Upcoming Deadlines Pick up a clicker find the

Upcoming Deadlines Pick up a clicker, find the right channel, and enter Student ID Fifth Homework (Video Analysis of a Path of Action) Due Tuesday, February 21 st (Next week) 15 points (10 points if late) Sixth Homework (Stop-motion Animation of Falling) Due Tuesday, February 28 th (In two weeks) 20 points (if late, 10 points) Bonus prize of 20 extra points to top three. For full schedule, visit course website: Art. Physics 123. pbworks. com

Extra Credit Opportunity Visit “Renegade Humor” exhibition at the San Jose Museum of Art. Exhibition opens on February 3 rd Turn in proof of your visit (ticket receipt or photos) for 5 points extra credit. For info: www. sjmusart. org

Extra Credit Opportunity Academy Award Nominated Animated Short Films Opens 2/10/2012 at Camera 3 Downtown Turn in your ticket stub for 5 points extra credit.

Extra Credit Opportunity Attend any Cinequest Film Festival event in downtown San Jose. Turn in proof of your attendance (e. g. , access pass, ticket receipt) for 5 points extra credit. For info: www. cinequest. org

Extra Credit Opportunity Attend any GDC (Game Developer Conference) event in San Francisco. Turn in proof of your attendance (e. g. , access pass, ticket receipt) for 10 points extra credit. For info: www. gdconf. com

Extra Credit Opportunity Art of Dreamworks’ Puss in Boots at the Cartoon Art Museum in San Francisco. Turn in proof of your attendance to this exhibition (e. g. , ticket receipt) for 10 points extra credit. For info: cartoonart. org

Homework Assignment #5 In this assignment you’ll again use Tracker software to analyze the motion of a moving object from video reference. First, shoot some reference of yourself doing a running jump. Position your camera so that you're in frame the entire time that you're in the air. Stage the jump to be in profile. Shoot at least 5 takes, even if they are more or less the same.

Homework Assignment #5 Original Video Reference

Homework Assignment #5 Import your video reference into the Tracker software (as in previous homework). Track the center of your waistline or beltline, which is approximately the location of your center of gravity. Marking your position from the time you leave the ground until you’ve landed. After tracking your motion, upload the screen image from Tracker to your blog into a post called "Video analysis of path of action".

Homework Assignment #5 Straight Line Parabolic Path of Action Parabolic Curve

Homework Assignment #5 Finally, rewind your video to the first frame of your jump and from the "File" menu select "Record -> Quicktime Movie". Hit the play button and allow the clip to play until the end of your jump. Next, in the "Capturing Quicktime MOV" window click "Save As" to save the recording.

Homework Assignment #5 Video Reference with Tracking

Homework Assignment #5 Check that your saved Quicktime movie has the track showing the path of action then put both clips (original and with tracking) in your blog post using You. Tube or Vimeo. This assignment is due by 8 am on Tuesday, Feb. 21 st (week from today). 15 points (10 points if late)

Assignment Checklist * Video clip has you running and jumping at least five times. * On one of the jumps you track the center of your body while you're in the air. * Show plots for both horizontal (x) position versus time and vertical (y) position versus time. * Graph of horizontal position versus time is roughly a straight line. * Graph of vertical position versus time is roughly a parabolic arc. * Post your screen shot in a blog entry entitled "Video analysis of path of action". * Post your original reference clip of your five jumps. * Also post a recorded Quicktime movie showing your path of action for one jump.

Activating your Clicker * Turn on your clicker. * Enter the channel number or letter for joining this class. Hit Enter/Send key. * Clicker should read AP 123 S 1 * Type in your student ID; hit Enter/Send. Clicker is now ready to use. Hit any key to wake the clicker from sleep mode.

Survey Question How easy have you found it to use the Tracker software? A) Pretty easy to use B) A little confusing but OK C) Frustrating to use D) Haven’t tried using it yet Note: You score 1 point of credit for answering survey questions, regardless of your answer.

Review Question When a trebuchet throws a stone at what angle should it be released in order to get maximum range? A) Zero degrees (straight) B) 30 degrees C) 45 degrees D) 60 degrees E) 69. 5 degrees

Releasing the Projectile The release mechanism is designed to throw the rock at a 45 degree angle. 45º Release

Maximum Range Maximum range is at a launch angle of 45 degrees (when air resistance is negligible). Height Same initial speeds Range

Review Question The motion graph for a ball drop, going from the apex until the ball just touches the ground, looks like: A) B) C) D)

Motion Graph of a Ball Drop Height D) Frames

Arcs in Animation

Disney’s 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. 1. 2. 3. 4. 5. Squash & Stretch Timing Anticipation Staging Follow Through & Overlapping Action 6. Straight Ahead & Pose-to-Pose Action 7. Slow In and Slow Out 8. Arcs 9. Exaggeration 10. Secondary Action 11. Appeal

Disney’s Principles of Animation In their classic book, Disney Animation – The Illusion Life, already Frank Thomas and We of have discussed Olie Johnston listofa these set of basic several principles of principles for animation, specifically: 1. 2. 3. 4. 5. Squash & Stretch Timing Anticipation Staging Follow Through & Overlapping Action 6. Straight Ahead & Pose-to-Pose Action 7. Slow In and Slow Out 8. Arcs 9. Exaggeration 10. Secondary Action 11. Appeal

Disney’s Principles of Animation In their classic book, Disney Animation – The Illusion of Life, Frank Thomasarcs and Today we will discuss Olie Johnston list athey set of basicto and how relate principles for animation. animated motion. 1. 2. 3. 4. 5. Squash & Stretch Timing Anticipation Staging Follow Through & Overlapping Action 6. Straight Ahead & Pose-to-Pose Action 7. Slow In and Slow Out 8. Arcs 9. Exaggeration 10. Secondary Action 11. Appeal

Arcs of Motion usually follows an arc, which may be simple, like a circle, or very complex and irregular.

Importance of Arcs Disney animation legends Frank Thomas and Olie Johnston write: One of the major problems for the inbetweeners is that it is much more difficult to make a drawing on an arc. Right Drawings made as straight inbetweens completely kill the essence of the action. Wrong

Circular Arcs Circular arcs are common since motion is often around a fixed pivot point, such as a joint.

Speed in Circular Motion Rotational Speed: Revolutions per second Tangential Speed: Total distance per second Same Rotational Speed Different Tangential Speeds

Rolling & Slipping 1 2 3 4 5 6 7 ROLLING Rolling ball turns one revolution when it travels a distance equal to three times its diameter (actually 3. 1416 diameter) 1 2 3 4 5 SLIPPING Slipping and rolling are both uniform in spacing and rotation.

Throwing Arm Sling lengthens the arm at almost no cost in the weight. Doubling the speed quadruples the range! x 2 l tia en d ng ee Ta Sp The longer the throwing arm, the greater the tangential speed so the farther it can throw.

Timing on Circular Arcs A circular arc is a simple path of action but the timing may be complex and textured. in Uniform Slow ow Sl t ou In this golf swing the motion: • Slows out (accelerates) to hit the ball • Uniform after the hit • Slows in as the swing finishes follow-through

Non-Uniform Circular Motion Two common types of motion on circular arcs that have non-uniform timing and spacing are: Exponential Spacing Example: Tipping over Pendulum Spacing Example: Stride in walking

Tipping Over Tipping over is a common example of motion on a circular arc. Two ways to tip over: X Center tipped past point of contact X Center past an edge

Tipping Rotation A brick rotates about a point as it tips; that point is the center of a circular arc. X X Friction tends to keep the brick from sliding until it loses contact with the table.

Exponential Spacing Release 1 1 Constant acceleration (Odd Rule) 3 2 5 3 1 Release 7 4 2 3 Exponential Spacing 4 As the slope of the incline increases, the acceleration itself accelerates.

Rolling off a Tipping Point 1 2 3 4 5 6 7 Peak 8 Slowing out from a tipping point is very slow initially, but then accelerates rapidly.

Video Reference of Tipping Brick http: //www. youtube. com/watch? v=ot. YAYMZ 4 i. Gg

Anticipation & Exponential Spacing Texture of the timing as the brick tips over creates anticipation, which you want at the start of a scene Also notice motion blur near top of brick, which has large tangential speed.

Pendulum Spacing A pendulum’s path of action is also a circular arc but the spacing is very different from the exponential spacing of tipping over.

Spacing & Timing in Swinging A pendulum will slow in and out as it swings back and forth, the same as a ball rolling in a half-pipe. Most of the texture in the timing is at the endpoints; the timing is even in the center.

Pencil Test Example http: //www. youtube. com/watch? v=xuo. Jd. NGxff. U

Motion Graph for Pendulum The motion graph (angle vs. frame) shows that the timing is mostly textured (curves the most) at the apexes. #7 SL O aga W, in SLOW, again Angle #1 FA ST FAST #4 Ball goes fastest around the bottom but the speed is almost constant. SLOW Frame

Uniform Rotation in Perspective The timing for uniform rotation has texture when seen in perspective. Half orbit Quarter orbit Rotation from key #1 to #5 in background takes twice as long as from #6 to #8 in foreground.

Swinging in Perspective Visually the timing has even more texture when the swing occurs in perspective.

Demo: Don’t Flinch Pendulum swings back and forth yet it doesn’t hit your face.

Bowling Ball Pendulum http: //www. youtube. com/watch? v=UNs. D 15 Gj. WWE Click This video clip lets you experience what it’s like to do this demo.

Demo: Interrupted Pendulum An “interrupt” bar changes the radius of the arc for a pendulum. Tangential speed does not increase due to the pendulum whipping around the interrupt bar. Energy is not increased by the interrupt bar so ball swings back to the same spot. Bar

How Does the Brick Fall? Does the brick rotate and then fall down the side of the table? 1 2 XX 3 X No! The brick does not 4 fall this way. X

Video Reference of Tipping Brick http: //www. youtube. com/watch? v=ot. YAYMZ 4 i. Gg

Forces on the Tipping Brick The table pushes on the brick upward and towards the right. Gravity pulls downward Center of the brick shifts down and towards the right. X X If no table…

Pushing Off by the Table X Once it loses contact with the table, only the force of gravity accelerates the brick. X X The table pushes away on the brick, which causes the brick to move away from the table as it falls.

Centrifugal Force Insect inside a can rotating in a circle When we move on an arc, it seems to us as if there is an outward force, pushing us away from the center of the circle. Physicists call this apparent force the centrifugal force. What we see What the insect feels

Class Demo: Bucket Overhead I will put a bucket full of water over my head without getting wet. How? By rotating it fast enough. The water stays in the bucked as if pressed into it by a centrifugal force. You experience centrifugal force on taking a sharp turn Centrifugal Force

Wile E. Coyote & Loop-D-Loop Watch carefully as Wile E. Coyote travels in a circle around a natural arch bridge. From “Beep” (1952) http: //www. youtube. com/watch? v=p 4 Yxd. Xw 9 evc

Wile E. Coyote & Loop-D-Loop If you go fast enough then it is possible to travel upside-down, as Wile E. Coyote does in this scene. True or False? “Beep” (1952)

Wile E. Coyote & Loop-D-Loop True. If his speed is high enough then he stays in contact with the arch, just like the water in the spinning bucket.

Demo: Loop-the-Loop If the speed of the ball is large then not only does it stay on the track, the ball even pushes outward and against the rail. Release Velocity

Demo: Loop-the-Loop Ball could even circle a loop with a gap, if the speed was just right so gravity was equal to the centrifugal force. Release Velocity GAP

Jackass 2 (2006) http: //www. youtube. com/watch? v=36 f. D 7 KSUjkw

Simulated Gravity Centrifugal force could be used to simulate gravity in a space station. With the appropriate rotational speed a person on the outer rim would feel as if they stood on the surface of Earth. Scientifically accurate in the movie 2001: A Space Odyssey (1968) Rotation

2001: A Space Odyssey (1968)

Next Lecture Creating Action Homework 5 th due week from today (Video analysis of Path of Action) Please turn off and return the clickers!