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Flattening triangulated surfaces using a mass-spring model

INTERNATIONAL JOURNAL OF ADVANCED MANUFACTURING TECHNOLOGY 2005年第1-2期25卷 108-117页

作者： Li, JT Zhang, DL Lu, GD Peng, YY Wen, X Sakaguti, Y Digital Fash Ltd Osaka Japan Zhejiang Univ State Key Lab CAD&CG Hangzhou 310027 Peoples R China

Flattening 3D surfaces is a challenging problem in the product design community. This paper presents an efficient flattening algorithm using a mass-spring model. In the mass spring model, crossed-springs are introduced to reduce the distortion of the resulting surface. The process of planar development is made faster by using triangle strips. To solve the problem of overlapping, the paper proposes a constrained flattening iteration method and a local correction method. Experimental results show that the algorithm can deal with complex surfaces efficiently.

关键词： mass-spring model overlap correction surface flattening triangle strip

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An Optimized mass-spring model with Shape Restoration Ability Based on Volume Conservation

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KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS 2020年第4期14卷 1738-1756页

作者： Zhang, Xiaorui Wu, Hailun Sun, Wei Yuan, Chengsheng Nanjing Univ Informat Sci & Technol Sch Comp & Software Engn Res Ctr Digital Forens Jiangsu Engn Ctr Network MonitoringMinist Educ Nanjing 210044 Peoples R China Nanjing Univ Informat Sci & Technol Jiangsu Collaborat Innovat Ctr Atmospher Environm Nanjing 210044 Peoples R China

To improve the accuracy and realism of the virtual surgical simulation system, this paper proposes an optimized mass-spring model with shape restoration ability based on volume conservation to simulate soft tissue deformation. The proposed method constructs a soft tissue surface model that adopts a new flexion spring for resisting bending and incorporates it into the mass-spring model (MSM) to restore the original shape. Then, we employ the particle swarm optimization algorithm to achieve the optimal solution of the model parameters. Besides, the volume conservation constraint is applied to the position-based dynamics (PBD) approach to maintain the volume of the deformable object for constructing the soft tissue volumetric model base on tetrahedrons. Finally, we built a simulation system on the PHANTOM OMNI force tactile interaction device to realize the deformation simulation of the virtual liver. Experimental results show that the proposed model has a good shape restoration ability and incompressibility, which can enhance the deformation accuracy and interactive realism.

关键词： Virtual surgery soft tissue deformation mass-spring model position-based dynamics particle swarm optimization algorithm

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Improved equivalent mass-spring model for seismic response analysis of two-dimensional soil strata

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SOIL DYNAMICS AND EARTHQUAKE ENGINEERING 2018年 112卷 198-202页

作者： Li, Chong Yuan, Yong He, Pengfei Yuan, Juyun Yu, Haitao Tongji Univ Sch Aerosp Engn & Appl Mech Shanghai 200092 Peoples R China Tongji Univ State Key Lab Disaster Reduct Civil Engn Shanghai 200092 Peoples R China Tongji Univ Minist Educ Key Lab Geotech & Underground Engn Shanghai 200092 Peoples R China

This paper presents an improved development of the mass-spring model initially proposed by Okamoto and Tamura for seismic response analysis of two-dimensional soil strata. The new model is based on the mode equivalence method and is constructed as a two-dimensional equivalent multi-degree-of-freedom (MDOF) system. Physical parameters of the model are derived and formulated in terms of modal properties. Dynamic response of the model from inclined SH-waves is obtained and the accuracy and validity are confirmed by comparing with the solution of wave propagation. The improved model is further discussed through a performance comparison with the mass-spring model.

关键词： Seismic analysis Mode equivalence MDOF system mass-spring model Amplification

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Structural deformation behavior of Jacquardtronic lace based on the mass-spring model

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TEXTILE RESEARCH JOURNAL 2017年第10期87卷 1242-1250页

作者： Li, Xinxin Zhang, Aijun Ma, Pibo Cong, Honglian Jiang, Gaoming Jiangnan Univ 1800 Lihu Ave Wuxi 214122 Jiangsu Peoples R China

To simulate the structural deformation behavior of Jacquardtronic lace, which is formed on a multibar Jacquard Raschel machine and is widely used in female fashion, the key influencing factors on structural deformation were introduced and a tailored mass-spring model was built in which the lace was considered to be numbers of evenly distributed particles connected by elastane springs. These springs covered structural springs, restriction springs and spiral springs, respectively, created for ground pillars, Jacquard inlays, pattern lapping and elastane yarns. The elastane force on particles was analyzed to study motion state and deformation behavior with the explicit Euler method. The deformation simulated models were implemented by a simulator program via Visual C++ and were tested with a lace sample. Particular attention was paid to analyzing the effect of Jacquard structures and yarn tension on deformation and the detection model was introduced to avoid improper deformation caused by excessive yarn tension. The simulation results showed practicability and efficiency when compared with the real sample.

关键词： warp-knitting Jacquardtronic lace mass-spring model deformation behavior explicit Euler method

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A Three-Stage Cutting Simulation System Based on mass-spring model

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Computer modeling in Engineering & Sciences 2021年第4期127卷 117-133页

作者： Xiaorui Zhang Jiali Duan Wei Sun Tong Xu Sunil Kumar Jha Jiangsu Engineering Center of Network Monitoring Engineering Research Center of Digital ForensicsMinistry of EducationSchool of Computer and SoftwareNanjing University of Information Science&TechnologyNanjing210044China Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET) Nanjing University of Information Science&TechnologyNanjing210044China Faculty of Information Technology University of Information Technology and ManagementRzeszow35-225Poland

The cutting simulation of soft tissue is important in virtual *** includes three major challenges in computation:Soft tissue simulation,collision detection,and handling,as well as soft tissue *** order to address the earlier challenges,we propose a virtual cutting system based on the mass-spring *** this system,MSM is utilized to simulate the soft tissue *** stress is introduced to the model for simulating the shrinking effect of soft tissue in ***,a cylinder-based collision detection method is used to supervise the collision between surgical tools and soft ***,we simulate the cutting operation with a three-stage cutting method with swept volume,B´ezier curve,and an algorithm named shortest distance nodes matching *** order to verify the system performance,we carry out three validation experiments on the proposed system:Cutting accuracy experiment,collision detection validation,and practical cutting *** indicate that our system can well perform the shrinking effect of soft tissue in *** system has fast and accurate collision ***,the system can reconstruct smooth incisions vividly.

关键词： mass-spring model collision algorithm virtual surgery soft tissue simulation

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MECHANICAL mass-spring model FOR UNDERSTANDING GLOBULAR MOTION OF PROTEINS

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JOURNAL OF MECHANICS 2016年第2期32卷 123-129页

作者： Kim, J-I. Eom, K. Na, S. Korea Univ Dept Mech Engn Seoul South Korea Sungkyunkwan Univ Coll Sport Sci Suwon South Korea

The conformational (structural) change of proteins plays an essential role in their functions. Experiments have been conducted to try to understand the conformational change of proteins, but they have not been successful in providing information on the atomic scale. Simulation methods have been developed to understand the conformational change at an atomic scale in detail. Coarse-grained methods have been developed to calculate protein dynamics with computational efficiency when compared with than all atom models. A structure-based mass-spring model called the elastic network model (ENM) showed excellent performance in various protein studies. Coarse-grained ENM was modified in various ways to improve the computational efficiency, and consequently to reduce required computational cost for studying the large-scale protein structures. Our previous studies report a modified mass-spring model, which was developed based on condensation method applicable to ENM, and show that the model is able to accurately predict the fluctuation behavior of proteins. We applied this modified mass-spring model to analyze the conformational changes in proteins. We consider two model proteins as an example, where these two proteins exhibit different functions and molecular sizes. It is shown that the modified mass spring model allows for accurately predicting the pathways of conformation changes for proteins. Our model provides structural insights into the conformation change of proteins related to the biological functions of late protein complexes.

关键词： mass-spring model Condensation method Normal mode analysis Conformation change

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A multi-tissue mass-spring model for computer assisted breast surgery

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MEDICAL ENGINEERING & PHYSICS 2013年第1期35卷 47-53页

作者： Patete, Paolo Iacono, Maria Ida Spadea, Maria Francesca Trecate, Giovanna Vergnaghi, Daniele Mainardi, Luca Tommaso Baroni, Guido Politecn Milan Dept Bioengn I-20133 Milan Italy Magna Graecia Univ Catanzaro Dept Expt & Clin Med Catanzaro Italy Natl Canc Inst Dept Imaging Diag & Radiotherapy I-20133 Milan Italy

The aim of this work was to develop and validate a 3D female breast deformation model for computer assisted breast surgery. Magnetic resonance (MR) image data of a patient undergoing breast biopsy, were acquired using two different protocols with the patient in prone position: (i) uncompressed breast and (ii) compressed breast, with lateral single breast compression, realized with a movable slab. The acquired images were then segmented using a semi-automatic procedure and from the extracted volumes of interest tetrahedral meshes representing skin, fat and mammary glands were generated. Tissue deformation was ruled by a mass-spring model: first, an iterative approximation algorithm was implemented to estimate the spring's rest length and stiffness, accounting for gravity force;then the resulting parameters were used to deform the uncompressed breast model in order to reach the real compressed one (ground truth). Results showed that gravity force applied to the mesh was properly compensated by the internal elastic forces, leading to a distance between the deformed mesh and the reference data of 0.036 +/- 0.092 mm (median inter quartile range). The point to mesh residual distance between the deformed mesh and the ground truth was 1.224 +/- 2.202 mm (median +/- inter quartile range). Further investigation on a larger patient dataset is required for a more robust confirmation of model accuracy in predicting breast deformations. (c) 2012 IPEM. Published by Elsevier Ltd. All rights reserved.

关键词： Breast modeling mass-spring model Computer assisted surgery Breast deformation Breast biopsy Mechanical model

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Optimization of mass-spring model Parameters by ICA for Assessing Compressional Behavior of Warp-knitted Spacer Fabrics Reinforced Polyurethane Cast Elastomer Composites

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FIBERS AND POLYMERS 2022年第13期23卷 3596-3605页

作者： Payvandy, Pedram Ahmadi, Mohammad Saleh Yousefpour, Masih Yazd Univ Dept Text Engn Yazd 89195741 Iran

Warp knitted spacer fabrics (WKSFs) have been developed for many applications such as cushioning materials. Therefore, the study on the compressional behavior of WKSFs and their composites is of great importance. In this study, six types of mass-spring models, i.e. Maxwell, Kelvin, Standard linear, Burger, linear spring, and non-linear spring are used to estimate compressional behavior of WKSF reinforced polyurethane cast elastomer composites under flat and spherical types of loading. Imperialist Competitive Algorithm (ICA) is utilized to predict models' parameters for minimizing the differences between experimental and theoretical data. The best results were obtained by the non-linear spring model with the mean error of 4.12 % and 3.37 % for flat and spherical compression, respectively. The mean of errors of the other models were higher than 14.75 %. It is proved that the compression force-displacement curves of the samples in both flat and spherical loading follow exponential forms.

关键词： Warp knitted spacer fabric Composite Compression mass-spring model ICA

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Maxillofacial surgery simulation using a mass-spring model derived from continuum and the scaled displacement method

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INTERNATIONAL JOURNAL OF COMPUTER ASSISTED RADIOLOGY AND SURGERY 2009年第1期4卷 89-98页

作者： San Vicente, G. Buchart, C. Borro, D. Celigueeta, J. T. TECNUN Univ Navarra CEIT San Sebastian 20018 Spain

Purpose Development of a maxillofacial surgery simulation software capable of predicting a patient's appearance after surgery. Methods We have derived a new mass-spring model (MSM) equivalent to a linear finite element (FE) model for cubic elements. In addition, we propose the scaled displacement method as a new method to perform the simulation more realistically. Results The average error of eight soft tissue landmarks measured between 0.37 and 2.01 mm except from a landmark that had an error of 4.44 mm;values close to those obtained with the linear FE method. On the other hand, the scaled displacement method allows avoiding punctual stress concentration and bending effects making a much more realistic simulation in the region of the bone cut. Conclusions Good results have been achieved with our two proposed methods. In addition, the simple way in which MSM can be parallelized makes it an interesting alternative to FE method.

关键词： Maxillofacial surgery mass-spring model Finite element method Scaled displacement method Computer simulation

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ENDOSCOPIC IMAGE CUTTING SIMULATION BASED ON mass-spring model AND COMPUTATIONAL GEOMETRY

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JOURNAL OF CIRCUITS SYSTEMS AND COMPUTERS 2009年第8期18卷 1453-1465页

作者： Yuan, Zhiyong Feng, Shikun Yin, Qian Wang, Xiali Zhang, Dengyi Zhao, Jianhui Chen, Mianyun Wuhan Univ Sch Comp Sci Wuhan 430072 Hubei Peoples R China Beijing Normal Univ Coll Informat Sci & Technol Beijing 100875 Peoples R China Huazhong Univ Sci & Technol Dept Control Sci & Engn Wuhan 430074 Hubei Peoples R China

As minimally invasive surgical techniques become widely known to patients, medical training systems based on virtual simulation are highly desired. These systems help surgeon trainees to acquire, practice and evaluate their surgical skills. A key component in a virtual training system is to simulate the dynamics that occur in surgical procedures. Tissue cutting, as a common phenomenon during surgery, has attracted many research efforts in computer simulation. In this paper, we propose an approach to endoscopic image cutting simulation which is based on both mass-spring model and Computational Geometry. In the cutting simulation model, the springs to be cut off are imagined into line segments. In the calculation of the elastic force on mass points, we have found that whether some adjacent springs of a mass point to be eliminated or not during a cutting is critical. If a spring intersects the cutting plane, we set the elastic force of this spring to zero. We adopted properties of cross product and related algorithms (the rapid exclusion test, the crossover test) in Computational Geometry to determine the springs that are intersected with the cutting plane. And then, we utilized the bilinear interpolation and OpenGL techniques to render the cutting procedure of the soft tissue. The experimental results show that our cutting simulation is effective and practical.

关键词： Cutting simulation mass-spring model cross product cutting plane

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