From 3D to 2D: Orthographic and Perspective Projection—Part 1
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CHAPTER 6 PICTORIAL SKETCHING 6-1Four Types of Projections
CHAPTER 6 PICTORIAL SKETCHING 6-1Four Types of Projections Types of Projections 6-2 Axonometric Projection As shown in figure below, axonometric projections are classified as isometric projection (all axes equally foreshortened), dimetric projection (two axes equally shortened), and trimetric projection (all three axes foreshortened differently, requiring different scales for each axis). (cont) Figures below show the contrast between an isometric sketch (i.e., drawing) and an isometric projection. The isometric projection is about 25% larger than the isometric projection, but the pictorial value is obviously the same. When you create isometric sketches, you do not always have to make accurate measurements locating each point in the sketch exactly. Instead, keep your sketch in proportion. Isometric pictorials are great for showing piping layouts and structural designs. Step by Step 6.1. Isometric Sketching 6-4 Normal and Inclined Surfaces in Isometric View Making an isometric sketch of an object having normal surfaces is shown in figure below. Notice that all measurements are made parallel to the main edges of the enclosing box – that is, parallel to the isometric axes. (cont) Making an isometric sketch of an object that has inclined surfaces (and oblique edges) is shown below. Notice that inclined surfaces are located by offset, or coordinate measurements along the isometric lines. For example, distances E and F are used to locate the inclined surface M, and distances A and B are used to locate surface N. 6-5 Oblique Surfaces in Isometric View Oblique surfaces in isometric view may be drawn by finding the intersections of the oblique surfaces with isometric planes. -
An Analytical Introduction to Descriptive Geometry
An analytical introduction to Descriptive Geometry Adrian B. Biran, Technion { Faculty of Mechanical Engineering Ruben Lopez-Pulido, CEHINAV, Polytechnic University of Madrid, Model Basin, and Spanish Association of Naval Architects Avraham Banai Technion { Faculty of Mathematics Prepared for Elsevier (Butterworth-Heinemann), Oxford, UK Samples - August 2005 Contents Preface x 1 Geometric constructions 1 1.1 Introduction . 2 1.2 Drawing instruments . 2 1.3 A few geometric constructions . 2 1.3.1 Drawing parallels . 2 1.3.2 Dividing a segment into two . 2 1.3.3 Bisecting an angle . 2 1.3.4 Raising a perpendicular on a given segment . 2 1.3.5 Drawing a triangle given its three sides . 2 1.4 The intersection of two lines . 2 1.4.1 Introduction . 2 1.4.2 Examples from practice . 2 1.4.3 Situations to avoid . 2 1.5 Manual drawing and computer-aided drawing . 2 i ii CONTENTS 1.6 Exercises . 2 Notations 1 2 Introduction 3 2.1 How we see an object . 3 2.2 Central projection . 4 2.2.1 De¯nition . 4 2.2.2 Properties . 5 2.2.3 Vanishing points . 17 2.2.4 Conclusions . 20 2.3 Parallel projection . 23 2.3.1 De¯nition . 23 2.3.2 A few properties . 24 2.3.3 The concept of scale . 25 2.4 Orthographic projection . 27 2.4.1 De¯nition . 27 2.4.2 The projection of a right angle . 28 2.5 The two-sheet method of Monge . 36 2.6 Summary . 39 2.7 Examples . 43 2.8 Exercises . -
Viewing in 3D
Viewing in 3D Viewing in 3D Foley & Van Dam, Chapter 6 • Transformation Pipeline • Viewing Plane • Viewing Coordinate System • Projections • Orthographic • Perspective OpenGL Transformation Pipeline Viewing Coordinate System Homogeneous coordinates in World System zw world yw ModelViewModelView Matrix Matrix xw Tractor Viewing System Viewer Coordinates System ProjectionProjection Matrix Matrix Clip y Coordinates v Front- xv ClippingClipping Wheel System P0 zv ViewportViewport Transformation Transformation ne pla ing Window Coordinates View Specifying the Viewing Coordinates Specifying the Viewing Coordinates • Viewing Coordinates system, [xv, yv, zv], describes 3D objects with respect to a viewer zw y v P v xv •A viewing plane (projection plane) is set up N P0 zv perpendicular to zv and aligned with (xv,yv) yw xw ne pla ing • In order to specify a viewing plane we have View to specify: •P0=(x0,y0,z0) is the point where a camera is located •a vector N normal to the plane • P is a point to look-at •N=(P-P)/|P -P| is the view-plane normal vector •a viewing-up vector V 0 0 •V=zw is the view up vector, whose projection onto • a point on the viewing plane the view-plane is directed up Viewing Coordinate System Projections V u N z N ; x ; y z u x • Viewing 3D objects on a 2D display requires a v v V u N v v v mapping from 3D to 2D • The transformation M, from world-coordinate into viewing-coordinates is: • A projection is formed by the intersection of certain lines (projectors) with the view plane 1 2 3 ª x v x v x v 0 º ª 1 0 0 x 0 º « » « -
Technical Drawing School of Art, Design and Architecture Sarah Adeel | Nust – Spring 2011 the Ability to ’Document Imagination’
technical drawing school of art, design and architecture sarah adeel | nust – spring 2011 the ability to ’document imagination’. a mean to design reasoning spring 2011 perspective drawings technical drawing - perspective What is perspective drawing? Perspective originally comes from Latin word per meaning “through” and specere which means “to look.” These are combined to mean “to look through” or “to look at.” Intro to technical drawing perspective technical drawing - perspective What is perspective drawing? The “art definition” of perspective specifically describes creating the appearance of distance into our art. With time, the most typical “art definition” of perspective has evolved into “the technique of representing a three-dimensional image on a two-dimensional Intro to technical drawing surface.” perspective technical drawing - perspective What is perspective drawing? Perspective is about establishing “an eye” in art through which the audience sees. By introducing a sense of depth, space and an extension of reality into art is created, enhancing audience’s participation with it. When things appear more real, they become real to the senses. Intro to technical drawing perspective technical drawing - perspective What are the ingredients of perspective drawing? Any form consists of only three basic things: • it has size or amount • it covers distance • it extends in different directions Intro to technical drawing perspective technical drawing - perspective Everyday examples of perspective drawing Photography is an example of perspectives. In photos scenes are captured having depth, height and distance. Intro to technical drawing perspective technical drawing - perspective What is linear perspective drawing? Linear Perspective: Based on the way the human eye sees the world. -
Orthographic and Perspective Projection—Part 1 Drawing As
I N T R O D U C T I O N T O C O M P U T E R G R A P H I C S I N T R O D U C T I O N T O C O M P U T E R G R A P H I C S From 3D to 2D: Orthographic and Perspective Projection—Part 1 •History • Geometrical Constructions 3D Viewing I • Types of Projection • Projection in Computer Graphics Andries van Dam September 15, 2005 3D Viewing I Andries van Dam September 15, 2005 3D Viewing I 1/38 I N T R O D U C T I O N T O C O M P U T E R G R A P H I C S I N T R O D U C T I O N T O C O M P U T E R G R A P H I C S Drawing as Projection Early Examples of Projection • Plan view (orthographic projection) from Mesopotamia, 2150 BC: earliest known technical • Painting based on mythical tale as told by Pliny the drawing in existence Elder: Corinthian man traces shadow of departing lover Carlbom Fig. 1-1 • Greek vases from late 6th century BC show perspective(!) detail from The Invention of Drawing, 1830: Karl Friedrich • Roman architect Vitruvius published specifications of plan / elevation drawings, perspective. Illustrations Schinkle (Mitchell p.1) for these writings have been lost Andries van Dam September 15, 2005 3D Viewing I 2/38 Andries van Dam September 15, 2005 3D Viewing I 3/38 1 I N T R O D U C T I O N T O C O M P U T E R G R A P H I C S I N T R O D U C T I O N T O C O M P U T E R G R A P H I C S Most Striking Features of Linear Early Perspective Perspective • Ways of invoking three dimensional space: shading • || lines converge (in 1, 2, or 3 axes) to vanishing point suggests rounded, volumetric forms; converging lines suggest spatial depth -
Squaring the Circle in Panoramas
Squaring the Circle in Panoramas Lihi Zelnik-Manor1 Gabriele Peters2 Pietro Perona1 1. Department of Electrical Engineering 2. Informatik VII (Graphische Systeme) California Institute of Technology Universitat Dortmund Pasadena, CA 91125, USA Dortmund, Germany http://www.vision.caltech.edu/lihi/SquarePanorama.html Abstract and conveying the vivid visual impression of large panora- mas. Such mosaics are superior to panoramic pictures taken Pictures taken by a rotating camera cover the viewing with conventional fish-eye lenses in many respects: they sphere surrounding the center of rotation. Having a set of may span wider fields of view, they have unlimited reso- images registered and blended on the sphere what is left to lution, they make use of cheaper optics and they are not be done, in order to obtain a flat panorama, is projecting restricted to the projection geometry imposed by the lens. the spherical image onto a picture plane. This step is unfor- The geometry of single view point panoramas has long tunately not obvious – the surface of the sphere may not be been well understood [12, 21]. This has been used for mo- flattened onto a page without some form of distortion. The saicing of video sequences (e.g., [13, 20]) as well as for ob- objective of this paper is discussing the difficulties and op- taining super-resolution images (e.g., [6, 23]). By contrast portunities that are connected to the projection from view- when the point of view changes the mosaic is ‘impossible’ ing sphere to image plane. We first explore a number of al- unless the structure of the scene is very special. -
Cylindrical Anamorphic Images –A Digital Method of Generation
ANDRZEJ ZDZIARSKI, MARCIN JONAK* CYLINDRICAL ANAMORPHIC IMAGES –A DIGITAL METHOD OF GENERATION CYFROWA METODA GENEROWANIA ANAMORFICZNYCH OBRAZÓW WALCOWYCH Abstract The aim of this paper is to present a practical construction for some cylindrical anamorphic images. The method is based on the analytic properties of reflective anamorphic image construction – topics which have been discussed in previous papers. This time, the authors deal with the analytical analysis of a transformation that is applied in order to obtain an anamorphic image, and provide an innovative digital notation of the reflective transformation discussed. The analytical model described here allows us to generate a cylindrical anamorphic image of any object that is represented in the form of a set of parametric equations. Some example anamorphic images together with their counter-images reflected in the surface of a cylindrical mirror will be presented here. The method of construction described enables the development of any design project of an anamorphic image in the urban planning environment and within the interiors of public spaces. Keywords: transformation, anamorphic image, visualization of an anamorphic image, reflective cylinder Streszczenie Niniejszy artykuł przedstawia praktyczną metodę konstruowania obrazów anamorficznych w oparciu o własności analityczne dla anamorf refleksyjnych. Praca jest kontynuacją zagadnień związanych z okre- śleniem geometrycznych zasad powstawania obrazów anamorficznych na bazie obrazu rzeczywistego, na- tomiast prezentuje ona analityczne przekształcenie oraz innowacyjny cyfrowy zapis takich obrazów. Tak więc opracowany model analityczny pozwala generować obrazy anamorficzne dowolnych projektowanych obiektów zapisanych w formie równań parametrycznych. Przykładowe anamorfy zaprezentowano wraz z ich obrazami restytuowanymi za pomocą prototypowego zwierciadła walcowego. Powyższe rozwiązania dają możliwość precyzyjnego projektowania obrazów anamorficznych w zurbanizowanej przestrzeni miej- skiej oraz architektonicznych wnętrzach przestrzeni publicznej. -
CS 4204 Computer Graphics 3D Views and Projection
CS 4204 Computer Graphics 3D views and projection Adapted from notes by Yong Cao 1 Overview of 3D rendering Modeling: * Topic we’ve already discussed • *Define object in local coordinates • *Place object in world coordinates (modeling transformation) Viewing: • Define camera parameters • Find object location in camera coordinates (viewing transformation) Projection: project object to the viewplane Clipping: clip object to the view volume *Viewport transformation *Rasterization: rasterize object Simple teapot demo 3D rendering pipeline Vertices as input Series of operations/transformations to obtain 2D vertices in screen coordinates These can then be rasterized 3D rendering pipeline We’ve already discussed: • Viewport transformation • 3D modeling transformations We’ll talk about remaining topics in reverse order: • 3D clipping (simple extension of 2D clipping) • 3D projection • 3D viewing Clipping: 3D Cohen-Sutherland Use 6-bit outcodes When needed, clip line segment against planes Viewing and Projection Camera Analogy: 1. Set up your tripod and point the camera at the scene (viewing transformation). 2. Arrange the scene to be photographed into the desired composition (modeling transformation). 3. Choose a camera lens or adjust the zoom (projection transformation). 4. Determine how large you want the final photograph to be - for example, you might want it enlarged (viewport transformation). Projection transformations Introduction to Projection Transformations Mapping: f : Rn Rm Projection: n > m Planar Projection: Projection on a plane. -
From 3D to 2D: Orthographic and Perspective Projection—Part 1
INTRODUCTION TO COMPUTER GRAPHICS INTRODUCTION TO COMPUTER GRAPHICS From 3D to 2D: Orthographic and Perspective Projection—Part 1 Drawing as Projection • A painting based on a mythical tale as told by Pliny the Elder: a Corinthian maiden traces the shadow of her departing lover. • History • Geometrical Constructions • Types of Projection • Projection in Computer Graphics detail from The Invention of Drawing, 1830: Karl Friedrich Schinkle (Mitchell p.1) Andries van Dam September 17, 1998 3D Viewing I 1/31 Andries van Dam September 17, 1998 3D Viewing I 2/31 INTRODUCTION TO COMPUTER GRAPHICS INTRODUCTION TO COMPUTER GRAPHICS Early Examples of Projection Early Perspective • Plan from Mesopotamia, 2150BC is earliest • Ways of invoking three dimensional space: known technical drawing in existence. rounded, volumetric forms suggested by shading, spatial depth of room suggested by • Greek vases from late 6th century BC show converging lines. perspective(!) • Not systematic—lines do not converge to a • Vitruvius, a Roman architect published single “vanishing” point. specifications of plan and elevation drawings, and perspective. Illustrations for these writings have been lost. Giotto, Confirmation of the rule of Saint Francis, c.1325 (Kemp p.8) Carlbom Fig. 1-1 Andries van Dam September 17, 1998 3D Viewing I 3/31 Andries van Dam September 17, 1998 3D Viewing I 4/31 INTRODUCTION TO COMPUTER GRAPHICS INTRODUCTION TO COMPUTER GRAPHICS Setting for “Invention” of Brunelleschi Perspective Projection • Invented systematic method of determining perspective projections in early 1400’s. • The Renaissance: new emphasis on Evidence that he created demonstration importance of individual point of view and panels, with specific viewing constraints for interpretation of world, power of complete accuracy of reproduction. -
Perspective Projection
Transform 3D objects on to a 2D plane using projections 2 types of projections Perspective Parallel In parallel projection, coordinate positions are transformed to the view plane along parallel lines. In perspective projection, object position are transformed to the view plane along lines that converge to a point called projection reference point (center of projection) 2 Perspective Projection 3 Parallel Projection 4 PROJECTIONS PARALLEL PERSPECTIVE (parallel projectors) (converging projectors) One point Oblique Orthographic (one principal (projectors perpendicular (projectors not perpendicular to vanishing point) to view plane) view plane) Two point General (Two principal Multiview Axonometric vanishing point) (view plane parallel (view plane not parallel to Cavalier principal planes) to principal planes) Three point (Three principal Cabinet vanishing point) Isometric Dimetric Trimetric 5 Perspective v Parallel • Perspective: – visual effect is similar to human visual system... – has 'perspective foreshortening' • size of object varies inversely with distance from the center of projection. Projection of a distant object are smaller than the projection of objects of the same size that are closer to the projection plane. • Parallel: It preserves relative proportion of object. – less realistic view because of no foreshortening – however, parallel lines remain parallel. 6 Perspective Projections • Characteristics: • Center of Projection (CP) is a finite distance from object • Projectors are rays (i.e., non-parallel) • Vanishing points • Objects appear smaller as distance from CP (eye of observer) increases • Difficult to determine exact size and shape of object • Most realistic, difficult to execute 7 • When a 3D object is projected onto view plane using perspective transformation equations, any set of parallel lines in the object that are not parallel to the projection plane, converge at a vanishing point. -
Bridges Conference Paper
Bridges 2020 Conference Proceedings Dürer Machines Running Back and Forth António Bandeira Araújo Universidade Aberta, Lisbon, Portugal; [email protected] Abstract In this workshop we will use Dürer machines, both physical (made of thread) and virtual (made of lines) to create anamorphic illusions of objects made up of simple boxes, these being the building blocks for more complex illusions. We will consider monocular oblique anamorphosis and then anaglyphic anamorphoses, to be seen with red-blue 3D glasses. Introduction In this workshop we will draw optical illusions – anamorphoses – using simple techniques of orthographic projection derived from descriptive geometry. The main part of this workshop will be adequate for anyone over 15 years of age with an interest in visual illusions, but it is especially useful for teachers of perspective and descriptive geometry. In past editions of Bridges and elsewhere at length [1, 6] I have argued that anamorphosis is a more fundamental concept than perspective, and is in fact the basic concept from which all conical perspectives – both linear and curvilinear – are derived, yet in those past Bridges workshops I have used anamorphosis only implicitly, in the creation of fisheye [4] and equirectangular [3] perspectives . This time we will instead focus on a sequence of constructions of the more traditional anamorphoses: the so-called oblique anamorphoses, that is, plane anamorphoses where the object of interest is drawn at a grazing angle to the projection plane. This sequence of constructions has been taught at Univ. Aberta in Portugal since 2013 in several courses to diverse publics; it is currently part of a course for Ph.D. -
The Baroque in Games: a Case Study of Remediation
San Jose State University SJSU ScholarWorks Master's Theses Master's Theses and Graduate Research Spring 2020 The Baroque in Games: A Case Study of Remediation Stephanie Elaine Thornton San Jose State University Follow this and additional works at: https://scholarworks.sjsu.edu/etd_theses Recommended Citation Thornton, Stephanie Elaine, "The Baroque in Games: A Case Study of Remediation" (2020). Master's Theses. 5113. DOI: https://doi.org/10.31979/etd.n9dx-r265 https://scholarworks.sjsu.edu/etd_theses/5113 This Thesis is brought to you for free and open access by the Master's Theses and Graduate Research at SJSU ScholarWorks. It has been accepted for inclusion in Master's Theses by an authorized administrator of SJSU ScholarWorks. For more information, please contact [email protected]. THE BAROQUE IN GAMES: A CASE STUDY OF REMEDIATION A Thesis Presented to The Faculty of the Department of Art History and Visual Culture San José State University In Partial Fulfillment of the Requirements for the Degree Masters of Arts By Stephanie E. Thornton May 2020 © 2020 Stephanie E. Thornton ALL RIGHTS RESERVED The Designated Thesis Committee Approves the Thesis Titled THE BAROQUE IN GAMES: A CASE STUDY OF REMEDIATION by Stephanie E. Thornton APPROVED FOR THE DEPARTMENT OF ART HISTORY AND VISUAL CULTURE SAN JOSÉ STATE UNIVERSITY May 2020 Dore Bowen, Ph.D. Department of Art History and Visual Culture Anthony Raynsford, Ph.D. Department of Art History and Visual Culture Anne Simonson, Ph.D. Emerita Professor, Department of Art History and Visual Culture Christy Junkerman, Ph. D. Emerita Professor, Department of Art History and Visual Culture ABSTRACT THE BAROQUE IN GAMES: A CASE STUDY OF REMEDIATION by Stephanie E.