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 degen...

This paper describes an automatic and efficient approach to construct unstructured tetrahedral and hexahedral meshes for a composite domain made up of heterogeneous materials. The boundaries of these material regions form non-manifold surfaces. In earlier papers, we developed an octree-based isocontouring method to construct unstructured 3D meshes for a single-material (homogeneous) domain with...

Data capture technologies like airborne LIDAR produce extremely large models of digital terrain, which must be simplified to be useful. Garland and Heckbert’s quadric error metric in conjunction with edge contraction gives a greedy approach to simplify a mesh that can fit in memory; we adapt it to work with boundaries and labels (e.g., object ID, ground vs. building, or some discrimination betw...

Inspired by recent developments in contraction-based curve skeleton extraction, we formulate the skeletonization problem via mean curvature flow (MCF). While the classical application of MCF is surface fairing, we take advantage of its area-minimizing characteristic to drive the curvature flow towards the extreme so as to collapse the input mesh geometry and obtain a skeletal structure. By anal...

We consider the problem of simplifying a planar triangle mesh using edge contractions, under the restriction that the resulting vertices must be a subset of the input set. That is, contraction of an edge must be made onto one of its adjacent vertices, which results in removing the other adjacent vertex. We show that if the perimeter of the mesh consists of at most five vertices, then we can alw...

We introduce symmetry hierarchy of man-made objects, a high-level structural representation of a 3D model providing a symmetry-induced, hierarchical organization of the model’s constituent parts. Given an input mesh, we segment it into primitive parts and build an initial graph which encodes inter-part symmetries and connectivity relations, as well as self-symmetries in individual parts. The sy...

jachymski [ proc. amer. math. soc., 136 (2008), 1359-1373] gave modified version of a banach fixed point theorem on a metric space endowed with a graph. in the present paper, (g, φ)-graphic contractions have been de ned by using a comparison function and studied the existence of fixed points. also, hardy-rogers g-contraction have been introduced and some fixed point theorems have been proved. s...

we report the cases of two patients diagnosed with morgagni hernia who presented with nonspecific abdominal symptoms. both underwent laparo­scopic surgery that used a dual-sided mesh, polyvinylidene fluoride (pvdf; dynamesh ipom®). the procedures were successful and both patients were discharged with no complications. there was no recurrence in 18 months of follow up. herein is the report of th...

aims: it is very important to detect the coagulase-negative staphylococci, which produce the hospital infections. being one of the most expensive and time-consuming stages before the polymerase chain reaction (pcr), dna extraction is one of the primary stages of pcr. then, it should be noticed that the elimination of the stage might save time and costs. the aim of this study was to compare two ...

background: the aim of this study is to evaluate the long and short ten postoperative results after the notaras procedure as a surgical treatment of rectal prolapse in adults. methods: thirty-one patients suffering from rectal prolapse who were operated with notaras posterior mesh rectopexy in shohada-e-tajrish hospital between 1991- 2000 were followed up for results and complications and the r...