摘要:

AbstractThis paper discusses techniques for the computation of global illumination in environments with a participating medium using a Monte Carlo simulation of the particle model of light. Efficient algorithms and data structures for tracking the particles inside the volume have been developed. The necessary equation for computing the illumination along any given direction has been derived for rendering a scene with a participating medium. A major issue in any Monte Carlo simulation is the uncertainty in the final simulation results. Various steps of the algorithm have been analysed to identify major sources of uncertainty. To reduce the uncertainty, suitable modifications to the simulation algorithm have been suggested using variance reduction methods offorced collision, absorption suppressionandparticle divergence.Some sample scenes showing the results of applying these methods are also included.

ISSN:1049-8907    

DOI:10.1002/vis.4340040303

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe dynamic constraints technique has been proposed for building geometrical models composed of rigid bodies, which are made to act naturally, according to Newtonian laws, by specifying constraints on their states. In computer animation, the dynamic constraints technique alleviates the work‐load of animators who formerly had to plan animated sequences in detail by intuition alone. Nevertheless, for some real‐world applications, it is desirable to have a mechanism that makes physically‐based elements move according to a given scenario by providing some control states. The control states can be represented by transient constraints that are to be met and then released immediately. In this paper, a technique called the sequential‐goal constraints technique is proposed to provide such a mechanism. With the sequential‐goal constraints technique, it is easy to specify transient constraints according to a given scenario and derive proper forces and torques to drive an element to meet each transient constraint exactly at a specified time so that the whole motion of the element is continuous and

ISSN:1049-8907    

DOI:10.1002/vis.4340040304

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractTo animate deformable objects through time and space, a new technique that will be referred to as DOGMA is proposed here. It is well suited to animation for both interactive design and real‐time visualization.The concept of animation primitives based on an extension to animation of the space deformation model is introduced. Animation primitives can be added to any geometrical modeller because they are independent of the underlying geometrical model of the animated objects. It encapsulates animation through space and time under a unique formalism. A local control of deformations both through space and time is easily specified. A direct manipulation of objects is provided. At any time, animated objects are continuously computed from their corresponding animation primitives. This dispenses with the necessity for major storage of the interpolation process. A fully interactive system offers an interactive environment which enables the user to animate deformable objects in real tim

ISSN:1049-8907    

DOI:10.1002/vis.4340040305

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:1049-8907    

DOI:10.1002/vis.4340040306

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:1049-8907    

DOI:10.1002/vis.4340040302

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY