DOCSLIB.ORG

Effectiveness of Ptex Method in the Field of Texture Mapping and Polygon Topology

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Effectiveness of Ptex Method in the Field of Texture Mapping and Polygon Topology Effectiveness of Ptex method in the field of Texture Mapping and Polygon Topology Andrija Bernik Damir Vusić Robert Geček Department of Multimedia Department of Multimedia Department of Multimedia University North University North University North Varaždin, Croatia, Europe Varaždin, Croatia, Europe Varaždin, Croatia, Europe [email protected] [email protected] [email protected] Abstract — This paper presents several texturing problems that computer resources and mapping automation.[2] The last of occur in complex polygon topology where the model is based on these properties does not agree with Kim et al[9] as far as the tris and ngons. It also shows an experiment and describes the storage efficiency of textures goes. They stated that the Ptex application of the Ptex system for mapping textures onto a 3D Method uses a wasteful packing strategy that increases the model. The topology parameterization using 3D Coat and its storage cost of the textures many times over their original auto-retopology tools are shown as well. A new topology model was tested using a texture checker inside Mudbox and VRay. size. Nevertheless, we have created a 3D model where Additionally, a comparison was made between Mantra and classical UV mapping isn’t efficient and introduced a Ptex VRay rendering systems, where specific difficulties had workflow with rendering specs. occurred when applying Ptex mapping. The aim of this experiment is to present how cache memory directly interferes II. DESIGN AND PARAMETERIZATION OF with texture filtering and rendering speeds. This paper MODEL TOPOLOGY concludes with the advantages and disadvantages observed in relevant literature and through an empirical approach to this A complex model was selected for the elaboration of the technology. textures in order to test the practical flexibility of Ptex (Fig. Keywords — per-face-texturing, ngons, retopology, VRay and 1) and show possible problems that are common in the field Catmullrom filter of CG texturing. This is a part of the replica model of the Koruna Fortress (Fig. 2) which was modelled and analyzed I. INTRODUCTION entirely from scratch by Mario Kotlar (Croteam’s 3D and level artist). Even today’s state-of-the-art graphics hardware, in terms of hardware texture filtering, suffers from several aliasing artifacts that are visible in extreme conditions, such as grazing viewing angles, highly warped texture coordinates, or extreme perspectives.[1] This is one of the reasons that Ptex was initially introduced in 2008.[2] Ptex is an open source product written in C ++ which can easily store a large number of textures in a single file. This texture process is intended for industry branches that require extremely high- resolution (8k+) textures in projects. It converts traditional UV space to a specialized texel system.[3] As a result, only one Ptex file is required per channel per model, since Ptex Fig. 1. Displaying a polygon color quality inside the Meshlab program files have resolution independence across all faces.[4] The result of the above is a texturing system that doesn’t use UV In Fig. 1, the red polygons are those with the lowest maps for texturing or painting a 3D object.[5, 6] Ptex assigns quality, that is, polygons of the greatest elongation. When a separate texture per face, thus skipping the texture unwrap designing the model for 3D printing, it is important to achieve entirely. It must be kept in mind that textures must be power- the optimal number of polygons because this model is not of-two sized (though not necessarily square) and patch intended for sub-divisions but for printing on a 3D printer, so adjacency data must be provided.[6] It uses adjacency in this case it is important that it is non-manifold pointers to access neighboring tiles since it doesn’t pre-filter (waterproof). tile data. These pointers must be dereferenced when filtering on tile boundaries.[7] It is also worth mentioning that the Ptex system is designed for quad-based sub-division surfaces that do not require explicit parameterization.[8] The per-face textures of Ptex are aligned with the shading grids, which always results in horizontal or vertical directions of anisotropy.[1] It ensures four main properties, which are in turn are: photo-realistic quality, generality in terms of geometric model regardless of topology, efficiency in Fig. 2. Photographs of the Koruna fortress (Mali Ston, Dubrovnik, Croatia) 978-1-7281-2544-2/19/$31.00 ©2019 European Union 1 Fig. 3. Texture Checker on the left is shown in Mudbox and on the right in 3D Coat This led to a topology that was expected to be problematic for Ptex. Problems have been shown to be higher than expected. Significant distortions of texture appeared in Mudbox and in 3D Coat as well (Fig. 3). A possible solution to this problem suggested converting elongated trunks into ngons. The result was a complex ngon system. It is known Fig. 5. Examination of poor topology drawing abilities that ngons are quite problematic to work with. Additionally, Mudbox probably does not process them in the correct Fig. 5 shows four divisions that, in turn, represent the manner described in the Ptex standard, as can be seen from following: the distortion form. If Mudbox uses sub-faces in the way it a) A common high resolution. It is noticeable that should, they should look different in the Ptex set-up stage. distortions are still present, However, Mudbox does not process ngons in the way it b) An extremely high resolution of 52 million texels should (via sub-folders), it seems that it divides them into the (roughly a resolution of 7,400 × 7,400 pixel in means of tris system. This could be related to the fact that Mudbox still traditional texture) is localized to 4.4% of the model’s surface uses UV folders to display Ptex in the viewport, which can area, as calculated using Blender, which means that this be concluded from the way in which the polygons containing resolution would require 1.17 billion texels for the whole the minimum level of texels (they have seams) are displayed, model (similar to a traditional texture of 42,000 × 42,000 rather than from the fact that it creates temporary .tif files pixels). However, in practice with Ptex, the amount of while working which otherwise should not be needed. Also, required texels would be less than that, because the texture the fact remains that, during the opening of the .mud model resolution would be localized only in places on the model with Ptex texture, Baking UVs are written in the status line, where it is required. In spite of this, this resolution is still far which is an action that should not normally be needed unless too high for our testing (a mid-end, dual core) machine to UV maps are used.[10] work effectively, c) At extremely high resolution, the texture looks bright, even at considerable magnification, and d) When magnified, it can be seen that the topology still causes a disproportionate distribution of resolution and the occurrence of distortion in certain parts of the model. Fig. 4. Mapping under different projecting angles. From left to right: Maya, From this experiment (Fig. 5), the conclusion is that a Mudbox (frontal projection) and Mudbox (projection at an angle) model with such topology is impossible or almost impossible Another 3D object topology test was to test the results of to texture with the Ptex method using the tools available. It tris, quads and ngons of different shapes. It turned out to be would be far simpler and more optimal to texture this model an important factor in projecting the texture while looking at using traditional UV mapping. The only solution left in this the polygon as straight as possible, i.e. at the correct (90°) case is to repair the model topology (Fig. 6) so that it can be angle (Fig. 4). It can be concluded that the optimal drawing textured by the Ptex method. To avoid manually repairing the of textures in Mudbox is possible only if the model has a model’s topology, which takes a lot of time, automated relatively good topology (that the polygons are as short as methods were investigated. they are elongated) or, if the topology is poor, at a high After many unsuccessful attempts to reparameter the resolution in textile textures is projected at the correct (90°) topology using Meshlab, success was achieved using 3D angle. The next thing to examine is the efficient use of high Coat and its Auto-Retopology tool.[11] The model with the resolution in texels and projection at the correct (90°) angle new topology was opened using Blender and, once a sub- to achieve satisfactory results (Fig. 4). division was made to increase the polygon density, the shrinkwrap modifier was used in order to reposition all the points of the new model in relation to the closest matching points on the surface of the original model. This further sharpened the new model and made it even more similar to the original model.[12] 2 Fig. 6. Comparison of old and new polygon topologies The number of polygons in the process increased from 6,899 to 148,216, which is 21 times more. The number of polygons in this case is not so important, because it will not significantly increase the time required to plot. By comparing the old and new topology, seen in Fig. 6, one can notice the following: • Fig.s a) and b) represent the model before and after the change of topology. There is a visible level of change in Fig. 7. Distribution of the texel’s resolution level at a) minimum resolution x1, b) x4, c) x8 and d) x16 shape between the two models, which in this case is not only insignificant, but is already in its favor, because it is natural III.
Load more

Recommended publications
  • Seamless Texture Mapping of 3D Point Clouds
    Seamless Texture Mapping of 3D Point Clouds Dan Goldberg Mentor: Carl Salvaggio Chester F. Carlson Center for Imaging Science, Rochester Institute of Technology Rochester, NY November 25, 2014 Abstract The two similar, quickly growing fields of computer vision and computer graphics give users the ability to immerse themselves in a realistic computer generated environment by combining the ability create a 3D scene from images and the texture mapping process of computer graphics. The output of a popular computer vision algorithm, structure from motion (obtain a 3D point cloud from images) is incomplete from a computer graphics standpoint. The final product should be a textured mesh. The goal of this project is to make the most aesthetically pleasing output scene. In order to achieve this, auxiliary information from the structure from motion process was used to texture map a meshed 3D structure. 1 Introduction The overall goal of this project is to create a textured 3D computer model from images of an object or scene. This problem combines two different yet similar areas of study. Computer graphics and computer vision are two quickly growing fields that take advantage of the ever-expanding abilities of our computer hardware. Computer vision focuses on a computer capturing and understanding the world. Computer graphics con- centrates on accurately representing and displaying scenes to a human user. In the computer vision field, constructing three-dimensional (3D) data sets from images is becoming more common. Microsoft's Photo- synth (Snavely et al., 2006) is one application which brought attention to the 3D scene reconstruction field. Many structure from motion algorithms are being applied to data sets of images in order to obtain a 3D point cloud (Koenderink and van Doorn, 1991; Mohr et al., 1993; Snavely et al., 2006; Crandall et al., 2011; Weng et al., 2012; Yu and Gallup, 2014; Agisoft, 2014).
    [Show full text]
  • Poseray Handbuch 3.10.3
    Das PoseRay Handbuch 3.10.3 Zusammengestellt von Steely. Angelehnt an die PoseRay Hilfedatei. PoseRay Handbuch V 3.10.3 Seite 1 Yo! Hör genau zu: Dies ist das deutsche Handbuch zu PoseRay, basierend auf dem Helpfile zum Programm. Es ist keine wörtliche Übersetzung, und FlyerX trifft keine Schuld an diesem Dokument (wenn man davon absieht, daß er PoseRay geschrieben hat). Dies ist ein Handbuch, kein Tutorial. Es erklärt nicht, wie man mit Poser tolle Frauen oder mit POV- Ray tolle Bilder macht. Es ist nur eine freie Übersetzung der poseray.html, die PoseRay beiliegt. Ich will mich bemühen, dieses Dokument aktuell zu halten, und es immer dann überarbeiten und erweitern, wenn FlyerX sichtbar etwas am Programm verändert. Das ist zumindest der Plan. Damit keine Verwirrung aufkommt, folgt das Handbuch in seinen Versionsnummern dem Programm. Die jeweils neueste Version findest Du auf meiner Homepage: www.blackdepth.de. Sei dankbar, daß Schwedenmann und Tom33 von www.POVray-forum.de meinen Prolltext auf Fehler gecheckt haben, sonst wäre das Handbuch noch grausiger. POV-Ray, Poser, DAZ, und viele andere Programm- und Firmennamen in diesem Handbuch sind geschützte Warenzeichen oder zumindest wie solche zu behandeln. Daß kein TM dahinter steht, bedeutet nicht, daß der Begriff frei ist. Unser Markenrecht ist krank, bevor Du also mit den Namen und Begriffen dieses Handbuchs rumalberst, mach dich schlau, ob da einer die Kralle drauf hat. Noch was: dieses Handbuch habe ich geschrieben, es ist mein Werk und ich kann damit machen, was ich will. Deshalb bestimme ich, daß es nicht geschützt ist. Es gibt schon genug Copyright- und IPR- Idioten; ich muß nicht jeden Blödsinn nachmachen.
    [Show full text]
  • POV-Ray Reference
    POV-Ray Reference POV-Team for POV-Ray Version 3.6.1 ii Contents 1 Introduction 1 1.1 Notation and Basic Assumptions . 1 1.2 Command-line Options . 2 1.2.1 Animation Options . 3 1.2.2 General Output Options . 6 1.2.3 Display Output Options . 8 1.2.4 File Output Options . 11 1.2.5 Scene Parsing Options . 14 1.2.6 Shell-out to Operating System . 16 1.2.7 Text Output . 20 1.2.8 Tracing Options . 23 2 Scene Description Language 29 2.1 Language Basics . 29 2.1.1 Identifiers and Keywords . 30 2.1.2 Comments . 34 2.1.3 Float Expressions . 35 2.1.4 Vector Expressions . 43 2.1.5 Specifying Colors . 48 2.1.6 User-Defined Functions . 53 2.1.7 Strings . 58 2.1.8 Array Identifiers . 60 2.1.9 Spline Identifiers . 62 2.2 Language Directives . 64 2.2.1 Include Files and the #include Directive . 64 2.2.2 The #declare and #local Directives . 65 2.2.3 File I/O Directives . 68 2.2.4 The #default Directive . 70 2.2.5 The #version Directive . 71 2.2.6 Conditional Directives . 72 2.2.7 User Message Directives . 75 2.2.8 User Defined Macros . 76 3 Scene Settings 81 3.1 Camera . 81 3.1.1 Placing the Camera . 82 3.1.2 Types of Projection . 86 3.1.3 Focal Blur . 88 3.1.4 Camera Ray Perturbation . 89 3.1.5 Camera Identifiers . 89 3.2 Atmospheric Effects .
    [Show full text]
  • Texture Mapping There Are Limits to Geometric Modeling
    Texture Mapping There are limits to geometric modeling http://www.beinteriordecorator.com National Geographic Although modern GPUs can render millions of triangles/sec, that’s not enough sometimes... Use texture mapping to increase realism through detail Rosalee Wolfe This image is just 8 polygons! [Angel and Shreiner] [Angel and No texture With texture Pixar - Toy Story Store 2D images in buffers and lookup pixel reflectances procedural photo Other uses of textures... [Angel and Shreiner] [Angel and Light maps Shadow maps Environment maps Bump maps Opacity maps Animation 99] [Stam Texture mapping in the OpenGL pipeline • Geometry and pixels have separate paths through pipeline • meet in fragment processing - where textures are applied • texture mapping applied at end of pipeline - efficient since relatively few polygons get past clipper uv Mapping Tschmits Wikimedia Commons • 2D texture is parameterized by (u,v) • Assign polygon vertices texture coordinates • Interpolate within polygon Texture Calibration Cylindrical mapping (x,y,z) -> (theta, h) -> (u,v) [Rosalee Wolfe] Spherical Mapping (x,y,z) -> (latitude,longitude) -> (u,v) [Rosalee Wolfe] Box Mapping [Rosalee Wolfe] Parametric Surfaces 32 parametric patches 3D solid textures [Dong et al., 2008] al., et [Dong can map object (x,y,z) directly to texture (u,v,w) Procedural textures Rosalee Wolfe e.g., Perlin noise Triangles Texturing triangles • Store (u,v) at each vertex • interpolate inside triangles using barycentric coordinates Texture Space Object Space v 1, 1 (u,v) = (0.2, 0.8)
    [Show full text]
  • What You Seam Is What You Get: Automatic and Interactive UV Unwrapping
    Online Submission ID: 0270 What you seam is what you get: automatic and interactive UV unwrapping Figure 1: Left: from a meshed model, our system automatically proposes an initial set of seams (black lines) and a valid texture mapping that the user starts with. Right: the user can interactively improve the mapping, by sewing charts and constraining seams (blue lines). As shown in the video, each user interaction is systematically echoed with instant visual feedback. Abstract • (2) Parameterization: each chart in 3-space is put into one to one 2 correspondence with a subset of R ; 3D paint systems opened the door to new texturing tools, directly operating on 3D objects. However, although time and effort was • (3) Packing: the charts are arranged in texture space to minimize devoted to mesh parameterization, UV unwrapping is still known storage requirements. to be a tedious and time-consuming process in Computer Graphics Time and effort was devoted to the problem of mesh parameteriza- production. We think that this is mainly due to the lack of well- tion (see e.g. SIGGRAPH course notes [Hormann et al. 2007] for adapted segmentation method. To make UV unwrapping easier, we an overview). Such mesh parameterization techniques are now well propose a new system, based on three components : • A novel spectral segmentation method that proposes reasonable known and broadly used in the Computer Graphics industry. Re- initial seams to the user; cently, formalizing the relations between deformations and curva- ture lead to both efficient and provably correct methods [Ben-Chen • Several tools to edit and constrain the seams.
    [Show full text]
  • Introduction to POV-Ray
    Introduction to POV-Ray POV-Team for POV-Ray Version 3.6.1 ii Contents 1 Introduction 1 1.1 Program Description . 2 1.2 What is Ray-Tracing? . 2 1.3 What is POV-Ray? . 2 1.4 Features . 3 1.5 The Early History of POV-Ray . 3 1.5.1 The Original Creation Message . 5 1.5.2 The Name . 6 1.5.3 A Historic ’Version History’ . 7 1.6 How Do I Begin? . 8 1.7 Notation and Basic Assumptions . 9 2 Getting Started 11 2.1 Our First Image . 11 2.1.1 Understanding POV-Ray’s Coordinate System . 11 2.1.2 Adding Standard Include Files . 12 2.1.3 Adding a Camera . 13 2.1.4 Describing an Object . 13 2.1.5 Adding Texture to an Object . 14 2.1.6 Defining a Light Source . 14 2.2 Basic Shapes . 15 2.2.1 Box Object . 15 2.2.2 Cone Object . 16 2.2.3 Cylinder Object . 16 2.2.4 Plane Object . 16 2.2.5 Torus Object . 17 2.3 CSG Objects . 22 2.3.1 What is CSG? . 22 2.3.2 CSG Union . 22 2.3.3 CSG Intersection . 23 2.3.4 CSG Difference . 24 2.3.5 CSG Merge . 25 2.3.6 CSG Pitfalls . 26 2.4 The Light Source . 26 2.4.1 The Pointlight Source . 26 2.4.2 The Spotlight Source . 28 2.4.3 The Cylindrical Light Source . 29 2.4.4 The Area Light Source . 29 2.4.5 The Ambient Light Source .
    [Show full text]
  • Developing a Process for Automating UV Mapping and Polygon Reduction
    Linköping University | Department of Computer and Information Science Bachelor’s Thesis | Computer Science Spring Term 2016 | LIU-IDA/LITH-EX-G--16/063—SE Developing a process for automating UV mapping and polygon reduction Julius Willén Tutor, Ivan Ukhov Examinator, Petru Ion Eles Upphovsrätt Detta dokument hålls tillgängligt på Internet – eller dess framtida ersättare – under 25 år från publiceringsdatum under förutsättning att inga extraordinära omständigheter uppstår. Tillgång till dokumentet innebär tillstånd för var och en att läsa, ladda ner, skriva ut enstaka kopior för enskilt bruk och att använda det oförändrat för ickekommersiell forskning och för undervisning. Överföring av upphovsrätten vid en senare tidpunkt kan inte upphäva detta tillstånd. All annan användning av dokumentet kräver upphovsmannens medgivande. För att garantera äktheten, säkerheten och tillgängligheten finns lösningar av teknisk och administrativ art. Upphovsmannens ideella rätt innefattar rätt att bli nämnd som upphovsman i den omfattning som god sed kräver vid användning av dokumentet på ovan beskrivna sätt samt skydd mot att dokumentet ändras eller presenteras i sådan form eller i sådant sammanhang som är kränkande för upphovsmannens litterära eller konstnärliga anseende eller egenart. För ytterligare information om Linköping University Electronic Press se förlagets hemsida http://www.ep.liu.se/. Copyright The publishers will keep this document online on the Internet – or its possible replacement – for a period of 25 years starting from the date of publication barring exceptional circumstances. The online availability of the document implies permanent permission for anyone to read, to download, or to print out single copies for his/hers own use and to use it unchanged for non- commercial research and educational purpose.
    [Show full text]
  • Proposed Workflow for UV Mapping and Texture Painting
    Thesis no: BGD-2016-07 Proposed workflow for UV mapping and texture painting Mostafa Hassan Faculty of Computing Blekinge Institute of Technology SE-371 79 Karlskrona Sweden This thesis is submitted to the Faculty of Computing at Blekinge Institute of Technology in partial fulfillment of the requirements for the degree of Bachelor of Science in Digital Game Development. The thesis is equivalent to 10 weeks of full time studies. Contact Information: Author(s): Mostafa Hassan E-mail: [email protected] University advisor: Francisco Lopez Department of creative technologies Faculty of Computing Internet : www.bth.se Blekinge Institute of Technology Phone : +46 455 38 50 00 SE-371 79 Karlskrona, Sweden Fax : +46 455 38 50 57 i i ABSTRACT Context. There are several workflows for texturing 3D models. 3D models will often have to be constructed and textured before they can be viewed in a game engine. Files would have to be exported and imported in order to view the result. This thesis will look at the usability of having the programs that are used to construct and texture assets connected with each other. In other words, a program would send and receive data in real-time which can be used to avoid the exporting and importing of assets. Objectives. Define a better workflow for texturing models that will be used for games. Compare the usability in terms of speed and the bother of managing asset files. Methods. This work utilizes a comparative experiment were subjects get to test and evaluate two workflows, the traditional workflow which the subjects should already be familiar with, and the prototype system that allows subjects texture painting in real-time.
    [Show full text]
  • Meshes in Games Part 1/2
    3D Video Games 2021-04-22 08: Meshes in Games Part 1/2 3D video games Models for Games Marco Tarini 1 Course Plan lec. 1: Introduction lec. 2: Mathematics for 3D Games lec. 3: Scene Graph ◗ lec. 4: Game 3D Physics + lec. 5: Game Particle Systems ◗ lec. 6: Game 3D Models lec. 7: Game Textures ◗ lec. 8: Game 3D Animations lec. 9: Game 3D Audio lec. 10: Networking for 3D Games lec. 11: Artificial Intelligence for 3D Games lec. 12: Game 3D Rendering Techniques 2 Marco Tarini Università degli studi di Milano 1 3D Video Games 2021-04-22 08: Meshes in Games Part 1/2 Solomons’s key (1986, Temco) on Z80 reminder: during the ’80s – early ‘90s, the principal asset in games consisted in sprites / tilemaps authored by pixel artists ... Metal Slug (1996, Nazca Copr), on Neo Geo (SNK) 3 Triangle Meshes The visual appearance of 3D objects Data structure for modelling 3D objects GPU friendly Resolution = number of faces (Potentially) Adaptive resolution Used in games to represent the visual appearance of 3D objects at least, the ones which can be represented by their surface most solid objects (rigid or not) Mathematically: a piecewise linear surface a bunch of surface samples “vertices” connected by a set of triangular “faces” attached side to side by “edges” 4 Marco Tarini Università degli studi di Milano 2 3D Video Games 2021-04-22 08: Meshes in Games Part 1/2 Triangle Mesh (or simplicial mesh) A set of adjacent triangles faces vertices edges 5 Mesh: data structure A mesh is made of geometry The vertices, each with pos (x,y,z)
    [Show full text]
  • Two Types of UV-Maps RGB Maps: How Are They Obtained?
    3D video gaming - Marco Tarini 2019-05-03 Univ Milano Two types of UV-maps aka: “UV-map” (the standard) NOT injective UV mapping Different zones of the mesh mapped to the same texture region e.g.: with overlapping charts Optimization of texture RAM Can exploit of simmetries / repetitions aka: “Unwrapping” Injective UV mapping or: “Unwrapped UVs” 1 (non empty) point on the texture = or: “1:1 UV-map” 1 point on the mesh or: “Lightmap” UV-map non-overlapping charts! or: Generality / Flexibility “Non-overlapping” UV-map Used for several scopes (e.g. light baking) Different objectives often, both are present: 2 distinct UV maps 2 distinct UV attributes for each vertex Which is the type of the UV-maps shown in prev slides? RGB maps: How are they obtained? Image first, then UV-mapping e.g. Images from photos e.g. tileable images UV-mapper UV-mapping first, then paint 2D paint with 2D app (e.g. photoshop) UV-mapper 2D painter UV-mapping first, then paint 3D paint within 3D modelling software, or: 1. export 2D rendering, 2. paint over with e.g. photoshop, UV-mapper 3D painter 3. reimport images 4. goto 1 Texures part 2 1 3D video gaming - Marco Tarini 2019-05-03 Univ Milano RGB maps: How are they obtained? …or: first Paint 3D on hi-res model, “paint” on vertex attributes e.g. with Z brush… then coarsen build / autobuild final low-poly version then UV-map the low-poly model must be a 1:1 mapping! more then auto-texture about auto build texture this later… Cutout textures example Texels = transparency level (0 or 1) Alpha map RGB map Texures part 2 2 3D video gaming - Marco Tarini 2019-05-03 Univ Milano Cutout textures Texels = transparency level (0 or 1) e.g.: drapes, beard..
    [Show full text]
  • Introduction to POV-Ray
    Introduction to POV-Ray POV-Team for POV-Ray Version 3.6 BETA 2 Contents 1 Introduction 13 1.1 Program Description . 14 1.2 What is Ray-Tracing? . 14 1.3 What is POV-Ray? . 15 1.4 Features . 15 1.5 The Early History of POV-Ray . 16 1.5.1 The Original Creation Message . 18 1.5.2 The Name . 19 1.5.3 A Historic ’Version History’ . 21 1.6 How Do I Begin? . 22 1.7 Notation and Basic Assumptions . 22 2 Getting Started 25 2.1 Our First Image . 25 2.1.1 Understanding POV-Ray’s Coordinate System . 25 2.1.2 Adding Standard Include Files . 27 2.1.3 Adding a Camera . 28 2.1.4 Describing an Object . 28 2.1.5 Adding Texture to an Object . 28 2.1.6 Defining a Light Source . 29 2.2 Basic Shapes . 30 2.2.1 Box Object . 30 2.2.2 Cone Object . 31 2.2.3 Cylinder Object . 31 2.2.4 Plane Object . 31 2.2.5 Torus Object . 32 2.3 CSG Objects . 38 2.3.1 What is CSG? . 38 2.3.2 CSG Union . 38 2.3.3 CSG Intersection . 39 2.3.4 CSG Difference . 40 2.3.5 CSG Merge . 41 2.3.6 CSG Pitfalls . 42 2.4 The Light Source . 42 2.4.1 The Pointlight Source . 43 2.4.2 The Spotlight Source . 44 2.4.3 The Cylindrical Light Source . 45 4 CONTENTS 2.4.4 The Area Light Source . 46 2.4.5 The Ambient Light Source .
    [Show full text]
  • Texture Mapping & Shaders
    Texture Mapping & Shaders © Remedy Enterainment. All rights reserved. This content is excluded from our Creative Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/. MIT EECS 6.837 Computer Graphics MIT EECS 6.837 – Matusik 1 BRDF in Matrix II & III © ACM. All rights reserved. This content is excluded from our Creative Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/. 2 Spatial Variation • All materials seen so far are the same everywhere – In other words, we are assuming the BRDF is independent of the surface point x – No real reason to make that assumption Courtesy of Fredo Durand. Used with permission. © ACM. All rights reserved. This content is excluded © source unknown. All rights reserved. from our Creative Commons license. For more This content is excluded from our Creative information, see http://ocw.mit.edu/help/faq-fair-use/. Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/. 3 Spatial Variation • We will allow BRDF parameters to vary over space – This will give us much more complex surface appearance – e.g. diffuse color kd vary with x – Other parameters/info can vary too: ks, exponent, normal © ACM. All rights reserved. This content is excluded © source unknown. All rights reserved. Courtesy of Fredo Durand. Used with permission. from our Creative Commons license. For more This content is excluded from our Creative information, see http://ocw.mit.edu/help/faq-fair-use/. Commons license. For more information, see http://ocw.mit.edu/help/faq-fair-use/. 4 Two Approaches •From data : texture mapping – read color and other information from 2D images © ACM.
    [Show full text]