An Introduction To 3d Computer Graphics

An Introduction to 3D Computer Graphics Exploring Photo-Realism with MacRenderMan © Malcolm A. Kesson Version 6.0 PDF 1995 CONTENTS 1 Introduction Interactivity v scripting Illusions and interfaces RenderMan What is a script? Why use scripting? What’s the catch? 2 Getting Started Overview Using a default camera Setting a perspective view Rotating an object Scaling Assembling an object Syntax and the structure of a RIB file 3 Transformations Translation Rotation Scaling Skewing Applying transformations Applying sequences of transformations 4 Shading – the basics Using lights and materials Applying an image to an object Preparing an image for texture mapping Using an image to displace a surface Avoiding rendering errors and improving performance 5 Shaping Up – Library Objects and Polygons Overview – quadrics and polygons RenderMan’s library of quadric surfaces Placing objects in the world Positioning the world relative to the camera Modelling a coffee mug The effects of scaling and translation Reusable geometry Playing with materials – surface shaders wood, carpet and spatter Making a composition the wrong way Making a composition the correct way Another way of grouping objects Summary of methods relating to the grouping of objects A simple polygon model (to be added) 6 An Improved Camera Overview Depth of field Motion blur Field of view Matching a VR camera to a real camera 7 Animation Using FrameUP Animated texture and displacement maps 8 Basic Lighting Overview Defining a light source Types of light sources – descriptions Types of light sources – examples An example script Reference Positioning lights in space 9 Advanced lighting – Casting Shadows Overview An example script The shadow algorithm: how it works An example animation 10 Importing Fragments Overview A sample fragment Importing correctly Importing incorrectly Fragments and objects Restrictions Appendix A – Overview of MacRenderMan Appendix B – RenderMan Quick Reference Appendix C – Shaders Reference Appendix D – Projects Separating Shape from Shading Combining the ‘real’ and the ‘imaginary’ Three Dimensional Icons for a Graphical User Interface Preface These notes are intended to explain the basics of theRenderMan system by providing a series of examples of its use in theMacintosh environment. Although a number of exercises and projects have been included they will only be effective when used by those who wish to explore and experiment with the RenderMan system. I wish to acknowledge the support I received from PIXAR, especially in graciously providing several pre-release versions of their photo-realistic renderer that was being ported to the new RISC based Power-Macintosh computers at the time that I was preparing this booklet for teaching undergraduate students of graphic design the principles of 3D computer graphics. Malcolm Kesson April 1994 Wellington New Zealand In Progress The following sections are incomplete, 5 Shaping Up A sub-section dealing with the way in which RenderMan handles polygons has yet to be added. Several modelling exercises using polygons will also form part of this chapter. 10 Importing Fragments The contents of this chapter are almost complete but some diagrams have yet to be included and the body copy still requires some editing. Additional sections that may be added later include a general explanation about “viewing” and shading as well as the following, 11 Advanced Texture Mapping A chapter dealing with the relationships between cartesian space, texture space and parameter space. Use of texture ‘s’ and ‘t’ parameters to control the texturing of polygons and the use of the command TextureCoordinates to likewise control the texturing of quadric surfaces. 12 Solid Modelling A chapt