Automatic and High-Quality Surface Mesh Generation for CAD Models
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Studio Toolkit for Flexibles 14 User Guide
Studio Toolkit for Flexibles 14 User Guide 06 - 2015 Studio Toolkit for Flexibles Contents 1. Copyright Notice.......................................................................................................................................................................... 4 2. Introduction.....................................................................................................................................................................................6 2.1 About Studio....................................................................................................................................................................... 6 2.2 Workflow and Concepts................................................................................................................................................. 7 2.3 Quick-Start Tutorial...........................................................................................................................................................8 3. Creating a New Bag.................................................................................................................................................................12 3.1 Pillow Bags........................................................................................................................................................................13 3.1.1 Panel Order and Fin vs. Lap Seals.............................................................................................................14 3.2 Gusseted Bags.................................................................................................................................................................15 -
Compression and Streaming of Polygon Meshes
Compression and Streaming of Polygon Meshes by Martin Isenburg A dissertation submitted to the faculty of the University of North Carolina at Chapel Hill in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Computer Science. Chapel Hill 2005 Approved by: Jack Snoeyink, Advisor Craig Gotsman, Reader Peter Lindstrom, Reader Dinesh Manocha, Committee Member Ming Lin, Committee Member ii iii ABSTRACT MARTIN ISENBURG: Compression and Streaming of Polygon Meshes (Under the direction of Jack Snoeyink) Polygon meshes provide a simple way to represent three-dimensional surfaces and are the de-facto standard for interactive visualization of geometric models. Storing large polygon meshes in standard indexed formats results in files of substantial size. Such formats allow listing vertices and polygons in any order so that not only the mesh is stored but also the particular ordering of its elements. Mesh compression rearranges vertices and polygons into an order that allows more compact coding of the incidence between vertices and predictive compression of their positions. Previous schemes were designed for triangle meshes and polygonal faces were triangulated prior to compression. I show that polygon models can be encoded more compactly by avoiding the initial triangulation step. I describe two compression schemes that achieve better compression by encoding meshes directly in their polygonal representation. I demonstrate that the same holds true for volume meshes by extending one scheme to hexahedral meshes. Nowadays scientists create polygonal meshes of incredible size. Ironically, com- pression schemes are not capable|at least not on common desktop PCs|to deal with giga-byte size meshes that need compression the most. -
Mesh Compression
Mesh Compression Dissertation der Fakult¨at f¨ur Informatik der Eberhard-Karls-Universit¨at zu T¨ubingen zur Erlangung des Grades eines Doktors der Naturwissenschaften (Dr. rer. nat.) vorgelegt von Dipl.-Inform. Stefan Gumhold aus Tubingen¨ Tubingen¨ 2000 Tag der m¨undlichen Qualifikation: 19.Juli 2000 Dekan: Prof. Dr. Klaus-J¨orn Lange 1. Berichterstatter: Prof. Dr.-Ing. Wolfgang Straßer 2. Berichterstatter: Prof. Jarek Rossignac iii Zusammenfassung Die Kompression von Netzen ist eine weitgef¨acherte Forschungsrichtung mit Anwen- dungen in den verschiedensten Bereichen, wie zum Beispiel im Bereich der Hand- habung extrem großer Modelle, beim Austausch von dreidimensionalem Inhaltuber ¨ das Internet, im elektronischen Handel, als anpassungsf¨ahige Repr¨asentation f¨ur Vo- lumendatens¨atze usw. In dieser Arbeit wird das Verfahren der Cut-Border Machine beschrieben. Die Cut-Border Machine kodiert Netze, indem ein Teilbereich durch das Netz w¨achst (region growing). Kodiert wird die Art und Weise, wie neue Netzele- mente dem wachsenden Teilbereich einverleibt werden. Das Verfahren der Cut-Border Machine kann sowohl auf Dreiecksnetze als auch auf Tetraedernetze angewendet wer- den. Trotz der einfachen Struktur des Verfahrens kann eine sehr hohe Kompression- srate erzielt werden. Im Falle von Tetraedernetzen erreicht die Cut-Border Machine die beste Kompressionsrate von allen bekannten Verfahren. Die einfache Struktur der Cut-Border Machine erm¨oglicht einerseits die Realisierung direkt in Hardware und ist auch als Implementierung in Software extrem schnell. Auf der anderen Seite erlaubt die Einfachheit eine theoretische Analyse des Algorithmus. Gezeigt werden konnte, dass f¨ur ebene Triangulierungen eine leicht modifizierte Version der Cut-Border Machine lineare Laufzeiten in der Zahl der Knoten erzielt und dass die komprimierte Darstellung nur linearen Speicherbedarf ben¨otigt, d.h. -
Meshes and More CMSC425.01 Fall 2019 Administrivia
Meshes and More CMSC425.01 fall 2019 Administrivia • Google form distributed for grading issues Today’s question How to represent objects Polygonal meshes • Standard representation of 3D assets • Questions: • What data and how stored? • How generate them? • How color and render them? Data structure • Geometric information • Vertices as 3D points • Topology information • Relationships between vertices • Edges and faces Vertex and fragment shaders • Mapping triangle to screen • Map and color vertices • Vertex shaders in 3D • Assemble into fragments • Render fragments • Fragment shaders in 2D Normals and shading – shading equation • Light eQuation • k terms – color of object • L terms – color of light • Ambient term - ka La • Constant at all positions • Diffuse term - kd (n • l) • Related to light direction • Specular term - (v • r)Q • Related to light, viewer direction Phong exponent • Powers of cos (v • r)Q • v and r normalized • Tightness of specular highlights • Shininess of object Normals and shading • Face normal • One per face • Vertex normal • One per vertex. More accurate • Interpolation • Gouraud: Shade at vertices, interpolate • Phong: Interpolate normals, shade Texture mapping • Vary color across figure • ka, kd and ks terms • Interpolate position inside polygon to get color • Not trivial! • Mapping complex Bump mapping • “Texture” map of • Perturbed normals (on right) • Perturbed height (on left) Summary – full polygon mesh asset • Mesh can have vertices, faces, edges plus normals • Material shader can have • Color (albedo) • -
MASTER THESIS Generating Hollow Offset Surface Meshes From
Department of Information and Computing Sciences Utrecht University The Netherlands MASTER THESIS ICA-3746356 Generating hollow offset surface meshes from segmented CT volumes using distance fields Submitted on 20th August 2019 By M.F.A. Martens Project supervisor (first examiner): prof. dr. R.C. Veltkamp Second examiner: dr. ir. A.F. van der Stappen Daily supervisor: Jan de Vaan Abstract We propose a method to generate hollow offset surface meshes from CT data using distance fields, in general and in the context of the 3mensio software package. Our method improves on several shortcomings of the currently implemented morpholo- gical offsetting method, like a blocky appearance of the offset surface, and uneven distance between the original surface and the offset surface. Our distance field ap- proach is very robust, and performs consistently for a wide range of tested anatomy and across different levels of CT voxel scaling. Our new method is able to return an offset mesh from CT segmentation data in an acceptable amount of time: mostly below 20 seconds, even for very large segmentations. Acknowledgements I want to thank 3mensio Medical Imaging B.V, and my daily supervisor Jan de Vaan in particular, for providing the opportunity to do an internship at their company, and for the support throughout the writing of this thesis report. I also want to thank my main supervisor and first examiner, prof. dr. Remco Veltkamp, for the help with all of my questions and for the feedback on earlier versions of this report. Also I would like to thank dr. ir. Frank van der Stappen, who agreed to by my second examiner. -
Openscad User Manual (PDF)
OpenSCAD User Manual Contents 1 Introduction 1.1 Additional Resources 1.2 History 2 The OpenSCAD User Manual 3 The OpenSCAD Language Reference 4 Work in progress 5 Contents 6 Chapter 1 -- First Steps 6.1 Compiling and rendering our first model 6.2 See also 6.3 See also 6.3.1 There is no semicolon following the translate command 6.3.2 See Also 6.3.3 See Also 6.4 CGAL surfaces 6.5 CGAL grid only 6.6 The OpenCSG view 6.7 The Thrown Together View 6.8 See also 6.9 References 7 Chapter 2 -- The OpenSCAD User Interface 7.1 User Interface 7.1.1 Viewing area 7.1.2 Console window 7.1.3 Text editor 7.2 Interactive modification of the numerical value 7.3 View navigation 7.4 View setup 7.4.1 Render modes 7.4.1.1 OpenCSG (F9) 7.4.1.1.1 Implementation Details 7.4.1.2 CGAL (Surfaces and Grid, F10 and F11) 7.4.1.2.1 Implementation Details 7.4.2 View options 7.4.2.1 Show Edges (Ctrl+1) 7.4.2.2 Show Axes (Ctrl+2) 7.4.2.3 Show Crosshairs (Ctrl+3) 7.4.3 Animation 7.4.4 View alignment 7.5 Dodecahedron 7.6 Icosahedron 7.7 Half-pyramid 7.8 Bounding Box 7.9 Linear Extrude extended use examples 7.9.1 Linear Extrude with Scale as an interpolated function 7.9.2 Linear Extrude with Twist as an interpolated function 7.9.3 Linear Extrude with Twist and Scale as interpolated functions 7.10 Rocket 7.11 Horns 7.12 Strandbeest 7.13 Previous 7.14 Next 7.14.1 Command line usage 7.14.2 Export options 7.14.2.1 Camera and image output 7.14.3 Constants 7.14.4 Command to build required files 7.14.5 Processing all .scad files in a folder 7.14.6 Makefile example 7.14.6.1 Automatic -
Notes on Polygon Meshes 1 Basic Definitions
CMSC 23700 Introduction to Computer Graphics Handout 2 Autumn 2015 November 12 Notes on polygon meshes 1 Basic definitions Definition 1 A polygon mesh (or polymesh) is a triple (V; E; F ), where V a set of vertices (points in space) E ⊂ (V × V ) a set of edges (line segments) F ⊂ E∗ a set of faces (convex polygons) with the following properties: 1. for any v 2 V , there exists (v1; v2) 2 E such that v = v1 or v = v2. 2. for and e 2 E, there exists a face f 2 F such that e is in f. 3. if two faces intersect in space, then the vertex or edge of intersection is in the mesh. If all of the faces of a polygon mesh are triangles, then we call it a triangle mesh (trimesh). Polygons can be tessellated to form triangle meshes. Definition 2 We classify edges in a mesh based on the number of faces they are part of: • A boundary edge is part of exactly one face. • An interior edge is part of two or more faces. • A manifold edge is part of exactly two faces. • A junction edge is part of three or more faces. Junction edges are to be avoided; they can cause cracks when rendering the mesh. Definition 3 A polymesh is connected if the undirected graph G = (VF ;EE), called the dual graph, is connected, where • VF is a set of graph vertices corresponding to the faces of the mesh and • EE is a set of graph edges connecting adjacent faces. -
From Segmented Images to Good Quality Meshes Using Delaunay Refinement
Mesh generation Applications CGAL-mesh From Segmented Images to Good Quality Meshes using Delaunay Refinement Jean-Daniel Boissonnat INRIA Sophia-Antipolis Geometrica Project-Team Emerging Trends in Visual Computing From Segmented Images to Good Quality Meshes Grid-based methods (MC and variants) I Produces unnecessarily large meshes I Regularization and decimation are difficult tasks I Imposes dominant axis-aligned edges Mesh generation Applications CGAL-mesh A determinant step towards numerical simulations Challenges I Quality of the mesh : accurary, topological correctness, size and shape of the elements I Number of elements, processing time I Robustness issues Emerging Trends in Visual Computing From Segmented Images to Good Quality Meshes Mesh generation Applications CGAL-mesh A determinant step towards numerical simulations Challenges I Quality of the mesh : accurary, topological correctness, size and shape of the elements I Number of elements, processing time I Robustness issues Grid-based methods (MC and variants) I Produces unnecessarily large meshes I Regularization and decimation are difficult tasks I Imposes dominant axis-aligned edges Emerging Trends in Visual Computing From Segmented Images to Good Quality Meshes Mesh generation Applications CGAL-mesh Affine Voronoi diagrams and Delaunay triangulations Emerging Trends in Visual Computing From Segmented Images to Good Quality Meshes Mesh generation Applications CGAL-mesh Mesh generation by Delaunay refinement A simple greedy technique that goes back to the early 80’s [Frey, Hermeline] -
Geometry & Computation for Interactive Simulation
Geometry & Computation for Interactive Simulation Jorg Peters (CISE University of Florida, USA), Dinesh Pai (University of British Columbia), Ulrich Reif (Technische Universitaet Darmstadt) Sep 24 – Sep 29, 2017 1 Overview The workshop advanced the state of the art in geometry and computation for interactive simulation by in- troducing to each other researchers from different branches of academia, research labs and industry. These researchers share the common goal of improving the interface between geometry and computation for physi- cal simulation – but approach it with differing emphasis, techniques and toolkits. A key issue for all partici- pants is to shorten process times and to improve the outcomes of the design-analysis cycle. That is, to more quickly optimize shape, structure and properties to achieve one or multiple design goals. Correspondingly, the challenges laid out covered a wide spectrum from hierarchical design and prediction of novel 3D printed materials, to multi-objective optimization minimizing fuel consumption of commercial airplanes, to creating training scenarios for minimally invasive surgery, to multi-point interactive force feedback for virtually plac- ing an engine into a restricted cavity. These challenges map to challenges in the underlying areas of geometry processing, computational geometry, geometric design, formulation of simulation models, isogeometric and higher-order isoparametric design with splines and meshingless approaches, to real-time computation for interactive surgical force-feedback simulation. The workshop was highly succesful in presenting and con- trasting this rich set of techniques. And it generated recommendations for educating future generation of researchers in geometry and computation for interactive simulation (see outcomes). The lower than usual number of participants (due to a second series of earth quakes just before the meeting) allowed for increased length of individual presentations, so as to discuss topics and ideas at length, and to address basics theory. -
An Adaptable and Extensible Geometry Kernel
An Adaptable and Extensible Geometry Kernel ¾ ¿ Susan Hert ½ , Michael Hoffmann , Lutz Kettner , ½ Sylvain Pion , and Michael Seel ½ Max-Planck-Institut fur ¨ Informatik, Stuhlsatzenhausweg 85 66123 Saarbrucken, ¨ Germany. Email: [hert|seel]@mpi-sb.mpg.de. ¾ Institute for Theoretical Computer Science, ETH Zurich, CH-8092 Zurich, Switzerland. Email: [email protected]. ¿ University of North Carolina at Chapel Hill, USA. Email: [email protected]. INRIA, Sophia Antipolis - France. Email: [email protected]. Abstract. Geometric algorithms are based on geometric objects such as points, lines and circles. The term kernel refers to a collection of representations for constant- size geometric objects and operations on these representations. This paper describes how such a geometry kernel can be designed and implemented in C++, having spe- cial emphasis on adaptability, extensibility and efficiency. We achieve these goals fol- lowing the generic programming paradigm and using templates as our tools. These ideas are realized and tested in CGAL [10], the Computational Geometry Algorithms Library. Keywords: Computational geometry, library design, generic programming. 1 Introduction Geometric algorithms that manipulate constant-size objects such as circles, lines, and points are usually described independent of any particular representation of the ob- jects. It is assumed that these objects have certain operations defined on them and that simple predicates exist that can be used, for example, to compare two objects or to determine their relative position. Algorithms are described in this way because all representations are equally valid as far as the correctness of an algorithm is concerned. Also, algorithms can be more concisely described and are more easily seen as being applicable in many settings when they are described in this more generic way. -
Openscad User Manual/Print Version Table of Contents Introduction First
OpenSCAD User Manual/Print version Table of Contents 1. Introduction 2. First Steps 3. The OpenSCAD User Interface 4. The OpenSCAD Language 1. General 2. Mathematical Operators 3. Mathematical Functions 4. String Functions 5. Primitive Solids 6. Transformations 7. Conditional and Iterator Functions 8. CSG Modelling 9. Modifier Characters 10. Modules 11. Include Statement 12. Other Language Feature 5. Using the 2D Subsystem 1. 2D Primitives 2. 3D to 2D Projection 3. 2D to 2D Extrusion 4. DXF Extrusion 5. Other 2D formats 6. STL Import and Export 1. STL Import 2. STL Export 7. Commented Example Projects 8. Using OpenSCAD in a command line environment 9. Building OpenSCAD from Sources 1. Building on Linux/UNIX 2. Cross-compiling for Windows on Linux or Mac OS X 3. Building on Windows 4. Building on Mac OS X 10. Libraries 11. Glossary 12. Index Introduction OpenSCAD is a software for creating solid 3D CAD objects. It is free software (http://www.gnu.org/philosophy/free-sw.html) and available for GNU/Linux (http://www.gnu.org/) , MS Windows and Apple OS X. Unlike most free software for creating 3D models (such as the well-known application Blender (http://www.blender.org/) ), OpenSCAD does not focus on the artistic aspects of 3D modelling, but instead focuses on the CAD aspects. So it might be the application you are looking for when you are planning to create 3D models of machine parts, but probably is not what you are looking for when you are more interested in creating computer- animated movies. OpenSCAD is not an interactive modeller. -
Polyhedral Mesh Generation and a Treatise on Concave Geometrical Edges
Available online at www.sciencedirect.com ScienceDirect Procedia Engineering 124 ( 2015 ) 174 – 186 24th International Meshing Roundtable (IMR24) Polyhedral Mesh Generation and A Treatise on Concave Geometrical Edges Sang Yong Leea,* aKEPCO International Nuclear Graduate School, 658-91 Haemaji-ro Seosaeng-myeon Ulju-gun, Ulsan 689-882, Republic of Korea Abstract Three methods are investigated to remove the concavity at the boundary edges and/or vertices during polyhedral mesh generation by a dual mesh method. The non-manifold elements insertion method is the first method examined. Concavity can be removed by inserting non-manifold surfaces along the concave edges and using them as an internal boundary before applying Delaunay mesh generation. Conical cell decomposition/bisection is the second method examined. Any concave polyhedral cell is decomposed into polygonal conical cells first, with the polygonal primal edge cut-face as the base and the dual vertex on the boundary as the apex. The bisection of the concave polygonal conical cell along the concave edge is done. Finally the cut-along-concave-edge method is examined. Every concave polyhedral cell is cut along the concave edges. If a cut cell is still concave, then it is cut once more. The first method is very promising but not many mesh generators can handle the non-manifold surfaces especially for complex geometries. The second method is applicable to any concave cell with a rather simple procedure but the decomposed cells are too small compared to neighbor non-decomposed cells. Therefore, it may cause some problems during the numerical analysis application. The cut-along-concave-edge method is the most viable method at this time.