Cluster-based three-dimensional non-uniform mesh simplification algorithm

Author(s):  
Chao Yang ◽  
Xiaoqing Yu ◽  
Xuannan Ye
Author(s):  
Paolo Tartarini ◽  
Mauro A. Corticelli ◽  
Paolo E. Santangelo

Dropwise cooling represents a major subject of interest for both academic and industrial researches. The present work is focused on investigating the thermal transient occurring as two water droplets are gently released (We < 30) onto a heated solid surface. This latter has been kept at initial temperature lower than 373.15 K to analyze the single-phase-evaporation regime. To the purpose, both an experimental and a numerical approach have conveniently been employed. Infrared thermography has been used to evaluate the temperature trend at the solid-liquid interface: an experimental facility has been built to carry out measurements from below, thus realizing a fully non-intrusive approach. A transparent-crystal disk has been inserted to serve as the solid substrate; its upper surface has been painted by a black coating, thus providing a black-body surface as the solid-liquid interface. The infrared thermocamera has been placed below and perpendicular to that surface; temperature has been thereby measured, being emissivity a known parameter. A numerical code has been developed to predict the involved physical phenomena: temperature trend, evaporation time and evaporated flux result from discretizing the three-dimensional energy-diffusion equation by the finite-volume method. Moreover, the model is based on structured non-uniform mesh to adapt to the occurring temperature gradients. Very good agreement is shown between experimental and numerical outcomes in terms of thermal transient and recovery.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yongzhi Wang ◽  
Jianwen Zheng ◽  
Hui Wang

To avoid excessive details, thus omitting less important content, of three-dimensional (3D) geometric models, this study proposes a fast mesh simplification method based on an energy-operator for 3D geometric models with salient feature-preserving efficiency. The energy-operator can evaluate the smoothness and complexity of the regional mesh in 3D models. Accordingly, it can be directly used to simultaneously reduce the candidate triangle and its three neighboring triangles. The proposed method can dramatically collapse the excessive details in relatively smooth areas and preserve more important salient features during the simplification process. It can also maintain a trade-off between time efficiency and salient feature-preserving accuracy. The effectiveness and efficiency of the new method are demonstrated by comparing it with OpenMesh, which is considered the most popular mesh operation software and is capable of achieving accurate mesh simplification models. The new mesh simplification method based on the energy-operator can provide accurate and concise models for interactive 3D rendering, calculating, simulating, and analyzing.


Author(s):  
Daniel Jie Yuan Chin ◽  
Ahmad Sufril Azlan Mohamed ◽  
Khairul Anuar Shariff ◽  
Mohd Nadhir Ab Wahab ◽  
Kunio Ishikawa

Three-dimensional reconstruction plays an important role in assisting doctors and surgeons in diagnosing bone defects’ healing progress. Common three-dimensional reconstruction methods include surface and volume rendering. As the focus is on the shape of the bone, volume rendering is omitted. Many improvements have been made on surface rendering methods like Marching Cubes and Marching Tetrahedra, but not many on working towards real-time or near real-time surface rendering for large medical images, and studying the effects of different parameter settings for the improvements. Hence, in this study, an attempt towards near real-time surface rendering for large medical images is made. Different parameter values are experimented on to study their effect on reconstruction accuracy, reconstruction and rendering time, and the number of vertices and faces. The proposed improvement involving three-dimensional data smoothing with convolution kernel Gaussian size 0.5 and mesh simplification reduction factor of 0.1, is the best parameter value combination for achieving a good balance between high reconstruction accuracy, low total execution time, and a low number of vertices and faces. It has successfully increased the reconstruction accuracy by 0.0235%, decreased the total execution time by 69.81%, and decreased the number of vertices and faces by 86.57% and 86.61% respectively.


2019 ◽  
Vol 15 (1) ◽  
pp. 155014771882245
Author(s):  
Hongjie Yang ◽  
Fan Zhou ◽  
Ge Lin ◽  
Mouguang Lin ◽  
Shujin Lin

The three-dimensional animated model is widely used in scientific visualization, entertainment, and virtual applications, especially in visual sensor networks. The main purpose of simplification is to capture the shape sequence of an object with very few elements while preserving the overall shape. As three-dimensional animated mesh is time-varying in all frames, the trade-off between the temporal coherence and geometric distortion must be considered to develop simplification algorithm. In this article, a novel three-dimensional animated mesh simplification algorithm based on motion features is presented. Here, motion features are the connection areas of the relative movement consisted of vertices and edges. Motion feature extraction is to find a subgraph that has movement property. Dihedral angle of the edge through all frames is used to determine whether an edge is connected or not to the movement parts. Then, a rotation connected graph is defined to extract motion features. Traveling this graph, all motion features can be extracted. Based on the motion features, animated quadric error metric is created and quadric error matrix is built through all frames. Compared with the other methods, the important advantages of this method are high-efficiency simplification process and smoother simplification effects. It is suitable to be used in real-time applications. Experiment results show that the 3D animated mesh simplification effects by our method are satisfactory.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhongxing Zhang ◽  
Yan Zhang ◽  
Xiaohui Wang ◽  
Xiaoli Han ◽  
Xin Zhang ◽  
...  

This paper aimed to study the clinical characteristics of patients with pulmonary embolism (PE) with syncope (PE + S) based on the three-dimensional (3D) reconstruction algorithm in computed tomography (CT) pulmonary angiography (CTPA). In this study, 857 patients with acute PE (APE) who were treated in hospital were selected as the research objects and divided into syncope group (group S) and nonsyncope group (group NS). The 3D reconstruction marching cubes (3DR-MC) algorithm was compared with the traditional MC (T-MC) algorithm and the mesh simplification MC (MMS-MC) algorithm, and the results proved that the running time of the 3DR-MC algorithm on the platform was shorter than that of the other two algorithms. The incidence of syncope in group S in women was higher than that in group NS (51.7% vs. 38.2%). The incidence of syncope classified as high risk in group S was higher than that in group NS, and the mortality rate of pulmonary embolism patients with syncope was higher, and the difference was statistically significant (χ2 = 113.332, P < 0.05 ). The incidence of syncope in group S was higher than that in group NS (χ2 = 4.074, P < 0.05 ). In short, hypertension was an independent risk factor for syncope. PE + S patients could be diagnosed and treated as early as possible based on the clinical characteristics, so as to reduce the adverse consequences of misdiagnosis.


2010 ◽  
Vol 108-111 ◽  
pp. 586-591 ◽  
Author(s):  
Hai Bo Sun ◽  
Xiong Duan ◽  
Xin Gang Yao ◽  
Chao Tan

An improved progressive mesh simplification algorithm for 3D real-time level of detail rendering of shearer based on half-collapse was proposed, which has been successfully applied in the rendering of shearer and produced a good result. Virtools with its secondary development technology SDK (Software Development Kit) was applied to establishing a 3DVR(Three Dimensional Virtual Reality) digital information platform for shearer based on real-time archiving of important working parameters. By using the real-time data provided by the remote control and monitoring system for shearer, the virtual 3D model was driven to reappearance the working state and changing trend of the real one instantly. Preliminary experiments carried out in Xi’an Coal Mine Machinery Factory show that the 3DVR Digital Platform can be integrated with the remote control system for shearer well. The ability to real-time display of shearer’s working state is better than that in traditional ways, for the information is displayed in the form of data and curve in traditional control and monitoring system for shearer, which is unrealistic to the operator and unsuitable for remote control and monitoring.


Author(s):  
Mingdong Zhou ◽  
Michael Yu Wang ◽  
Li Li

A novel structural optimization method that utilizes both explicit and implicit geometric representations is presented. In this method, an octree grid is adopted to accommodate the free structural interface of an implicit level set model and a corresponding 2-manifold triangle mesh model. Within each iteration of optimization, the interface is evolved implicitly by using a semi-Lagrange level set method, during which the signed distance field is evaluated directly and accurately from the current surface model other than interpolation. After that, another mesh model is extracted from the updated field and serves as the input of subsequent design process. This hybrid and adaptive representation scheme not only achieves “narrow band computation”, but also facilitates the structural analysis by using a geometry-aware mesh-free approach. Moreover, a feature preserving and topological errorless mesh simplification algorithm can also be leveraged to enhance the computational efficiency. A three dimensional benchmark example is provided to demonstrate the capability and potential of this method.


2020 ◽  
Author(s):  
Emmanuel Chané

&lt;p&gt;In this work, the interactions between the solar wind and the magnetosphere of Saturn are studied via state-of-the-art global MHD simulations, focusing on the release of plasmoids in the magnetotail. We analyze in detail the occurrence rate, the size, the speed and the evolution of the plasmoids in the simulations and compare the results with in-situ measurements. In our simulations, the multi-species three-dimensional MHD equations are solved with the code MPI-AMRVAC on a spherical non-uniform mesh ranging from 3 Rs (inner boundary) to 200 Rs (outer boundary). In order to simulate the magnetosphere-ionosphere coupling, to accelerate the ionospheric plasma up to rigid corotation and to close the electrical current systems, ion-neutral collisions are introduced in the MHD equations in the ionospheric region near the inner boundary. The strong mass-loading associated with the moon Enceladus is also included as an axisymmetric torus centered at 5.5 Rs.&lt;/p&gt;


Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7955
Author(s):  
Daniel Jie Yuan Chin ◽  
Ahmad Sufril Azlan Mohamed ◽  
Khairul Anuar Shariff ◽  
Mohd Nadhir Ab Wahab ◽  
Kunio Ishikawa

Three-dimensional reconstruction plays a vital role in assisting doctors and surgeons in diagnosing the healing progress of bone defects. Common three-dimensional reconstruction methods include surface and volume rendering. As the focus is on the shape of the bone, this study omits the volume rendering methods. Many improvements have been made to surface rendering methods like Marching Cubes and Marching Tetrahedra, but not many on working towards real-time or near real-time surface rendering for large medical images and studying the effects of different parameter settings for the improvements. Hence, this study attempts near real-time surface rendering for large medical images. Different parameter values are experimented on to study their effect on reconstruction accuracy, reconstruction and rendering time, and the number of vertices and faces. The proposed improvement involving three-dimensional data smoothing with convolution kernel Gaussian size 5 and mesh simplification reduction factor of 0.1 is the best parameter value combination for achieving a good balance between high reconstruction accuracy, low total execution time, and a low number of vertices and faces. It has successfully increased reconstruction accuracy by 0.0235%, decreased the total execution time by 69.81%, and decreased the number of vertices and faces by 86.57% and 86.61%, respectively.


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