Introduction

CS 658: CG Natural Phenomena

feat. Rendering

Scriptural Thought

DC 88:36-38, 44-47

Scriptural Thought

18 Yea, all things which come of the earth, in the season thereof, are made for the abenefit and the buse of man, both to please the eye and to cgladden the heart;

19 Yea, for afood and for raiment, for taste and for smell, to bstrengthen the body and to enliven the soul.

20 And it pleaseth God that he hath given all these things unto man; for unto this end were they made to be used, with judgment, not to aexcess, neither by extortion.

(DC 59:18-20)

Rendering

• Algorithms and datastructures which create images which look like specified materials under specified lighting conditions from a specified camera.

• Rendering, for real, is unbelievably difficult. • All* CG rendering is some kind of

approximation• Better Approximations more fame.

Rendering

• Rasterization• Ray tracing• Radiosity• Reyes rendering

Ray Tracing

• Basic (see project pages)• More advanced• Distributed• Path tracing.

Rendering Objectives

After this class you should be able to• Discuss the algorithmic strengths and weaknesses

of various approaches to rendering.• Discuss the visual strengths and weaknesses of

images creates by various approaches to rendering.

• Decide which approach to rendering is most appropriate in a given situation.

• Implement distributed ray tracing.

Part 2: Modeling of Nature

• Stuff you find outside• Not manmade• Powerful images for telling stories

David Iliff, Hopetoun Falls, from Wikipedia. Abubakr Hussain, Mohammed-Hayat Ashrafi, Maaz Farooq, Farmaan Akhtar, Mohammed Shah, “Loch Lomond, from Wikipedia (License)

Computer Generated Nature

• Algorithmic forgeries of nature.• Synthetic images.• Synthetic animations.• Used in film and games• Also used to visualize stuff. • Should result in either… – An image not distinguishable from actual photograph, or – Whatever the director wants.

• We are not there yet.

Philip Ronan, Fractal plant, from Wikipedia.

Examples

• Pixar Shorts: watch the evolution– In the beginning: Adventures of Andre and Wally B. – Rain: Red’s Dream– Getting better: Jerry’s Game– Little of everything: Boundin’– Big tree, tricky light: Lifted

This Class

Algorithms and data structures for creating images and animations which include natural phenomena.

Jens Bischoff Joel Durier (Phylloxera). You can visit his site here.

Objectives

After CS 658 you should be able to• Recall the classic algorithms• See the algorithm in a process• Appreciate the role of nature in storytelling• Have a deeper appreciation for what you see

in nature.

Image created by Volker Harun. You can visit his site here.

Stuff you’ll do

• Implement some algorithms • Do a semester project of your* choosing • Discuss important or recent papers • Download and try various tools

Stewart McSherry using Xfrog

Small Projects

• Implement the classic algorithms– Ray tracing upto distributed ray tracing– L-systems– midpoint displacement

http://en.wikipedia.org/wiki/Image:Fractal_weeds.jpg

Make-an-image Projects

• Download a tool, use it to make an image.• Post the image to the gallery on the class

homepage.

Semester project

• Work alone or in a group of 2.• Pick projects on 1/15.• I want to be involved in the projects and I

want them to be interesting. • I made a list of projects. • You get to pick from this list (on 1/15).• Picking algorithm is in the syllabus.• Projects are on the webpage

Parts of the Project

• Literature review– 2 most significant papers– 5 related paper (2 are the most significant)

• Proposal• Progress reports• Demo• Final report

Discussing papers

• We will discuss…– Things you didn’t understand.– Things you thought were cool.– What’s next after this paper?