A new 3D morphing algorithm for polyhedral objects with the same genus is presented in the paper. Our main contribution is an efficient and general algorithm for setting up the vertex correspondence between the polyhedra. The proposed algorithm first interactively partitions the two original polyhedra into the same number of polygonal patches, the patch correspondence is also established during partitioning. Each pair of corresponding patches is then parametrized and resampled by using the harmonic maps. A feature polyhedron is finally constructed for each original polyhedron, and the vertex correspondence between each original polyhedron and its feature polyhedron is automatically established following a cluster scheme. The shape transition between the original polyhedral models is accomplished by composing three successive transformations using their feature polyhedra as the bridges. Experimental results demonstrate that our algorithm is very robust, and can deal with very general cases (non-zero genus polyhedral cases).

This paper proposes a new preprocessing method for interactive rendering of complex polygonal virtual environments. The approach divides the space that observer can reach into many rectangular viewpoint regions. For each region, an outer rectangular volume(ORV) is established to surround it. By adaptively partitioning the boundary of the ORV together with the viewpoint region, all the rays that originate from the viewpoint region are divided into the beams whose potentially visible polygon number is less than a preset threshold. If a resultant beam is the smallest and intersects many potentially visible polygons, the beam is simplified as a fixed number of rays and the averaged color of the hit polygons is recorded. For other beams, their potentially visible sets (PVS) of polygons are stored respectively. During an interactive walkthrough, the visual information related to the current viewpoint is retrieved from the storage. The view volume clipping, visibility culling and detail simplification are efficiently supported by these stored data. The rendering time is independent of the scene complexity.

In this paper, we present a novel fairing algorithm for the removal of noise from uniform triangular meshes without shrinkage and serious distortion. The key feature of this algorithm is to keep all triangle centers invariant at each smoothing step by including some constraints in the energy minimization functional. The constrained functional is then minimized efficiently using an iterative method. Further, we apply this smoothing technique to a multiresolution representation to remove arbitrary levels of detail. A volume-preserving decimation algorithm is presented to generate the multiresolution representation. The experimental results demonstrate the combined algorithm's stability and efficiency.

A new non-linear view interpolation algorithm is presented in this paper. Unlike the linear interpolation scheme, our method can exactly simulate the perspective viewing transformation during walkthrough. To accelerate the view interpolation, the algorithm employs a binary subdivision scheme to optimize the decomposition of the source image so that the number of resultant blocks is greatly reduced. Holes in the intermediate image are filled by two steps, namely enlarging the transferred blocks at the sides adjacent to holes and retrieving the local image within holes from the destination images by multidirectional interpolation. Experimental results demonstrate that our algorithm is much more accurate and efficient than the traditional one. Copyright.

Polygonal models have been widely applied in the community of CAD and computer graphics. Since a polygonal surface usually has no intrinsic parameterization, it is very difficult to map textures onto it with low distortion. In this paper, we present an efficient texture mapping algorithm for polygonal models. For each region to be mapped, the algorithm first constructs a B-spline patch with similar shape to surround the model. The mapped region is then projected onto the constructed B-spline patch to achieve a parameterization. By interactively controlling the B-spline patch, the user can conveniently decorate the surface of the model to meet his requirements. Both local and global texture mapping are discussed. The experimental results demonstrate that the algorithm has a great of potential applications in computer animation and virtual reality systems.