Browsing by Author "Wyvill, B."
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- ItemOpen AccessInteractive Implicit Modeling With Hierarchical Spatial Caching(2005-03-08) Schmidt, R.; Wyvill, B.; Galin, E.Complex implicit CSG models can be represented hierarchically as a tree of nodes (the BlobTree). However, current methods cannot be used to visualize changes made to these models at interactive rates due to the large number of potential field evaluations required. A hierarchical spatial caching technique is presented which accelerates evaluations of the potential function. This method introduces the concept of a caching node inserted into the implicit model tree. Caching nodes store exact potential field values at the nodes of a voxel grid and rely on tri-linear and tri-quadratic reconstruction filters to locally approximate the potential field of a sub-tree. A lazy evaluation scheme is used to avoid expensive pre-computation. Polygonization timings with and without caching are compared for a complex model undergoing manipulation in an interactive modeling tool. An order-of-magnitude improvement in visualization time is achieved for complex implicit models containing thousands of primitives.
- ItemOpen AccessJADE status report: a local computing network for research in distributed programming environments(1986-01-01) Unger, Brian W; Birtwistle, G.; Cleary, J.; Hill, D.; Keenan, T.; Rokne, J.; Kendall, J.; Vollmerhaus, W.; Witten, I.; Wyvill, B.No abstract
- ItemOpen AccessSHRINKWRAP: AN ADAPTIVE ALGORITHM FOR POLYGONIZING AN IMPLICIT SURFACE(1993-03-01) van Overveld, C.W.A.M.; Wyvill, B.An algorithm is presented which generates a triangular mesh to approximate an equi-potential surface. The algorithm is adaptive in the sense that the lengths of the sides of the triangles in the mesh vary with the local curvature of the underlying surface. A quantitative analysis of the accuracy of the algorithm is given along with an empirical comparison with earlier algorithms.
- ItemOpen AccessSUBDIVISION SURFACES FOR FAST APPROXIMATE IMPLICIT POLYGONIZATION(2000-12-05) Wyvill, B.; Jepp, P.; van Overveld, K.; Wyvill, G.We propose a fast method of generating an approximate polygonal mesh from an implicit surface. Current workstations are still not capable of producing polygon meshes fast enough for the interactive modeling of complex implicit models. We propose a hybrid method that combines current implicit polygonization techniques with the faster sub-division surface technique applied as a post-process to smooth the implicit mesh. In an interactive environment the smooth mesh points can be migrated to the implicit surface, in idle moments when the user is not interacting with the model. The technique can be further enhanced by providing tools for the user to indicate areas of interest that can be preferentially smoothed.