3D INTERACTIVE OBJECTS LAYOUT USING VIRTUAL REALITY TECHNIQUES AND CONSTRAINT PROGRAMMING Marouene Kefi, Paul Richard Laboratoire d’Ing´ enierie des Syst` emes Automatis´ es (LISA), Universit´ e d’Angers, 62 Avenue ND du Lac, Angers, France Vincent Barichard Laboratoire d’Etudes et de Recherche en Informatique d’Angers (LERIA) Universit´ e d’Angers, 2 Bd Lavoisier, Angers, France Keywords: Virtual environment, 3D Interaction, Decision-making, 3D Objects layout, Constraint programming. Abstract: Virtual Reality (VR) is a promising tool for effectively visualizing and interacting with objects and 3D envi- ronments. However, Virtual Environments (VEs) should provide some assistance to help the users in complex solving tasks. We aim to combine VR and Constraint Programming (CP) techniques in order to assist the users in realizing 3D objects layout in restricted spaces. The proposed approaches are based on a tight com- munication between a 3D rendering module and a highly efficient constraint solver. Layout modification are translated in incoming queries to the solver which generates the solutions that satisfy predefined constraints. In order to achieve users’ immersion in the VE and intuitive manipulation of the objects, a human-scale VE platform with haptic feedback is used. In this paper, we focus on the system architecture and we describe the implementation of simple constraints. Finally, some results based on geometric constraints are presented. 1 INTRODUCTION A spatial problem may be defined as a placement problem for which a positioning of components inside a container is seeked. The development of methods for automatic solving of such problems is challeng- ing while the systems become more complex. This is mainly explained by the difficulty related to the mod- eling and the formalization of these problems. Virtual Reality (VR) aims to immerse users in syn- thetic worlds in which they will experience multi- modal interactions with virtual objects (Bowman, 1999). VR is therefore a promising tool for effec- tively visualizing and interacting with 3D environ- ments (Drieux et al., 2005). However, in order to be really effective, virtual environments (VEs) should provide some assistance to help the users in complex solving tasks. We apropose to combine VR and Constraint Pro- gramming (CP) techniques in order to assist the users in 3D objects layout in restricted spaces. The context of this work is the design and the 3D layout of mili- tary vehicles or shelters. The proposed approaches in- volve a tight communication between a 3D rendering module and a highly efficient constraint solver. Lay- out modification are translated in incoming queries to the solver which generates the solutions that satisfy predefined constraints. A constraint expresses a prop- erty or a condition that must be satisfied. It can be defined as a relation-ship between one or more vari- ables. The notion of constraint is naturally present in several areas such as resources allocation, planning and industrial production. In the next section, we survey the previous work. Then, we present our system including a human-scale VR platform. We focus on the interaction model and the communication process between the 3D environ- ment and the solver. In section four, we describe in- teractive approaches based on CP techniques. In sec- tion five, we present the results associated with some basic geometric constraints. Then we examine the time required by the solver to compute the existing solutions of an under-constrained problem (two con- straints only). The paper ends by a conclusion that provides some tracks for future work. 308 Kefi M., Richard P. and Barichard V.. 3D INTERACTIVE OBJECTS LAYOUT USING VIRTUAL REALITY TECHNIQUES AND CONSTRAINT PROGRAMMING. DOI: 10.5220/0003377303080313 In Proceedings of the International Conference on Computer Graphics Theory and Applications (GRAPP-2011), pages 308-313 ISBN: 978-989-8425-45-4 Copyright c  2011 SCITEPRESS (Science and Technology Publications, Lda.)