Triangle Mesh Model Research Articles

Tangential Distance Fields for Mesh Silhouette Problems

Aabstract We consider a tangent-space representation of surfaces that maps each point on a surface to the tangent plane of the surface at that point. Such representations are known to facilitate the solution of several visibility problems, in particular, those involving silhouette analysis. In this paper, we introduce a novel class of distance fields for a given surface defined by its tangent planes. At each point in space, we assign a scalar value which is a weighted sum of distances to these tangent planes. We call the resulting scalar field a ‘tangential distance field’ (TDF). When applied to triangle mesh models, the tangent planes become supporting planes of the mesh triangles. The weighting scheme used to construct a TDF for a given mesh and the way the TDF is utilized can be closely tailored to a specific application. At the same time, the TDFs are continuous, lending themselves to standard optimization techniques such as greedy local search, thus leading to efficient algorithms. In this paper, we use four applications to illustrate the benefit of using TDFs: multi-origin silhouette extraction in Hough space, silhouette-based view point selection, camera path planning and light source placement.

A Client–Server Based View-Dependent Multiresolution Mesh Hierarchy

We propose a directed acyclic graph (DAG) hierarchy for view-dependent multiresolution mesh for client–server based online browsing of triangle mesh models. The multiresolution hierarchy and the selective mesh for rendering are two relatively independent units, residing on the server and the client respectively. The multiresolution hierarchy, which is a DAG of vertex-split operations, encodes all the dependent relationships between the vertex-splits, so that no extra legality checks on the surrounding neighborhood are required before a refinement or simplification operation. The DAG built by our algorithm has only a small number of redundant edges. This property can reduce run-time memory cost and time cost. We also present a method to incrementally traverse the DAG as the view parameters change. The incremental traversal exploits the frame-to-frame coherence and can produce consistent meshes. In addition, triangle budget of the client can be complied with by applying pairs of refinement and simplification operations to the selective mesh. The efficiency of our framework is demonstrated through a series of experiments.

Computer aided design and computer aided manufacture of sacrificial pattern of removable partial denture framework

To introduce a method applied in computer aided design and computer aided manufacture (CAD-CAM) of removable partial denture framework for rehabilitating edentulous arch of Kennedy Class II and found a basis for this project. Point cloud data of dental stone model was obtained by laser scanning. The following processes were made: drawing framework outline on the reconstructed triangle mesh model, picking up and processing its inner side data as the data of tissue surface, shelling it for 3-D model of framework, and transferring the data to rapid prototyping equipment for manufacture. 3-D model of the removable partial denture framework was preliminarily accomplished. The resin framework used as a sacrificial pattern was manufactured with the rapid prototyping equipment. The fit between resin framework and plaster model was good. This method, as an integrated procedure including data acquisition, 3-D computer modeling and fabrication by rapid prototyping, is feasible to implement CAD-CAM of removable partial denture framework.