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Computer Graphics1st quarter, 2015

Nara Institute of Science and Technology

April 16, 2015

Welcome back to

Computer Graphics course

Please raise your hand if you are new to this course.

You need course ID.

Write your name on the registration list.

We use “course ID” for grading.

Remember it for future references.

Please check the syllabus.

Sorry, but this course is not archived.

We require you to enroll edX CS184.1x

You can access course material on the web.

(but limited)

(Recap)

Grading

Assignments : 75%

Surveys during the course

Uniform grading independent from the responses.

Graphics programming

Participating Discussions during the class : 25%

Asking questions about computer graphics

“question” is more important than answer.

Answering the question

Welcome to answer the question!

Please tell me your ID when you ask/answer.

(Recap)

Course style

@class

Bring your own device! Participate actively!

We will take surveys for check your understandings

You can do assignment during the class

You can also audit edX course while you wait others

Please bring earphone/headphone if you have

@home

Audit edX course

You can download video/transcript if you want.

Follow up

questions/comments in the previous survey

Feedback to survey- Please tell us if you have concerns

about flipped classroom.

ヘビーそう。

This course seems tough…

課題には早く取り掛かってください．そうすれば必要な支援が受けられます．

Start early!! We can support you if you start early.

授業内で課題が終わらなかった場合，持ち帰ることは可能か？

If I could not finish homework, can I do it at home?

可能です，まずは早く始めてください．課題の提出期日は，課されてから2週間後に提出期限になるようにします．必要があれば翌週授業中に支援を受けてください．

Yes, you can, but Start early!! Each assignment will be due two

weeks after it is out. Please ask us next week if you need supports.

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Start early!!!

https://courses.edx.org/courses/BerkeleyX/CS_184.1x/3T2014/courseware/Unit_3/Homework_3/

Feedback to survey- Please tell us if you have concerns

about flipped classroom.

英語が苦手なので自習の進度が授業に間に合わないのではないかという不安があります。

I’m concerned that I cannot catch up with the course

to audit the online lecture because of English skills.

慣れないスタイルなので正しく活用できるかは心配です。

I’m concerned because I’m not familiar with the style.

こんな形の授業を受けたことないので、まず、うけて見ます。

I’m not familiar with the “flipped classroom.”

オンライン教材は再生が何度もでき，英語の書き起こし文もありますので，英語講義を対面授業でただ聞くだけよりも多くの面で有利です．英語の勉強にもなりますので頑張ってください．

By using online course material, you can repeat the movie and read the transcripts.

It must be easier than to audit face-to-face lecture.

Feedback to survey- Please tell us if you have concerns

about flipped classroom.

情報系出身でないのでコンピュータグラフィックスについて基礎的な部分もわかってないし、英語なのが不安

I’m concerned that I do not know much about computer

graphics. I’m not confident in my English skills as well.

英語がわからないというより、他分野出身なので日本語でも用語がわからない。

I’m not familiar with technical terms even if it is in Japanese.

もちろん，初学者を対象とした講義内容としますので，心配いりません．日本語の質問も歓迎します．分からなければ遠慮なく聞いてください．

Do not worry, this course targets beginners.

Do not hesitate to ask me anything in Japanese.

I will pay efforts to translate it into English.

Feedback to survey- Please tell us in your own words if you

expect/feel/think/doubt something about this

course.

I‘m concerned about following up the course since

my background in CG is not very strong. I hope the

complexity of the course will raise really gradually so

that it’s easier to follow.CGについてあまり詳しくないので付いていけるか不安です．難易度が徐々に上がるようにしてください．

Do not worry, this course targets beginners.

Do not hesitate to ask me anything.初学者を対象としていますので心配ありません．分からなければ遠慮なく聞いてください．

Feedback to survey- Please tell us in your own words if you

expect/feel/think/doubt something about this course.

laptopが重くて持って来れないのですが、必要ならがんばって持ってきます。

My laptop is so heavy…Do I need to bring it?

持ってくるのはassignmentの次の週，支援が必要な時だけで結構です．支援が必要なければ，そのあいだ（授業中に）Online courseの次の単元を（Smartphoneなどで）聴講してもらって構いません．

You can bring your laptop only when you need support

to finish the assignment. If you do not need any support,

you can audit next lecture in edX while waiting for others

during this class.

Feedback to survey- Please tell us in your own words if you

expect/feel/think/doubt something about this course.

it seems interesting. i want to learn how to use

OpenGL properly.

After watching SIGGRAPH's video, I think CG is very

cool and interesting research field.

SIGGRAPHに非常に興味をもちました。 初めて勉強する分野なので、非常に楽しみです。

楽しみにしています

I hope you enjoy this CG course!

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Questions?

Please tell us your ID & name before asking/answering.

Today’s topics

Check your understanding

Computer Graphics Pipeline

Course overview

basic math: Vector/Matrix calculation

Demonstration of homework0

Preview for next topics

Geometrical transforms

Next homework

Homework support

Homework0

Check!

Take a short test from

http://goo.gl/cBLqSm

Questions?

Please tell us your ID & name before asking/answering.

Today’s topics

Check your understanding

Computer Graphics Pipeline

Course overview

basic math: Vector/Matrix calculation

Demonstration of homework0

Preview for next topics

Geometrical transforms

Next homework

Homework support

Homework0

Pipeline

Make a scene as INPUT

Modeling

Describe objects in a scene

Shape / material (color)

Animation

Describe temporal changes of objects

motion

Synthesize an image as OUTPUT

Rendering

Compute light transport

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(Recap)

What is Computer Graphics?

Outputs visual representation via computation

For example,

Static: Pictures / Objects

Dynamic: Movies

Output devices

Printer (static)

Display (dynamic: varying with time)

2D / 3D (spatially)

3D Computer Graphics

Main target of this course:

How to describe 3D scene as INPUT

How to compute 2D image as OUTPUT

Other representations

2D scene -> 2D

3D scene -> 3D printer

Sometimes require “Rasterize” (ラスタライズ)

3D scene -> 3D display

“3D display” mostly use a set of 2D images

ND scene -> 2D : “Visualization” (可視化) research field

How to represent

INPUT/OUTPUT?

vector raster

(x1,y1) - (x2,y2) - (x3,y3) f (x,y) = color

(x1,y1)

(x3,y3)(x2,y2)

Many output devices use

raster description

raster

f (x,y) = color

http://www.canon.com/v-square/movie.html

http://www.eizoglobal.com/products/flexscan/ev3237/index.html

Some devices use vector

description

vector

(x1,y1) - (x2,y2) - (x3,y3)

(x1,y1)

(x3,y3)(x2,y2)

http://fablabkitakagaya.org/

Questions?

Please tell us your ID & name before asking/answering.

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Discuss pros and cons of raster

and vector representation?ラスタ・ベクタ表現の利点・欠点はなんでしょう？

Find neighborhood to discuss

Take 5 min.

A 3D scene is

usually described by vector

Sphere

A set of polygon(many tetragons)

How about raster

as an INPUT?

Digital camera CT Scan

http://vector-conversions.com/vectorizing/raster_vs_vector.html doi>10.1145/1028523.1028571

In 3DCG, we need conversion

from vector to raster

vector raster

(x1,y1)

(x3,y3)(x2,y2)

Rasterizationラスタライズ

vector raster

(x1,y1)

(x3,y3)(x2,y2)

How to do that?

Traceトレース

vector raster

http://tv.adobe.com/watch/visual-design-cs6/new-image-trace/

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Curves

Bézier curve B-Spline curve

http://en.wikipedia.org/wiki/B%C3%A9zier_curve

http://en.wikipedia.org/wiki/B-spline

Questions?

Please tell us your ID & name before asking/answering.

Today’s topics

Check your understanding

Computer Graphics Pipeline

Course overview

basic math: Vector/Matrix calculation

Demonstration of homework0

Preview for next topics

Geometrical transforms

Next homework

Homework support

Homework0

Today’s topics

Check your understanding

Computer Graphics Pipeline

Course overview

basic math: Vector/Matrix calculation

Demonstration of homework0

Preview for next topics

Geometrical transforms

Homework support

Homework0

Recap

Given two column vector 𝒊 =

𝑖𝑥𝑖𝑦𝑖𝑧

and 𝒋 =

𝑗𝑥𝑗𝑦𝑗𝑧

,

express dot product as matrix multiplication.

𝒊 ⋅ 𝒋 = 𝒋⊤𝒊 = 𝑗𝑥 𝑗𝑦 𝑗𝑧

𝑖𝑥𝑖𝑦𝑖𝑧

Recap: dual matrix

Given two column vector 𝒊 =

𝑖𝑥𝑖𝑦𝑖𝑧

and 𝒋 =

𝑗𝑥𝑗𝑦𝑗𝑧

,

express cross product as matrix multiplication.

𝑖 × 𝑗 =

0 −𝑖𝑧 𝑖𝑦𝑖𝑧 0 −𝑖𝑥−𝑖𝑦 𝑖𝑥 0

𝑗𝑥𝑗𝑦𝑗𝑧

Dual matrix

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Recap:

other important ideas

Identity (単位行列)

Inverse (逆行列)

Transpose (転置)

Non-commutative (非可換)

Questions?

Please tell us your ID & name before asking/answering.

Today’s topics

Check your understanding

Computer Graphics Pipeline

Course overview

basic math: Vector/Matrix calculation

Demonstration of homework0

Preview for next topics

Geometrical transforms

Next homework

Homework support

Homework0

Homework0

demonstration

Today’s topics

Check your understanding

Computer Graphics Pipeline

Course overview

basic math: Vector/Matrix calculation

Demonstration of homework0

Preview for next topics

Geometrical transforms

Next homework

Homework support

Homework0

Homework 1

demonstration

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Geometric transform

vector

(x1,y1) - (x2,y2) - (x3,y3)

(x1,y1)

(x3,y3)(x2,y2)

Transform the objects

in the scene

for animation

with respect to the

camera position/direction

Project the scene (3D)

onto the image plane (2D)

of the camera

Questions?

Please tell us your ID & name before asking/answering.

Today’s topics

Check your understanding

Computer Graphics Pipeline

Course overview

basic math: Vector/Matrix calculation

Demonstration of homework0

Preview for next topics

Geometrical transforms

Next homework

Homework support

Homework0

Homework

Unit 1

Lecture 3: Transforms 1

Three movie clips,

about 35 min.

Lecture 4: Transforms 2

Only first movie clips,

about 20 min.

Homework 0

due April 23, 2015.

Print out the results,

submit it in next class.

Include in one page

Your name

Student No.

course ID

screenshot1.png

screenshot2.png

Questions?

Please tell us your ID & name before asking/answering.

Today’s topics

Check your understanding

Computer Graphics Pipeline

Course overview

basic math: Vector/Matrix calculation

Demonstration of homework0

Preview for next topics

Geometrical transforms

Next homework

Homework support

Homework0

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Homework 0 support

Raise your hand for assistance.

If you have no problem,

you can audit next lecture (do homework) now.

Please use earphone/headphone

Unit 1 - Lecture 3 and 4