Quadrangular remeshing of triangulated surfaces has received an increasing attention in recent years. A particularly elegant approach is the extraction of quads from the streamlines of a harmonic field. While the construction of such fields is by now a standard technique in geometry processing, enforcing design constraints is still not fully investigated. This work presents a technique for handling directional constraints by directly controlling the gradient of the field. In this way, line constraints sketched by the user or automatically obtained as feature lines can be fulfilled efficiently. Furthermore, we show the potential of quasi-harmonic fields as a flexible tool for controlling the behavior of the field over the surface. Treating the surface as an inhomogeneous domain we can endow specific surface regions with field attraction/repulsion properties.
{"title":"Controlled field generation for quad-remeshing","authors":"O. Schall, Rhaleb Zayer, H. Seidel","doi":"10.1145/1364901.1364942","DOIUrl":"https://doi.org/10.1145/1364901.1364942","url":null,"abstract":"Quadrangular remeshing of triangulated surfaces has received an increasing attention in recent years. A particularly elegant approach is the extraction of quads from the streamlines of a harmonic field. While the construction of such fields is by now a standard technique in geometry processing, enforcing design constraints is still not fully investigated. This work presents a technique for handling directional constraints by directly controlling the gradient of the field. In this way, line constraints sketched by the user or automatically obtained as feature lines can be fulfilled efficiently. Furthermore, we show the potential of quasi-harmonic fields as a flexible tool for controlling the behavior of the field over the surface. Treating the surface as an inhomogeneous domain we can endow specific surface regions with field attraction/repulsion properties.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123276197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Interactive visualization of massive models still remains a challenging problem. This is mainly due to a combination of ever increasing model complexity with the current hardware design trend that leads to a widening gap between slow data access speed and fast data processing speed. We argue that developing efficient data access and data management techniques is key in solving the problem of interactive visualization of massive models. Particularly, we discuss visibility culling, simplification, cache-coherent layouts, and data compression techniques as efficient data management techniques that enable interactive visualization of massive models.
{"title":"Technical strategies for massive model visualization","authors":"E. Gobbetti, D. Kasik, Sung-eui Yoon","doi":"10.1145/1364901.1364960","DOIUrl":"https://doi.org/10.1145/1364901.1364960","url":null,"abstract":"Interactive visualization of massive models still remains a challenging problem. This is mainly due to a combination of ever increasing model complexity with the current hardware design trend that leads to a widening gap between slow data access speed and fast data processing speed. We argue that developing efficient data access and data management techniques is key in solving the problem of interactive visualization of massive models. Particularly, we discuss visibility culling, simplification, cache-coherent layouts, and data compression techniques as efficient data management techniques that enable interactive visualization of massive models.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"157 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115589316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We convert any quad manifold mesh into an at least C1 surface consisting of bi-cubic tensor-product splines with localized perturbations of degree bi-5 near non-4-valent vertices. There is one polynomial piece per quad facet, regardless of the valence of the vertices. Particular care is taken to derive simple formulas so that the surfaces are computed efficiently in parallel and match up precisely when computed independently on the GPU.
{"title":"GPU conversion of quad meshes to smooth surfaces","authors":"A. Myles, Young In Yeo, J. Peters","doi":"10.1145/1364901.1364946","DOIUrl":"https://doi.org/10.1145/1364901.1364946","url":null,"abstract":"We convert any quad manifold mesh into an at least C1 surface consisting of bi-cubic tensor-product splines with localized perturbations of degree bi-5 near non-4-valent vertices. There is one polynomial piece per quad facet, regardless of the valence of the vertices. Particular care is taken to derive simple formulas so that the surfaces are computed efficiently in parallel and match up precisely when computed independently on the GPU.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"65 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115146738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Improving the quality of tetrahedral meshes is an important operation in many scientific computing applications. Meshes with badly shaped elements impact both the accuracy and convergence of scientific applications. State-of-the-art mesh improvement techniques rely on sophisticated numerical optimization methods such as feasible Newton or conjugate gradient. Unfortunately, these methods cannot be practically applied to very large meshes due to their global nature. Our contribution in this paper is to describe a streaming framework for tetrahedral mesh optimization. This framework enables the optimization of meshes an order of magnitude larger than previously feasible, effectively optimizing meshes too large to fit in memory. Our results show that streaming is typically faster than global optimization and results in comparable mesh quality. This leads us to conclude that streaming extends mesh optimization to a new class of mesh sizes without compromising the quality of the optimized mesh.
{"title":"Streaming tetrahedral mesh optimization","authors":"Tian Xia, E. Shaffer","doi":"10.1145/1364901.1364940","DOIUrl":"https://doi.org/10.1145/1364901.1364940","url":null,"abstract":"Improving the quality of tetrahedral meshes is an important operation in many scientific computing applications. Meshes with badly shaped elements impact both the accuracy and convergence of scientific applications. State-of-the-art mesh improvement techniques rely on sophisticated numerical optimization methods such as feasible Newton or conjugate gradient. Unfortunately, these methods cannot be practically applied to very large meshes due to their global nature. Our contribution in this paper is to describe a streaming framework for tetrahedral mesh optimization. This framework enables the optimization of meshes an order of magnitude larger than previously feasible, effectively optimizing meshes too large to fit in memory. Our results show that streaming is typically faster than global optimization and results in comparable mesh quality. This leads us to conclude that streaming extends mesh optimization to a new class of mesh sizes without compromising the quality of the optimized mesh.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126587014","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Johannes Mezger, B. Thomaszewski, S. Pabst, W. Straßer
We present an alternative approach to standard geometric shape editing using physically-based simulation. With our technique, the user can deform complex objects in real-time. The basis of our method is formed by a fast and accurate finite element implementation of an elasto-plastic material model, specifically designed for interactive shape manipulation. Using quadratic shape functions, we reduce approximation errors inherent to methods based on linear finite elements. The physical simulation uses a volume mesh comprised of quadratic tetrahedra, which are constructed from a coarser approximation of the detailed surface. In order to guarantee stability and real-time frame rates during the simulation, we cast the elasto-plastic problem into a linear formulation. For this purpose, we present a corotational formulation for quadratic finite elements. We demonstrate the versatility of our approach in interactive manipulation sessions and show that our animation system can be coupled with further physics-based animations like, e.g. fluids and cloth, in a bi-directional way.
{"title":"Interactive physically-based shape editing","authors":"Johannes Mezger, B. Thomaszewski, S. Pabst, W. Straßer","doi":"10.1145/1364901.1364915","DOIUrl":"https://doi.org/10.1145/1364901.1364915","url":null,"abstract":"We present an alternative approach to standard geometric shape editing using physically-based simulation. With our technique, the user can deform complex objects in real-time. The basis of our method is formed by a fast and accurate finite element implementation of an elasto-plastic material model, specifically designed for interactive shape manipulation. Using quadratic shape functions, we reduce approximation errors inherent to methods based on linear finite elements. The physical simulation uses a volume mesh comprised of quadratic tetrahedra, which are constructed from a coarser approximation of the detailed surface. In order to guarantee stability and real-time frame rates during the simulation, we cast the elasto-plastic problem into a linear formulation. For this purpose, we present a corotational formulation for quadratic finite elements. We demonstrate the versatility of our approach in interactive manipulation sessions and show that our animation system can be coupled with further physics-based animations like, e.g. fluids and cloth, in a bi-directional way.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"28 2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126323556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We discuss the use of subdivision surfaces in the procedural design of imprint rolls for use in the roller imprinting process. Roller imprinting is being developed for the fabrication of microfluidic devices in polymer substrates. Imprint rolls are modeled using Catmull-Clark subdivision surfaces, and are procedurally designed based on feedback from finite-element simulations of the imprinting process. Microfluidic devices exhibit repeating patterns, and can be modeled using a small set of unique entities (or tiles). Imprint rolls are also modeled as a sum of tiles, and rolls are designed by studying the imprinting behavior of clusters of tiles corresponding to the repeating patterns seen in the device. This approach reduces the roll complexity and analysis time. The rolls need to be described in a sufficiently flexible format for the tile-based analysis to be effective. Conventional model representations are too cumbersome for piecewise iterative refinement as they require the manipulation of a large number of variables to modify surface features while preserving continuity. Subdivision surfaces, on the other hand, are naturally continuous and can be modified by manipulating a small number of variables. The ability to apply rule-based, arbitrary refinement on subdivision surfaces makes them especially suitable. The procedural modeling methodology and the subdivision design representation enable the integrated design, analysis, and manufacturing of imprint rolls, and has proven effective in decreasing the design-to-manufacture time of novel microfluidic technology.
{"title":"Subdivision surfaces for procedural design of imprint rolls","authors":"A. Vijayaraghavan, D. Dornfeld","doi":"10.1145/1364901.1364947","DOIUrl":"https://doi.org/10.1145/1364901.1364947","url":null,"abstract":"We discuss the use of subdivision surfaces in the procedural design of imprint rolls for use in the roller imprinting process. Roller imprinting is being developed for the fabrication of microfluidic devices in polymer substrates. Imprint rolls are modeled using Catmull-Clark subdivision surfaces, and are procedurally designed based on feedback from finite-element simulations of the imprinting process. Microfluidic devices exhibit repeating patterns, and can be modeled using a small set of unique entities (or tiles). Imprint rolls are also modeled as a sum of tiles, and rolls are designed by studying the imprinting behavior of clusters of tiles corresponding to the repeating patterns seen in the device. This approach reduces the roll complexity and analysis time. The rolls need to be described in a sufficiently flexible format for the tile-based analysis to be effective. Conventional model representations are too cumbersome for piecewise iterative refinement as they require the manipulation of a large number of variables to modify surface features while preserving continuity. Subdivision surfaces, on the other hand, are naturally continuous and can be modified by manipulating a small number of variables. The ability to apply rule-based, arbitrary refinement on subdivision surfaces makes them especially suitable. The procedural modeling methodology and the subdivision design representation enable the integrated design, analysis, and manufacturing of imprint rolls, and has proven effective in decreasing the design-to-manufacture time of novel microfluidic technology.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"90 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129966274","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present an algorithm for computing the Voronoi cell for a set of planes, spheres and cylinders in R3. The algorithm is based on a lower envelope computation of the bisector surfaces between these primitives, and the projection of the trisector curves onto planes bounding the object for which the Voronoi cell is computed, denoted the base object. We analyze the different bisectors and trisectors that can occur in the computation. Our analysis shows that most of the bisector surfaces are quadric surfaces and five of the ten possible trisectors are conic section curves. We have implemented our algorithm using the IRIT library and the CGAL 3D lower envelope package. All presented results are from our implementation.
{"title":"Computing the Voronoi cells of planes, spheres and cylinders in R3","authors":"Iddo Hanniel, G. Elber","doi":"10.1145/1364901.1364911","DOIUrl":"https://doi.org/10.1145/1364901.1364911","url":null,"abstract":"We present an algorithm for computing the Voronoi cell for a set of planes, spheres and cylinders in R3. The algorithm is based on a lower envelope computation of the bisector surfaces between these primitives, and the projection of the trisector curves onto planes bounding the object for which the Voronoi cell is computed, denoted the base object. We analyze the different bisectors and trisectors that can occur in the computation. Our analysis shows that most of the bisector surfaces are quadric surfaces and five of the ten possible trisectors are conic section curves. We have implemented our algorithm using the IRIT library and the CGAL 3D lower envelope package. All presented results are from our implementation.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128290163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We introduce a method for extracting boundary surfaces from volumetric models of mechanical parts by X-ray CT scanning. When the volumetric model is composed of two materials, one for the object and the other for the background (Air), these boundary surfaces can be extracted as isosurfaces using a contouring method such as Marching Cubes [Lorensen and Cline 1987]. For a volumetric model composed of more than two materials, we need to classify the voxel types into segments by material and use a generalized Marching Cubes algorithm that can deal with both CT values and material types. Here we propose a method for precisely classifying the volumetric model into its component materials using a modified and combined method of two well-known algorithms in image segmentation, region growing and Graph-cut. We then apply the generalized Marching Cubes algorithm to generate triangulated mesh surfaces. In addition, we demonstrate the effectiveness of our method by constructing high-quality triangular mesh models of the segmented parts.
介绍了一种利用x射线CT扫描从机械零件的体积模型中提取边界面的方法。当体积模型由两种材料组成时，一种材料用于物体，另一种材料用于背景(空气)，这些边界表面可以使用诸如Marching Cubes的等高线方法作为等值面提取[Lorensen and Cline 1987]。对于由两种以上材料组成的体积模型，我们需要将体素类型按材料分类，并使用可以处理CT值和材料类型的广义行军立方体算法。本文提出了一种将两种著名的图像分割算法(区域生长算法和图切算法)进行改进和组合的方法来精确地将体积模型分类到其组成材料中。然后，我们应用广义行军立方体算法生成三角网格曲面。此外，通过构建高质量的三角网格模型，验证了该方法的有效性。
{"title":"Extraction of isosurfaces from multi-material CT volumetric data of mechanical parts","authors":"M. Shammaa, Hiromasa Suzuki, Y. Ohtake","doi":"10.1145/1364901.1364931","DOIUrl":"https://doi.org/10.1145/1364901.1364931","url":null,"abstract":"We introduce a method for extracting boundary surfaces from volumetric models of mechanical parts by X-ray CT scanning. When the volumetric model is composed of two materials, one for the object and the other for the background (Air), these boundary surfaces can be extracted as isosurfaces using a contouring method such as Marching Cubes [Lorensen and Cline 1987]. For a volumetric model composed of more than two materials, we need to classify the voxel types into segments by material and use a generalized Marching Cubes algorithm that can deal with both CT values and material types. Here we propose a method for precisely classifying the volumetric model into its component materials using a modified and combined method of two well-known algorithms in image segmentation, region growing and Graph-cut. We then apply the generalized Marching Cubes algorithm to generate triangulated mesh surfaces. In addition, we demonstrate the effectiveness of our method by constructing high-quality triangular mesh models of the segmented parts.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"03 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129318258","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In recent years, there has been an increasing interest in developing geometric algorithms for kinematic computations. The aim of this paper is to present the notion of kinematic convexity as a key element for a new framework for spherical kinematic geometry that allows for the development of more elegant and efficient algorithms for geometric computations in kinematic applications. The resulting framework, called computational spherical kinematic geometry, is developed by combining the oriented projective geometry with the kinematic geometry of spherical motions. By extending the idea of convexity in affine geometry to an oriented image space of spherical displacements, the notion of kinematic convexity is proposed. A novel application to the collision prediction problem is presented to illustrate the theory developed.
{"title":"Kinematic convexity of spherical displacements and its application to collision prediction","authors":"Q. Ge, A. Purwar, Jun Wu","doi":"10.1145/1364901.1364955","DOIUrl":"https://doi.org/10.1145/1364901.1364955","url":null,"abstract":"In recent years, there has been an increasing interest in developing geometric algorithms for kinematic computations. The aim of this paper is to present the notion of kinematic convexity as a key element for a new framework for spherical kinematic geometry that allows for the development of more elegant and efficient algorithms for geometric computations in kinematic applications. The resulting framework, called computational spherical kinematic geometry, is developed by combining the oriented projective geometry with the kinematic geometry of spherical motions. By extending the idea of convexity in affine geometry to an oriented image space of spherical displacements, the notion of kinematic convexity is proposed. A novel application to the collision prediction problem is presented to illustrate the theory developed.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126338892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a novel computational framework based on dynamic spherical volumetric simplex splines for simulation of genuszero real-world objects. In this framework, we first develop an accurate and efficient algorithm to reconstruct the high-fidelity digital model of a real-world object with spherical volumetric simplex splines which can represent with accuracy geometric, material, and other properties of the object simultaneously. With the tight coupling of Lagrangian mechanics, the dynamic volumetric simplex splines representing the object can accurately simulate its physical behavior because it can unify the geometric and material properties in the simulation. The visualization can be directly computed from the object's geometric or physical representation based on the dynamic spherical volumetric simplex splines during simulation without interpolation or resampling. We have applied the framework for biomechanic simulation of brain deformations, such as brain shifting during the surgery and brain injury under blunt impact. We have compared our simulation results with the ground truth obtained through intra-operative magnetic resonance imaging and the real biomechanic experiments. The evaluations demonstrate the excellent performance of our new technique presented in this paper.
{"title":"Dynamic spherical volumetric simplex splins with application in biomedical simulation","authors":"Y. Tan, Jing Hua, Hong Qin","doi":"10.1145/1364901.1364917","DOIUrl":"https://doi.org/10.1145/1364901.1364917","url":null,"abstract":"This paper presents a novel computational framework based on dynamic spherical volumetric simplex splines for simulation of genuszero real-world objects. In this framework, we first develop an accurate and efficient algorithm to reconstruct the high-fidelity digital model of a real-world object with spherical volumetric simplex splines which can represent with accuracy geometric, material, and other properties of the object simultaneously. With the tight coupling of Lagrangian mechanics, the dynamic volumetric simplex splines representing the object can accurately simulate its physical behavior because it can unify the geometric and material properties in the simulation. The visualization can be directly computed from the object's geometric or physical representation based on the dynamic spherical volumetric simplex splines during simulation without interpolation or resampling. We have applied the framework for biomechanic simulation of brain deformations, such as brain shifting during the surgery and brain injury under blunt impact. We have compared our simulation results with the ground truth obtained through intra-operative magnetic resonance imaging and the real biomechanic experiments. The evaluations demonstrate the excellent performance of our new technique presented in this paper.","PeriodicalId":216067,"journal":{"name":"Symposium on Solid and Physical Modeling","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2008-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121588181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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