CSci 120 - Lecture 20

Multimedia Design

© Morris Firebaugh

I. Introduction

A. Conclude Chapter 10 - Distributing Multimedia Titles

B. Three Approaches to Visual Realism

C. Renderman Example

D. Editing RIB Files

E. Exporting Swivel 3D Files in RIB Format

F. Image Capture with Digital Cameras


II. Conclude Chapter 10 - Distributing Multimedia Titles

Distributing MM Titles Online

Kiosk-based MM


III. Three Approaches to Visual Realism

The three most successful approaches to visual realism are

Ray tracing

Part of the beauty of ray tracing is its extreme simplicity - once you know the necessary background, the whole thing can be summed up in a paragraph. - Andrew Glassner

Figure 10.1 Forward ray tracing. Millions of rays are emitted by the light source L, and one particular ray is shown as reflecting off the larger sphere and striking the center of projection (eye point) through pixel P.

Figure 10.2 Backward ray tracing. Rays originating at the COP pass through each pixel, P, of the image and continue until they strike the nearest surface or exit the view volume. Upon striking the surface the ray's shading is determined by a combination of a shading model applied to the surface plus possible spectral reflection and refraction effects.

Radiosity is the second major rendering algorithm

- Michael Cohen and Donald Greenberg

Renderman -- The third (and practical) solution

RenderMan is the product of a talented team of computer scientists from the Computer Division of Lucasfilm, Ltd. which later became Pixar. The group includes Pat Hanrahan, Ed Catmull, Loren Carpenter, Rob Cook, and Alvy Ray Smith. In 1981 Loren Carpenter wrote REYES whose acronym stands for Renders Everything You Ever Saw. The goal of the designers of REYES was to build an architecture optimized for fast, high-quality rendering of complex, animated scenes. Fast was defined as the capability of rendering a feature-length film in approximately a year; high-quality meant indistinguishable from live-action motion picture photography; and complex meant as visually rich as real scenes, as opposed to the table/lamp/glass sphere scenes typical of previous rendering experiments. REYES was used successfully to produce the Genesis effect in Star Trek II- The Wrath of Khan and served as the foundation for RenderMan. Pixar's RenderMan has subsequently been used to produce the Academy Award winning film, Tin Toy and the water creature in the film, The Abyss.

IV. MacRenderman Examples

Examples of MacRenderman renderings





V. Editing RIB Files

##RenderMan RIB-Structure 1.0
version 3.030
Declare "location" "uniform point"0
Projection "perspective"0
Clipping 1 1000000
Transform [1 0 0 0 0 0 1 0 0 1 0 0 0 0 0 1] 0
ScreenWindow -0.414336 0.414336 -0.31075 0.310750
WorldBegin 0
LightSource "ambientlight" 1 "intensity" [4] 0
LightSource "finite" 2 "location" [-11 0 0]"intensity" [0.4] 0
LightSource "finite" 3 "location" [0 10 10]"intensity" [0.6] 0
Translate -1 10 -1.50
Rotate 20 1 0 00
Rotate -30 0 0 10
Surface "potwood" 0
Geometry "teapot"

Surface "potwood" --> Surface "Blue-Marble"


VI. Exporting Swivel3D Files in RIB Format

Now, let's modify the Shadow scene and render it again


VII. Image Capture with Nikon CoolPix 950


Updated November 5, 2000