a preprogrammed sequence of behaviours that excludes the user as a participating entity in the virtual society. In order to make inhabited virtual reality an attractive place for information exchange and social interaction, we need to equip the autonomous agents with some perception and interpretation skills. We present one skill: human action recognition. By opposition to human-computer inte

Optical motion capture provides an impressive ability to replicate gestures. However, even with a highly professional system there are many instances where crucial markers are occluded or when the algorithm confuses the trajectory of one marker with that of another. This requires much editing work on the user's part before the complete animation is ready for use. Here, the authors present an approach to increasing the robustness of a motion capture system by using an anatomical human model. It includes a re

A new approach for the animation of articulated figures is presented. The authors propose a system of articulated motion design which offers a full combination of both direct and inverse kinematic control of the joint parameters. Such an approach allows an animator to specify interactively goal-directed changes to existing sampled joint motions, resulting in a more general and expressive class of possible joint motions. The fundamental idea is to consider any desired-joint space motion as a reference model

Presents a new architecture for simulating virtual humans in complex urban environments. The approach is based on the integration of six modules. Four key modules are used in order to manage environmental data, simulate human crowds, control interactions between virtual humans and objects, and generate tasks based on a rule-based behavioral model. The communication between these modules is made through a client/server system. Finally, all low-level virtual human actions are delegated to a single motion and

This project investigates the impact of a virtual zero gravity experience on the human gravity model. In the planned experiment, subjects are immersed with HMD and full body motion capture in a virtual world exhibiting either normal gravity or the apparent ...

The current study sought to objectively evaluate cybersickness by utilizing Electrogastrogram (EGG) physiological data in relation to three different navigation axes: Translational movement along the longitudinal and lateral axes, and rotation along the ve ...

We present a posture design paradigm for the positioning of complex characters. It is illustrated here on human figures. We exploit the inverse kinetics technique which allows the center of mass position control for postures with either single or multiple supports. For the multiple support case, we introduce a compatible flow model of the supporting influence. With this approach, we are able to handle continuous modification of the support distribution. By construction, inverse kinetics presents the same co

The present paper describes the integration of a multi-finger haptic device with deformable objects in an interactive environment. Repulsive forces are synthesized and rendered independently for each finger of a user wearing a Cybergrasp force-feedback glove. Deformation and contact models are based on mass-spring systems, and the issue of the user independence is dealt with through a geometric calibration phase. Motivated by the knowledge that human hand plays a very important role in the somatosensory sys

Presents an integration framework for heterogeneous motion generators. The objective is to outline issues that are currently easily solved in the professional post-processing systems used in film and game production but which cannot be transposed “as-is” to real-time systems with autonomous agents. We summarise our approach for articulated agent modelling and their animation by combining heterogeneous motion generators, such as real-time motion capturing, key-framing, inverse kinematics and proc

A common problem in virtual character computer animation concerns the preservation of the basic foot-floor constraint (or footplant), consisting in detecting it before enforcing it. This paper describes a system capable of generating motion while continuou ...

Non-verbal communication (NVC) makes up about two-thirds of all communication between two people or between one speaker and a group of listeners. However, this fundamental aspect of communicating is mostly omitted in 3D social forums or virtual world orien ...

Representing motions as linear sums of principal components has become a widely accepted animation technique. While powerful, the simplest version of this approach is not particularly well suited to modeling the specific style of an individual whose motion had not yet been recorded when building the database: it would take an expert to adjust the PCA weights to obtain a motion style that is indistinguishable from his. Consequently, when realism is required, the current practice is to perform a full motion c

Agents in virtual environments require a combination of perception and action to behave in an autonomous way. We extend a software architecture for the management of actions blending, called AGENTlib, with a perception mechanism. The perception system provides a uniform interface to various techniques in the field of virtual perception, including synthetic vision, database access and perception persistency. We describe the framework we designed to efficiently filter valuable information from the scene and w

This paper proposes a novel method to control virtual characters in dynamic environments. A virtual character is animated by a locomotion and jumping engine, enabling production of continuous parameterized motions. At any time during runtime, flat obstacle ...

An efficient inverse kinematics solver is a key element in applications targeting the on-line or off-line postural control of complex articulated figures. In the present paper we progressively describe the strategic components of a very general and robust inverse kinematics architecture. We then present an efficient recursive algorithm enforcing an arbitrary number of strict priorities to arbitrate the fulfillment of conflicting constraints. Due to its local nature, the moderate cost of the solution allows

A multi-level model of human actions involving full body motion is proposed. Actions are considered as the combination of action primitives at different levels: motions of the center of mass, end effectors, and final postures of the virtual skeleton. The model is especially designed for fast action recognition from the input of the human motion at the joint level

In this paper, we present an analytic-iterative Inverse Kinematics (IK) method, called Sequential lK (SIK), that reconstructs 3D human full-body movements in real time. The input data for the reconstruction is the least possible (i.e., the positions of wri ...

This paper addresses evaluation and visualization of stress and strain on soft biological tissues in contact given three-dimensional models of reconstructed organs from magnetic resonance images (MRI), we use an anatomy-based kinematical model combined with a soft tissues model to represent their shape and behavior. Then, we compute resulting distribution of stress and strain on deforming surface when motion is simulated. The computed stress and strain are then effectively visualized using an interactive an

This paper presents the results of a study performed in order to evaluate whether a navigation technique, based on scaling the user’s avatar, impacts the user’s ability to correctly assess the size of virtual objects in a virtual environment. This study wa ...

This paper introduces the Least Increase aversion (LIA) protocol to investigate the relative impact of factors that may trigger cybersickness. The protocol is inspired by the Subjective Matching methodology (SMT) from which it borrows the incremental const ...

Ronan Boulic

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Conferring human action recognition skills to life-like agents

Using skeleton-based tracking to increase the reliability of optical motion capture

Combined direct and inverse kinematic control for articulated figure motion editing

A paradigm for controlling virtual humans in urban environment simulations

Virtual Zero Gravity Impact on Internal Gravity Model

EGG Objective characterization of cybersickness symptoms towards navigation axis

Complex character positioning based on a compatible flow model of multiple supports

Multi-finger haptic rendering of deformable objects

Versatile tuning of humanoid agent activity

Robust on-line adaptive footplant detection and enforcement for locomotion

An Event-Based Architecture to Manage Virtual Human Non-Verbal Communication in 3D Chatting Environment

Style-based Motion Synthesis

An efficient and flexible perception pipeline for autonomous agents

Dynamic Obstacle Clearing for Real-time Character Animation

An inverse kinematics architecture enforcing an arbitrary number of strict priority levels

Multi-level modeling and recognition of human actions involving full body motion

Full-body performance animation with Sequential Inverse Kinematics

Evaluation and visualization of stress and strain on soft biological tissues in contact

Does scaling player size skew one’s ability to correctly evaluate object sizes in a virtual environment?

The Least Increasing Aversion (LIA) Protocol: Illustration on Identifying Individual Susceptibility to Cybersickness Triggers