Transitive mesh space of a progressive mesh (original) (raw)
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Truly selective refinement of progressive meshes
This paper presents a novel selective refinement scheme of progressive meshes. In previous schemes, topology information in the neighborhood of a collapsed edge is stored in the analysis phase. A vertex split or edge collapse transformation is possible in the synthesis phase only if the configuration of neighborhood vertices in the current mesh corresponds to the stored topology information. In contrast, the proposed scheme makes it possible to apply a vertex split or an edge collapse to any selected vertex or edge in the current mesh without a precondition. Our main observation is that the concept of a dual piece can be used to clearly enumerate and visualize the set of all possible selectively refined meshes for a given mesh. Our refinement scheme is truly selective in the sense that each vertex split or edge collapse can be performed without incurring additional vertex split and/or edge collapse transformations.
Selective refinement of progressive meshes using vertex hierarchies
Computers & Graphics, 2003
This paper presents a general method for selectively refining or coarsening progressive meshes. Our method works for arbitrary meshes, deals with non-manifolds, and allows the change of manifold and genus properties of the mesh. We introduce new definitions for edge contraction and expansion operations, which make solely use of the vertex hierarchy. These definitions in conjunction with their legal conditions lead to many provable properties of the refinement process. In addition, we propose a locally re-stripping method to dynamically generate the strips during selective refinements, which efficiently forms strips for meshes coarsening or refining process.
Progressive Meshes with Controlled Topology Modifications
Due to the rapid evolution of 3D acquisition and modeling methods highly complex and detailed models became ubiquitous. In order to be able to cope with the complexity, concentrated efforts were dedicated to the development of new mesh decimation methods in the recent years. In works of Garland and Heckbert [Garland and Heckbert 1997] and Popović and Hoppe [Popović and Hoppe 1997], the traditional edge contraction operator was generalized to vertex contraction, which allowed for topology modification during the decimation. The vertex contraction facilitates the joining of originally disconnected regions of the mesh by contracting vertices lying in different connected components of the model. While this operation provides considerable topological flexibility during the mesh simplification, in some cases joining of disconnected regions might be desirable only along the boundaries of the model. As a combination of two already available techniques, we present a mesh decimation technique allowing for increased control over topology changes induced by the decimation process. Our method proceeds in essence by applying two types of operators: the well known edge contraction and the vertex-edge contraction introduced recently by Borodin et al [Borodin et al. n. d.]. This facilitates efficient mesh simplification and gradual closing of gaps along the boundaries of the model. The process is controlled by a geometric error and since inverse operations may be implemented for both of the operators, it is conducted in a progressive manner.
Highly detailed geometric models are rapidly becoming commonplace in computer graphics. These models, often represented as complex triangle meshes, challenge rendering performance, transmission bandwidth, and storage capacities. This paper introduces the progressive mesh (PM) representation, a new scheme for storing and transmitting arbitrary triangle meshes. This efficient, loss-less, continuous-resolution representation addresses several practical problems in graphics: smooth geomorphing of level-of-detail approximations, progressive transmission, mesh compression, and selective refinement. In addition, we present a new mesh simplification procedure for constructing a PM representation from an arbitrary mesh. The goal of this optimization procedure is to preserve not just the geometry of the original mesh, but more importantly its overall appearance as defined by its discrete and scalar appearance attributes such as material identifiers, color values, normals, and texture coordinates. We demonstrate construction of the PM representation and its applications using several practical models.
Progressive Gap Closing for MeshRepairing
Advances in Modelling, Animation and Rendering, 2002
Modern 3D acquisition and modeling tools generate high-quality, detailed geometric models. However, in order to cope with the associated complexity, several mesh decimation methods have been developed in the recent years. On the other hand, a common problem of geometric modeling tools is the generation of consistent three-dimensional meshes. Most of these programs output meshes containing degenerate faces, T-vertices, narrow gaps and cracks. Applying well-established decimation methods to such meshes results in severe artifacts due to lack of consistent connectivity information. The industrial relevance of this problem is emphasized by the fact that as an output of most of the commercial CAD/CAM and other modeling tools, the user usually gets consistent meshes only for separate polygonal patches as opposed to the whole mesh. In this paper we propose a solution, which interprets the above issue as a mesh boundary decimation task. As suggested by Garland and Heckbert [4] and Popović and Hoppe [12], adding a vertex pair contraction operation enables to join unconnected regions of the mesh. In addition to this and the usual edge-collapse operation, we introduce a new vertex-edge collapse operation. This provides extra support for closing gaps and stitching together the boundaries of triangle patches lying in near proximity to each other. In our method, the decimation process is error controlled and conducted in a progressive manner in terms of the error. Therefore, the user is enabled to visually inspect and interactively influence the procedure.
Dependency-Free Parallel Progressive Meshes
Computer Graphics Forum, 2012
The constantly increasing complexity of polygonal models in interactive applications poses two major problems. First, the number of primitives that can be rendered at real-time frame rates is currently limited to a few million. Secondly, less than 45 million triangles-with vertices and normal-can be stored per gigabyte. Although the rendering time can be reduced using level-of-detail (LOD) algorithms, representing a model at different complexity levels, these often even increase memory consumption. Out-of-core algorithms solve this problem by transferring the data currently required for rendering from external devices. Compression techniques are commonly used because of the limited bandwidth. The main problem of compression and decompression algorithms is the only coarse-grained random access. A similar problem occurs in view-dependent LOD techniques. Because of the interdependency of split operations, the adaption rate is reduced leading to visible popping artefacts during fast movements. In this paper, we propose a novel algorithm for real-time view-dependent rendering of gigabyte-sized models. It is based on a neighbourhood dependency-free progressive mesh data structure. Using a per operation compression method, it is suitable for parallel random-access decompression and out-of-core memory management without storing decompressed data.
CPH: A Compact Representation for Hierarchical Meshes Generated by Primal Refinement
Computer Graphics Forum, 2015
We present CPH (Compact Primal Hierarchy): a compact representation of the hierarchical connectivity of surface and volume manifold meshes generated through primal subdivision refinements. CPH is consistently defined in several dimensions and supports multiple kinds of tessellations and refinements, whether regular or adaptive. The basic idea is to store only the finest mesh, encoded in a classical monoresolution structure that is enriched with a minimal set of labels. These labels allow traversal of any intermediate level of the mesh concurrently without having to extract it in an additional structure. Our structure allows attributes to be stored on the cells not only on the finest level, but also on any intermediate level. We study the trade-off between the memory cost of this compact representation and the time complexity of mesh traversals at any resolution level.