Radiosity

2. Abstract Automatic 3D acquisition devices (often called 3D scanners) allow to build highly accurate models of real 3D objects in a cost-and time-effective manner. We have experimented this technology in a particular application context: the acquisition of Cultural Heritage artefacts. Specific needs of this domain are: medium-high accuracy, easy of use, affordable cost of the scanning device, self-registered acquisition of shape and color data, and finally operational safety for both the operator and the scanned artefacts. According to ...

Radiosity is the most established technique for simulating high exchange between surfaces considered as perfect diffusers. This paper presents a new topological structure for use in the context of hierarchical radiosity combined with discontinuity meshing. This is mostly useful for a new strategy adopted for subdividing the elements of a scene consisted of convex polygons.The subdivision is done in a local optimization manner keeping the aspect ratios of the produced polygons low. The generated meshes give high visual accuracy.

We advocate the use of point sets to represent shapes. We provide a definition of a smooth manifold surface from a set of points close to the original surface. The definition is based on local maps from differential geometry, which are approximated by the method of moving least squares (MLS). The computation of points on the surface is local, which results in an out-of-core technique that can handle any point set. We show that the approximation error is bounded and present tools to increase or decrease the density of the points, thus allowing an adjustment of the spacing among the points to control the error. To display the point set surface, we introduce a novel point rendering technique. The idea is to evaluate the local maps according to the image resolution. This results in high quality shading effects and smooth silhouettes at interactive frame rates.

This panel and audience will discuss the use of our experience and knowledge of data visualization methods, software, and hardware in presenting the rather abstract information contained in data bases, digital libraries, and other massive collections of data and information. The panelists and audience will examine and debate how to create effective information visualizations and how to use them effectively

The convergence of iterative methods used to solve the radiosity system of linear equations depends on the distribution of the eigenvalues of the radiosity coefficient matrix. In this paper we prove that all eigenvalues of the radiosity coefficient matrix are real and positive. This fact may allow us to obtain fast radiosity solutions using the knowledge about the spectrum of the matrix. Moreover, the physical meaning of the eigenvectors in global illumination applications is an open problem in graphics. In order to contribute to the clarification of this question, we present some experiments based on the theory of matrices, in which we show interesting features of using eigenvectors as solution vectors in graphics settings. CR Subject Classification: I.3.7 [Computer Graphics]: Three Dimensional Graphics and Realism. Additional