Upcoming Deadlines

1
Upcoming Deadlines

• Second Homework (Mini-portfolio)
• Due Wednesday, September 2nd
• 10 points (5 points if late)
• Campus Closed on Labor Day
• Monday, September 7th
• Third Homework (Shooting Reference)
• Due Wednesday, September 9th
• 10 points (5 points if late)
• For full schedule, visit course website
• ArtPhysics123.pbworks.com

Adding one person if interested see me before
class.
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Homework Assignment 2

• Make an entry in your course blog called
  "Mini-Portfolio" and post some images and movies,
  preferably your own work.
• Also tell me a little bit about yourself.
• This assignment is due by 8am on Wednesday,
  September 2nd (in two days).

3
Grading Homework

• The morning that your homework is due Ill visit
  your blog, check that youve done it, assign a
  grade (points), and possibly leave some comments.
• There is a significant penalty for late work so
  finish your assignments on time.
• Plan ahead. Better to post some work early and
  then revise it later, if you have time.

4
Homework Assignment 3

• Video reference is a useful aid in creating
  animation and animators often have to shoot
  reference to suit their needs.
• Your homework assignment is to shoot video
  reference of an object, such as a ball or a water
  bottle, falling straight down from a height of
  about 4 feet.

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Homework Assignment 3

• You have to be the person in the video dropping
  the object so you'll probably need a friend to
  operate the camera.
• Plan your scene so that the object is clearly
  visible on each frame.
• Shoot at least 5 takes, even if they are all more
  or less the same.
• You can record one long clip or several short
  clips.

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Homework Assignment 3

• Many digital cameras have a movie mode and you
  can check out digital camcorders from the SJSUs
  Instructional Resource Center.
• Also find out the frame rate at which your video
  camera records many of them record at 30 frames
  per second instead of the usual 24 frames per
  second used in animation.

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Homework Assignment 3

• Create a post on your course blog entitled "Video
  Reference" and upload your clip(s) into that
  post.
• Keep your clips because you will need them for
  the next homework assignment.
• This assignment is due by 8am on Wednesday,
  September 9th (next week).

8
Extra Credit Opportunity

• Visit the Alexander Calder exhibition at the San
  Jose Museum of Art.
• Exhibition runs through Dec. 13.
• Give me your ticket receipt for five points extra
  credit.

Big Red, 1959
Recommend you visit before Sept. 16 to also catch
the Todd Schorr American Surreal exhibition.
Detail from A Pirates Treasure Dream, 2006
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San Jose Museum of Art

• Hours Tuesday Sunday, 11am - 5pm
• Admission 5.00 for students
• Location 110 South Market St.

You are here
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Activating your Clicker

• Turn on your clicker.
• Enter the number or letter that I give you for
  joining this class. Hit Enter/Send key.
• Clicker should read PHY123SCI2
• Type in your student ID hit Enter/Send.
• Clicker is now ready to use.

Hit any key to wake the clicker from sleep mode.
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Survey Question

• How much time did you spend on the first homework
  (create a blog)
• Less than 30 minutes
• An hour or so
• Several hours
• Did not get it done

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Survey Question

• You have already posted your second homework
  (mini-portfolio).
• True (T) or False (F)

13
Physics ofFalling
14
Ball Drop Animation Exercise
Typically the first example one looks at in
animation is falling motion, such as a falling
ball. In this exercise, the drawing couldnt be
simpler. Its just the same round ball in every
drawing. Nevertheless, animating the ball so
that it moves realistically can still be a
challenge. But the challenge is not in how you
draw the ball but where it is drawn on each frame.
15
Ball Drop in Animation Books
The ball drop is discussed in every major
textbook for animation.
Why is this example considered so important?
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Its all in the timing
An essential element of animation is the timing
and spacing between drawings
Its not important what goes on each frame of
film its the spaces between the frames that are
important. Norman McLaren Oscar winning
animator of Neighbors
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Disneys Principles of Animation
In their classic book, Disney Animation The
Illusion of Life, Frank Thomas and Olie Johnston
list a set of basic principles for animation.
18
Principles of Timing and Spacing
The principles of timing and spacing used to
create a believable ball drop apply to many other
types of motion, even character animation such as
a jumping cat or effects animation such as a
stream of water.
19
Timing Frames, Keys, Clocks

• We use three different ways of measuring time
• Frames (intervals of 1/24th of a second)
• Keys (given number of frames between poses)
• Clocks (actual seconds as measured by a clock)
• For example, you may slug out a scene using a
  stop watch, then convert that into a number of
  key poses, which appear as frames on your dope
  sheet (also called an exposure sheet or X sheet).

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Frames between Keys
Here are the key poses in a jump with the
drawings shot on threes, that is, three frames
per drawing.
Dope Sheet
3
4
2
5
1
IMPORTANT For simplicity, in all our examples
the key poses will always have an equal number of
frames between each key.
21
Uniform Motion
The simplest type of motion is uniform motion a
heavy ball rolling on a table is a good example.
In uniform motion, the velocity is constant so
the spacing from frame to frame is constant.
Larger the spacing, the faster the ball is moving.
22
Uniform Motion Speed
The timing and spacing determine the speed.
This bowling ball is 12 inches in diameter with
two frames per drawing (shooting on twos). What
is the speed of the bowling ball?
The ball rolls about 20 inches per drawing so 10
inches per frame so about 15 m.p.h.
23
Wile E. Coyote on Rocket Skates
Play
Lets estimate his speed in this scene from Beep
Beep
24
Question

• What would you guess is Wiles speed?
• 10 m.p.h.
• 20 m.p.h.
• 40 m.p.h.
• 60 m.p.h.
• 80 m.p.h.
• 100 m.p.h.

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Estimating Wiles Speed
He travels about the length of his ears (say
12-15 inches) per frame so hes only going about
20 m.p.h.
Frame 717
Frame 718
Correction of 20 since movie is 30 fps instead
of 24 fps going 24 m.p.h.
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Uniform Motion in Perspective
Uniform motion may not appear uniform due to
distortion of scale when shown in perspective.
Vanishing Point
Horizon Line
Ball rolling from foreground to background
Distances are equally-spaced, in perspective
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Slowing In (or Easing In)
If an objects motion is not uniform, the object
is either speeding up, slowing down, or changing
direction.
If the speed is decreasing then the spacing
between drawings decreases, which in animation is
called slowing in (or easing in).
Slowing In
A sled slowing by friction is a simple example of
slowing in.
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Slowing Out (or Easing Out)
If the speed is increasing then the spacing
between drawings increases, which in animation is
called slowing out (or easing out).
Slowing Out
Slowing Out
A ball falling downward is another example of
slowing out.
A ball rolling down an incline is an example of
slowing out.
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Spacing Charts
The Animators Survival Kit (and many other
books) presents slowing in and out with spacing
charts next to the animation drawings.
Slowing Out
Slowing In
Pendulum Swing
Spacing Chart
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Slowing In Out in Spacing Charts
Uniform motion (from Animators Survival Kit)
Slowing in out (from Animators Survival Kit)
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Slowing In Out in Character Animation
The importance of slowing in out is that it
occurs so commonly in all types of animated
motion.
(from Animators Survival Kit)
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Disneys Principles of Animation
Slowing in and out is another one of the
principles of animation.
33
Ball Drop Animation Exercise
Lets look at the ball drop in detail, first
looking at the motion as the ball starts to fall
from the apex.
Apex
Play
34
Distance Fallen from an Apex
Distance fallen from the drawing at the highest
point (called the apex) is given by this table.
The formula to compute this table is (Distance
in inches) (Number of Frames) x (Number of
Frames) x (1/3 inch)
35
Distance Fallen and Weight
The distance that an object falls does not depend
on its weight so long as the force of air
resistance is minimal.
A softball and a bowling ball fall together when
released from the same apex.
36
Home Demo Catch a Buck
Take a one dollar bill and have a friend put
their thumb and index fingers near Washingtons
head. At random, let go of the dollar. Can your
friend react fast enough to catch the money?
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Question

• How quickly do you have to react in order to
  catch the dollar?
• 1/24th second
• 1/12th second
• 1/8th second
• 1/4th second
• ½ second
• One second

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Reaction Time to Catch a Buck
Half length of dollar bill is 3 inch so it takes
about 1/8 of a second (0.125 seconds) to fall
this distance. Typical reaction time is 0.20 to
0.25 seconds so most people cannot catch the
dollar.
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Measuring Reaction Time
Distance (inches) Time (sec.) 1
0.07 2 0.10 3 0.12 4
0.14 5 0.16 6 0.17 7
0.19 8 0.20 10 0.23 12
0.25 14 0.27 16 0.29 18
0.30
Release
Catch
40
Slugging and Reaction Time
In planning a scene, you may use a stopwatch to
time it as acted out in live action (called
slugging a scene). Your reaction time is about
a 1/4 second delay so should you subtract that
much from your stopwatch reading?
No, because theres a reaction time delay in
hitting START but also in hitting STOP.
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Planning a Scene (1)

• You want to animate a softball falling straight
  down from a height of four feet. Diameter of a
  baseball is four inches.
• How many total frames will we need to animate?

The table says it takes 12 frames (½ a second)
for the ball to fall four feet. So there will be
13 frames, including the first frame, which is
the release.
?
42
Planning a Scene (2)

• Lets say well shoot on twos and only draw
  every other frame.
• With key 1 being the release, how many drawings
  do you need?

Seven drawings for the 13 frames
?
43
Planning a Scene (3)

• The first key is when the ball is released and
  the second key is two frames later (since were
  shooting on twos).
• About where will the ball be on the second key?

The table tells us that after two frames the ball
to falls 1 1/3 inches (a third of its diameter).
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Next LecturePhysics of Falling IIRevenge of the
Fallen

• By Wednesday
• Complete the 2nd homework
• (Post a mini-portfolio on your blog)

Please return the clickers!