Les arbres VSG : une nouvelle approche multimodèles de la visualisation

Visualization takes an important place in CAD-CAM systems. It is often the best way to understand the results of a number of processes. The CPU times of realistic pictures including reflections, transparences, shadows and so on, are still very large, which forbids their use during interactive phases. To reduce these CPU times, we propose, in a multi-model approach, a method lying on a new visualization model, called VSG (visual solid geometry). This model has intrinsic properties that improve visualization algorithms and we have specially tried to adapt the ray-casting to it because of high quality images this method producesLa visualisation occupe une place importante dans les systèmes de CFAO (conception et fabrication assistée par ordinateur). C'est souvent le meilleur moyen d'appréhender les résultats des traitements réalisés par la machine. Le temps de calcul des images réalistes contenant réflexions, transparences, ombres portées, etc. sont encore aujourd'hui très important, ce qui interdit leur utilisation dans les phases interactives. Le problème aborde dans ce mémoire est de réduire ces temps de calcul en proposant, dans le cadre d'une approche multimodèles des systèmes de CFAO, un nouveau modèle de visualisation, appelé VSG (visual solid geometry), dont les propriétés constituent à elles seules une amélioration. Nous cherchons en particulier à utiliser au mieux ce modèle avec l'algorithme du lancer de rayons qui permet d'obtenir le réalisme souhait

A methodology for a function-to-shape translation tool in foundry

International audienceFunctional design aims at assisting the designer during all the design process, from specifications to manufacturing, even beyond that. One of the key stages of this process is the translation of functions into shapes. In this article, we first study a pragmatic method used to design moulds of foundry. Then, we introduce a theoretical method whose drawback is to generate a too huge solutions space of shapes to be industrially applied. From this comparison, we propose an intermediate approach, called mixed method. It consists in applying the theoretical method by integrating some expert knowledge of the foundry in order to obtain a reasonably wide solutions space automatically

A methodology for a function-to-shape translation tool in foundry

International audienceFunctional design aims at assisting the designer during all the design process, from specifications to manufacturing, even beyond that. One of the key stages of this process is the translation of functions into shapes. In this article, we first study a pragmatic method used to design moulds of foundry. Then, we introduce a theoretical method whose drawback is to generate a too huge solutions space of shapes to be industrially applied. From this comparison, we propose an intermediate approach, called mixed method. It consists in applying the theoretical method by integrating some expert knowledge of the foundry in order to obtain a reasonably wide solutions space automatically