3 results
Search Results
Now showing 1 - 3 of 3
Item Efficient Fitting and Rendering of Large Scattered Data Sets Using Subdivision Surfaces(Blackwell Publishers, Inc and the Eurographics Association, 2002) Scheib, Vincent; Haber, Jorg; Lin, Ming C.; Seidel, Hans-PeterWe present a method to efficiently construct and render a smooth surface for approximation of large functional scattered data. Using a subdivision surface framework and techniques from terrain rendering, the resulting surface can be explored from any viewpoint while maintaining high surface fairness and interactive frame rates. We show the approximation error to be sufficiently small for several large data sets. Our system allows for adaptive simplification and provides continuous levels of detail, taking into account the local variation and distribution of the data.Categories and Subject Descriptors (according to ACM CCS): G.1.2 [Approximation]: Approximation of surfaces, Least squares approximation, Piecewise polynomial approximation; I.3.3 [Picture/Image Generation]: Display algorithms, Viewing algorithms; I.3.5 [Computational Geometry and Object Modeling]: Surface representation.Item Hardware-Based Volumetric Knit-Wear(Blackwell Publishers, Inc and the Eurographics Association, 2002) Daubert, Katja; Seidel, Hans-PeterWe present a hardware-based, volumetric approach for rendering knit wear at very interactive rates. A single stitch is represented by a volumetric texture with each voxel storing the main direction of the strands of yarn inside it. We render the knit wear in layers using an approximation of the Banks model. Our hardware implementation allows specular and diffuse material properties to change from one voxel to the next. This enables us to represent yarn made up of different components or render garments with complicated color patterns. Furthermore, our approach can handle self-shadowing of the stitches, and can easily be adapted to also include view-independent scattering. The resulting shader lends itself naturally to mip-mapping, and requires no reordering of the base geometry, making it versatile and easy to use.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Computer Graphics]: Hardware Applications Volumetric TexturesItem Grid Based Final Gather for Radiosity on Complex Clustered Scenes(Blackwell Publishers, Inc and the Eurographics Association, 2002) Scheel, Annette; Stamminger, Marc; Seidel, Hans-PeterRadiosity methods handle large scenes and complex objects using clustering techniques. To reconstruct a high quality image, usually a second very time consuming final gather pass is applied which exactly recomputes the last light transport before reaching the eye. We propose a new final gather technique which is especially suited for scenes with fine polygonal geometry. In such scenes, substantial parts of the incident illumination vary only smoothly across the surfaces and can be reconstructed on a much coarser structure. We therefore propose a final gather reconstruction based on an object-independent 3D grid. The illumination of each sender is investigated separately: If it varies smoothly across a grid cell, it is interpolated between the vertices of the grid cell, or recomputed exactly, otherwise. We further reduce the number of required samples using view-dependent optimizations. So complex objects with a very detailed structure-plants are good example here-exhibit strong masking effects, which can be exploited by our method. Finally, the estimation of penumbra screen sizes can be used to further reduce costly visibility reevaluations.Categories and Subject Descriptors (according to ACM CCS): I.3.3 [Copmuter Graphics]: Picture/Image generation I.3.7 [Copmuter Graphics]: Three-Dimensional Graphics and Realism