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Upcoming Deadlines. Pick up a clicker, find the right channel, and enter Student ID. Homework #9 – Stop-motion character Animation Due Thursday, November 10 th ( Next Thursday ) 20 points (10 points if late); 20 point bonus to top 3 For full schedule, visit course website: - PowerPoint PPT Presentation

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Upcoming DeadlinesHomework #9 Stop-motion character AnimationDue Thursday, November 10th (Next Thursday)20 points (10 points if late); 20 point bonus to top 3

For full schedule, visit course website:ArtPhysics123.pbworks.comPick up a clicker, find the right channel, and enter Student ID1Homework Assignment #9In this assignment you will create a simple stop-motion animation of a moving character. For your character, use a doll or stuffed animal that's easily posed. You may even use an inanimate object, such as a table lamp, as long as you can animate it so that it looks like a character.

2Homework Assignment #9http://www.youtube.com/watch?v=EiEVdTQGGTM

3Homework Assignment #9Your animation should be composed of at least a dozen different images but you can use the same photo in two or more frames to get timing right. Try to make the motion of the character as realistic as possible so that your audience will momentarily forget that it's not actually alive.Inhomework assignment #6you created a stop-motion animation of an inanimate falling object; if you're not happy with how you produced your earlier animation then re-read that assignment for alternative ways of creating stop-motion.4Homework Assignment #9You may work together with one or more classmates to create a single animation for the team. Clearly indicate the work done by each person, for example if different persons animate different characters or different scenes. More is expected from a team effort; an animation created by a three person team should present three times as much work as a solo effort.5Homework Assignment #9Post your animation clip to your blog in an entry entitled "Stop-Motion Character Animation. Assignment due 8am on Thur., November 10th

20 points (if late, 10 points)The top three clips in the class, as selected by a celebrity judge, will receive a bonus of 20 extra points.6Extra Credit OpportunitiesAttend the Star Party this Saturday. Telescope viewing, talks and hands-on activities on Tower Lawn and Science 142Attend the Technology of Animation event, featuring guest speaker Jeffery Katzenberg, at the computer history museum in Mountain View. Registration is at the bottom. http://www.computerhistory.org/events/#technology-animation Attend any event at the San Francisco International Animation Festival (November 10-13).

Present proof of your attendance to any of these (receipt, photos, etc.) for 10 points of extra credit.7Survey QuestionWriting the term paper was:Rather enjoyable Somewhat enjoyableOK Somewhat painfulRather painful

8Survey QuestionFor Dr. Kaufman, do you think reading the term papers was:Rather enjoyable Somewhat enjoyableOK Somewhat painfulRather painful

9Review QuestionAt which position do you exert the least weight on the ground?StrideSquashPassing PositionStretchSame weight at all times

StrideStrideStrideP.P.P.P.

SquashSquashStretchStretch10Force Plate ExperimentsC) Passing Position

Can measure weight shift during walk cycle using force plates.

Body WeightStretchPassingPositionPassingPositionSquashStretch

StrideSquashUpward centrifugal force due to your motion lightens your weight.11Review QuestionCompared with the walking speed of a 6 foot man, the walking speed of a 150 foot giant is

25 times slower5 times slowerAbout the same5 time faster25 times faster

than the man.Jason and the Argonauts

12Stride Time and Stride LengthStride TimeStride LengthSpeedx 2x 4x 2x 3x 9x 3x 4x 16x 4x 5x 25x 5x 10x 100 x 10The giant is x25 taller so each giant stride is x25 longer (in distance).

But the stride time for the giant is x5 more than the mans stride.

So the giants speed is x5 faster than the man.D) 5 times fasterSpeed = ------------ TimeDistance13Jason and the Argonauts (1963)http://www.youtube.com/watch?v=2BaLKYlC07wNotice how the timing of the giants walking gives the sense of his massive scale.

Although the gait his lumbering, the giant easily catches the running men.

14WalksPart II

15Ray HarryhausenRay Harryhausen, the master of stop-motion animation, created the special effects in many films from the 1940s to the 1970s

One of his best scenes in the skeleton battle in Jason and the Argonauts16

Skeleton Battle Scenehttp://www.youtube.com/watch?v=0gKD7qy98-ENotice how the animated skeletons walk (conveniently, we see their pelvis and leg bones).17

Energy and WalkingWere inherently lazy so many actions that we perform unconsciously while walking reduce energy expenditure.So far weve examined walking from the point of view of forces.

An alternative approach is toexamine theenergy expendedin walking.18Home Demo: Silly Walks

Try walking around as John Cleese, who is the Minister of Silly Walks.

You will find that you use much more energy than normal walking.http://www.youtube.com/watch?v=IqhlQfXUk7w

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Energy Budget (Inanimate)Moving objects have an energy budget.For inanimate objects, this budget is:

Kinetic Energy (K) Energy due to their speedPotential Energy (P) Energy due to their heightFriction Loss (F) Energy lost due to friction forcesK = 0P = 100F = 0K = 20P = 70F = 10K = 40P = 40F = 20Total Energy = 10020Demo: Ball RacesMarbles start at equal height and race on these rail tracks (almost no friction).Track B has a long dip in the center.

Winner? A) Ball A; B) Ball B; C) Near perfect tie.Hint: Kinetic energy + Potential energy stays constant.

21Demo: Ball RacesB) Ball B is the winner.

K = 0P = 100F = 0K = 50P = 50F = 0K = 50P = 50F = 0K = 50P = 50F = 0K = 50P = 50F = 0K = 100P = 0F = 0K = 50P = 50F = 0Ball B has a high speed in the center section.22

Energy and Wile E. CoyoteThe energy budget here is wrong because the rock, after rolling down hill, flies back up to a point higher than from where it started!From Going, Going, Goshhttp://www.youtube.com/watch?v=h2j_n0sRXeU23

Energy Budget, BouncingK = 45P = 5F = 0K = 50P = 0F = 0K = 36P = 4F = 10Kinetic EnergyPotential EnergyFriction LossesTotal Energy = 5024

Energy Budget, Sack DropK = 0P = 200F = 0K = 0P = 0F = 200K = ???P = 100F = 5Kinetic EnergyPotential EnergyFriction LossesFlour sack sitting on a shelf starts with potential energy.

After it settles, all the energy is lost to friction forces.

What is the kinetic energy when fallen half-way down?Zero20010095105(Air resistance)

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Energy Budget, Sack DropK = 0P = 200F = 0K = 0P = 0F = 200K = 95P = 100F = 5Kinetic EnergyPotential EnergyFriction LossesD) 95

The total budget (K+P+F) has to equal 200.

If there was no air resistance then the falling speed would be greater and K=100.

With more air resistance, the friction loss would be greater and kinetic energy less.(Air resistance)26

Energy Budget (Animate)Animate objects can increase their energy budget by doing work.

Work Input (W) Energy added by doing work.

K = 0P = 0F = 0W = +0Kinetic EnergyPotential EnergyFriction LossesWork InputK = 100P = 0F = 10W = +110K = 300P = 0F = 20W = +32027Energy Budget in Jumping

K = 0P = 50F = 0W = 0K = 200P = 100F = 50W = +350K = 120P = 175F = 55W = +350K = 90P = 200F = 60W = +350Leg muscles do work as you push off when jumping.Slow down as you rise to apex so kinetic energy (K) goes down.Most of the friction loss is during push but a little loss due to air resistance.28

Energy Budget in WalkingK = 100P = 100F = 60W = +60K = 100P = 100F = 0W = +0Walking takes work due to all the frictional losses.29Simplified Walking ModelPelvis is a double-forked bar with spherical hip joints. Legs are straight bars without knees, ankles, or feet.

Center of gravity rises and falls as an inverted pendulum.

CGCGPassing PositionPassing PositionStrideStridePassing PositionWalking ForwardWe have to do work to raise the CG and much of that energy (30-40%) is lost to friction.30Simplified Walking Model

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Pelvic RotationAs the passing leg swings forward, the hips swing around, rotating about the planted leg.

WithoutRotationWithRotation32Pelvic Rotation

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Pelvic Rotation & Center of GravityPelvic rotation keeps the center of gravity from dropping as far during the stride (keeping step length the same).CGStridePassing PositionPassing PositionPassing PositionStrideCGWalking is more efficient with pelvic rotation.Path of Action ofCG with RotationWithout RotationWalking Forward34

Pelvic ListIn the passing position the pelvis drops slightly on the non-weight bearing side. This motion is called pelvic list.Note that the knee has to bend to lift the foot, otherwise it would drag the ground.35Pelvic List

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Pelvic List & Center of GravityPelvic list keeps the center of gravity from rising as much when the body passes over the weight-bearing leg, keeping the center of gravity on a flatter path of action. CGStridePassing PositionPassing PositionPassing PositionStrideCGWalking is more efficient with pelvic list.Path of Action ofCG without ListWith Pelvic ListWalking Forward37

Knee Flexion of Weighted LegKnee flexes about 15 degrees immediately after heel strike and remains flexed until the center of gravity passes over the weight bearing leg.Walking Forward38Knee Flexion of Weighted Leg

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Knee FlexionKnee flexion keeps the center of gravity from rising as much during the passing position.

Knee flexion also reduces the impact on the body at heel strike.CGStridePassing PositionPassing PositionPassing PositionStrideCGPath of Action of CG without FlexionWith FlexionWalking ForwardWalking is m