20 results
Search Results
Now showing 1 - 10 of 20
Item Inverse Kinematics and Kinetics for Virtual Humanoids(The Eurographics Association, 2007) Boulic, Ronan; Kulpa, Richard; Karol Myszkowski and Vlastimil HavranThe present tutorial deals with the use of inverse kinematics and kinetics for postural adaptations of virtual hu- manoids to different kind of constraints. It first proposes an overview of the problematic of this thematic and then of the existing techniques. Then it technically describes two key approaches: the prioritized inverse kinematics for accurate and realistic adaptation and a CCD-like algorithm based on groups for fast and realistic adaptation of hundreds of characters in real-time.Item An Informed Environment Dedicated to the Simulation of Virtual Humans in Urban Context(Blackwell Publishers Ltd and the Eurographics Association, 1999) Farenc, Nathalie; Boulic, Ronan; Thalmann, DanielIn this paper, we outline the creation of an Informed Environment, dedicated to urban life simulation.We propose methods and tools for creating and providing the information necessary for animating virtual humans in a city using an Informed Environment. The Informed Environment is based on a hierarchical decomposition of a urban scene into Environment Entities providing geometrical information as well as semantic notions, thus allowing a more realistic simulation of human behaviour. In this manner, virtual humans can integrate with a certain kind of urban knowledge.Item ACM/EG Symposium on Computer Animation 2004(The Eurographics Association and Blackwell Publishing Ltd., 2004) Boulic, Ronan; Pai, Dinesh K.; Badler, Norman; Desbrun, Mathieu; Reveret, LionelItem Sketch-Based Per-Frame Inverse Kinematics(The Eurographics Association, 2016) Mahmudi, Mentar; Harish, Pawan; Callennec, Benoît Le; Boulic, Ronan; Jan BenderWe present a method that uses a sketch-based interface in conjunction with a parallelized per-frame inverse kinematics (Parallel- PFIK) method for the purpose of motion editing. The artist creates and edits 3D constraints through an intuitive and easy to use 2D interface. These constraints are passed to Parallel-PFIK in order to solve for the joint angles of the character in a fast and efficient manner. Parallel-PFIK employs multicore processors and current generation GPUs extending parallel damped least squares inverse kinematics to multiple frames in order to solve the entire animation in real time. Our method allows users to create and edit 3D animations using an intuitive 2D sketch-based interface bringing 2D artist into 3D character animation.Item An Efficient and Flexible Perception Pipeline for Autonomous Agents(Blackwell Publishers Ltd and the Eurographics Association, 1999) Bordeux, Christophe; Boulic, Ronan; Thalmann, DanielAgents 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 we address concerns about computation redundancy and data propagation through multiple filtering modules.Item Partial Finger Involvement Reflects into Grasping Tasks Performance and Accuracy(The Eurographics Association, 2020) Boban, Loën; Delahaye, Mathias; Boulic, Ronan; Kulik, Alexander and Sra, Misha and Kim, Kangsoo and Seo, Byung-KukThis paper presents a user study comparing a grasping algorithm we adapted for the Valve Index controller to common grasping approaches using the HTC Vive Wand or the Oculus Quest's Computer Vision-based finger tracking. It involved 24 participants performing two widely known manipulation tasks for each device: "Pick and Place" and "Grab and Reorient". Our results place our Index Controller approach as a good trade-off between the other two approaches regarding completion time and accuracy.Item Combined Direct and Inverse Kinematic Control for Articulated Figure Motion Editing(Blackwell Science Ltd and the Eurographics Association, 1992) Boulic, Ronan; Thalmann, DanielA new approach for the animation of articulated figures is presented. We 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 inserted into the secondary task of an inverse kinematic control scheme. This approach profits from the use of half-space Cartesian main tasks in conjunction with a parallel control of the articulated figure called the coach-trainee metaphor. In addition, a transition function is introduced so as to guarantee the continuity of the control. The resulting combined kinematic control scheme leads to a new methodology of joint-motion editing which is demonstrated through the improvement of a functional model of human walking.Item Interactive Motion Deformation with Prioritized Constraints(The Eurographics Association, 2004) Callennec, Benoît Le; Boulic, Ronan; R. Boulic and D. K. PaiIn this paper, we present an interactive motion deformation method to modify animations so that they satisfy a set of prioritized constraints. Our approach successfully handles the problem of retargetting, adjusting a motion, as well as adding significant changes to preexisting animations. We introduce the concept of prioritized constraints to avoid tweaking issues for competing constraints. Each frame is individually and smoothly adjusted to enforce a set of prioritized constraints. The iterative construction of the solution channels the convergence through intermediate solutions, enforcing the highest prioritized constraints first. In addition, we propose a new, simple formulation to control the position of the center of mass so that the resulting motions are physically plausible. Finally, we demonstrate that our method can address a wide range of motion editing problems.Item A Generic Method for Geometric Contraints Detection(Eurographics Association, 2004) Salvati, Marc; Lecallennec, Benoît; Boulic, Ronan; M. Alexa and E. GalinIn this paper, we present a generic method to automatically detect geometric constraints on motion capture animations. At each frame, elementary geometric constraints are computed with respect to a reference which can either be the world coordinate system or any moving object in the scene. We then use constraint-related concepts of union and intersection to merge the elementary constraints together and/or to generate new ones. Finally, our algorithm provides an exhaustive list of geometric constraints with an accurate evaluation of their duration. The detected constraints can characterize virtual human motion (e.g. footprints) as well as interactions with moving objects of the scene (e.g. a hand touching a ball). While our approach also detects sliding geometric constraints, we focus our discussion on detecting positional geometric constraints.Item Egocentric Normalization of Kinematic Path(The Eurographics Association, 2015) Molla, Eray; Boulic, Ronan; B. Solenthaler and E. PuppoWe focus on retargetting the class of movements involving self-interactions onto characters with different size and proportion. Such postures may produce self-collisions and/or alter the intended semantics. We introduce a technique to normalize the spatial relationship vectors between the body parts of the source character. This allows for morphological adaptation of these vectors onto the target characters, hence preserving the semantics in postures with and without body-contact.