4 research outputs found
Scripting interactive physically-based motions with relative paths and synchronization
This paper presents a novel approach for facilitating the use of physically based models by animators. The idea is to let the user guide motion at a high level of control by giving approximate desired trajectories and synchronization constraints between the objects over time, while a simulation module computes the final motion, dealing with collision detection and response, and enhancing realism. The objects, which are either isolated or components of an articulated structure, are guided through the specification of key-position and orientations, defined in a referential that can be fixed or relative to another object. The animation sequence is scripted by specifying a graph of synchronization constraints between objects over time. During the animation, objects automatically regulate their speed in order to meet these constraints. Résumé Cet article présente une nouvelle approche pour faciliter l’utilisation de modèles physiques par les graphistes. L’idée est de laisser l’utilisateur guider l’animation à un haut niveau de contrôle en donnant une approximation des trajectoires désirées et des contraintes de synchronisation temporelles entre les objets. Un module de simulation calcule ensuite le mouvement final, gérant les détections et réponses aux collisions, tout en améliorant le réalisme. Les objets, isolés ou composants d’une structure articulée, sont guidés par la spécification de positions et orientations-clés, définies dans un repère fixe ou relatif à un autre objet. La séquence d’animation est définie par la spécification d’un graphe de contraintes de synchronisation entre les objets au cours du temps. Pendant l’animation, les objets régulent automatiquement leur vitesse pour satisfaire ces contraintes
The application of three-dimensional mass-spring structures in the real-time simulation of sheet materials for computer generated imagery
Despite the resources devoted to computer graphics technology over the last 40 years,
there is still a need to increase the realism with which flexible materials are simulated.
However, to date reported methods are restricted in their application by their use of
two-dimensional structures and implicit integration methods that lend themselves to
modelling cloth-like sheets but not stiffer, thicker materials in which bending moments
play a significant role.
This thesis presents a real-time, computationally efficient environment for simulations
of sheet materials. The approach described differs from other techniques principally
through its novel use of multilayer sheet structures. In addition to more accurately
modelling bending moment effects, it also allows the effects of increased temperature
within the environment to be simulated. Limitations of this approach include the
increased difficulties of calibrating a realistic and stable simulation compared to
implicit based methods.
A series of experiments are conducted to establish the effectiveness of the technique,
evaluating the suitability of different integration methods, sheet structures, and
simulation parameters, before conducting a Human Computer Interaction (HCI) based
evaluation to establish the effectiveness with which the technique can produce credible
simulations. These results are also compared against a system that utilises an
established method for sheet simulation and a hybrid solution that combines the use of
3D (i.e. multilayer) lattice structures with the recognised sheet simulation approach.
The results suggest that the use of a three-dimensional structure does provide a level of
enhanced realism when simulating stiff laminar materials although the best overall
results were achieved through the use of the hybrid model