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Upcoming DeadlinesSixth Homework (Stop-motion Animation)Due this Thursday, October 6th 20 points (if late, 10 points)Bonus prize of 20 extra points to top three.
Seventh Homework (Outline of First Term Paper)Due next Thursday, October 13th 10 points (5 points if late)
For full schedule, visit course website:ArtPhysics123.pbworks.comPick up a clicker, find the right channel, and enter Student ID1Homework Assignment #6Stop-motion animation of a falling object. * Plan your scene, especially the timing, spacing, path of action, anticipation, etc.* Photograph your object in a sequence of images suitable for combining into an animation.* Create a video clip with at least a dozen unique frames.* Adjust the timing by adding or removing frames; if needed, re-shoot your animation.
2Homework Assignment #6* Post your animation to your blog in an entry entitled "Stop Motion Animation of Falling".* In your posting describe in one paragraph how you created your animation. Due by 8am on Thursday, Oct. 6th20 points (if late, 10 points)Score based on believability and creativity.The top three animation clips in the class will receive a bonus of 20 extra points.
3Homework Assignment #6http://www.youtube.com/watch?v=uOTncsocsUEHere is a good example from last semester. Not only does the falling motion look believable but the action is simple yet entertaining.
4Survey QuestionYou have already started working on your stop-motion animation due this Thursday.True or False
Review QuestionA spool is pulled by a string, wrapped around the center, as shown.The spool will move:PullB) RightA) Left
Force and DirectionLeftObjects always change their velocity in the direction of the applied force.PullPullMotionMotionMotion7Review QuestionBlow hard through a funnel with a ping pong ball in the funnels bowl.Instead of being blown away, the ball is held tightly in the bowl.This is because:PingPongBallBLOWCompression produces low pressureMoving air produces low pressureThe ball spins, producing low pressureNone of the above
Class Demo: Blow the FunnelB) Moving air produces low pressure.This demonstrates the Bernoulli effect, which says that the higher the air speed, the lower the pressure. PingPongBallBLOWLALSquash and Stretch
10In the first part of the course weve covered some of the basics of animation.We now move to more advanced topics, specifically those relevant to character animation.
11Gertie the Dinosaur (1914)This early short Winsor McCay is not the first animated film, it is one of the first to feature a character with a distinct personality.
Running time: 12 minuteshttp://www.youtube.com/watch?v=UY40DHs9vc4
12The Adventures of Prince Achmed (1926)The Adventures of Prince Achmed, by the German animator Lotte Reiniger, is the oldest surviving feature-length (at 65 minutes) animated film.
In this silent movie, Reiniger used silhouette animation, which involves manipulating cutouts (basically two-dimensional stop motion animation).
13The Adventures of Prince Achmed (1926)http://www.youtube.com/watch?v=25SP4ftxklg
14Evolution of Motion PicturesMovies advanced rapidly in the beginning of the last century, adding sound and color.
Birth of a Nation (1915)Gone with the Wind (1939)As realism in movies increased, the stories and the acting had to change as well.15Early CartoonsEarly animations also added sound and color but remained restricted to short films.
Steamboat Willie (1928), the first cartoon with a complete soundtrack.Running Time: 7 minutes
Flowers and Trees (1931), the first cartoon in full Technicolor.Running Time: 8 minutes16Realism BarrierFeature length animated films were not produced because audiences demanded more realistic, complete characters in such movies.Realism Appeal ShortFeature-length
Would you sit through a 90 minute Betty Boop cartoon?17Snow WhiteDisneys Snow White was the first full-length feature film using traditional (cel) animation.
Snow White (1933, 7 min.)
Snow White and the Seven Dwarfs (1937, 83 min.)
18Snow White (1933)http://www.youtube.com/watch?v=IUsp2XxgZTY
19Snow White (1937)http://www.youtube.com/watch?v=nN1BegE3QR0
20Disneys Principles of AnimationFrom life studies, Disney animators discovered that #1 principle that was key to adding realism in character animation was Squash & Stretch.Squash & StretchTimingAnticipationStagingFollow Through & Overlapping Action6. Straight Ahead & Pose-to-Pose Action7.Slow In and Slow Out8.Arcs9.Exaggeration10.Secondary Action11.Appeal
Basic Squash & StretchStretch shows speed due to motion blur.Actual ShapeAs Seen byHuman Eye
Squash shows force, such as on impact.Actual ShapeCartoonBasics of squash and stretch are present in even the simple ball bounce exercise.22Character Animation
From Preston Blairs, Cartoon AnimationBasic squash and stretch are easy to learn from a bouncing ball but their importance is in how squash and stretch appear in the motion of characters.23Luxo Jr.s Squash & StretchAn object need not deform in order to squash and stretch. For instance, a hinged object like Luxo Jr. squashes by folding over on itself, and stretches by extending out fully. John Lasseter
24Luxo Jr. (1986)Luxo Jr. was the first CG film nominated for an Academy Award.http://www.youtube.com/watch?v=PvCWPZfK8pI
25Water Balloon DropWater balloon makes a good animation exercise because it moves like an animate character.
By Mai VuBy Ken Calverthttp://www.youtube.com/watch?v=0yWTJpaoJXIhttp://www.youtube.com/watch?v=ajC1oCZlkQI
26Water Balloon Referencehttp://www.youtube.com/watch?v=XbGVBV3-F48http://www.youtube.com/watch?v=FI-Mq6BDtMQIts always useful to animators to study reference, both live and video.The motion of the water balloon is different with every take, yet has a consistent feel.
27Elements of a Water Balloon DropLets look more carefully at the physics in each element of a water balloon drop.
Initial DropSquashSettleBounce28Part 1: The Initial DropThe initial part of the water balloon drop is similar to other drop tests yet the fluid nature of the balloon adds new elements.
29IncompressibilityMost solids and liquids are almost incompressible; it takes enormous force to change their volume.
Elastic materials may stretch easily but their volume stays constant.30Youngs Modulus (Stiffness)MaterialYoungs Modulus (GPa)Rubber0.01 to 0.1Water7Wood9 to 11Concrete30Steel200Rubber is compressible but water is almost as incompressible as wood!Youngs modulus indicates amount of force required to compress or expand a material.31Demo: Incompressibility of WaterPlace a brick on top of a syringe filled with air.Air compresses (a bit).Place a brick on top of a syringe filled with water.Water doesnt compress.
32Demo: Bed of NailsOne may safely lay or sit on a bed of nails, as long as there are enough nails so that the pressure, measured as force per nail, is small.Weight of 150 pounds is distributed over 300 nails. Force per nail is lb. Need 5 lb per nail to pierce skin.
Pressure depends on weight and on the area supporting that weight.33Pressure in LiquidsPressure in a liquid depends on depth.As with a stack of bricks, weight of whats above determines pressure.
HighMediumLowHighMediumLow34Water Balloon at RestWater pressure pushes on the rubber, stretching it into a flattened shape.HighMediumLowWaterPressureTension of the rubber also affects the shape.35Repose Angle and Contact AngleWater balloon has a repose angle and contact angle that depend on the rubbers stiffness.StiffFlaccidReposeContact
Beads of liquid have similar shapes, depending on surface tension.
MercuryWater36Class Demo: Pressure & WeightA can full of water has holes in the sides through which water comes out.What happens when you drop the can?The can is now in freefall and weightless. Water stops flowing as the can falls since the pressure was due to the waters weight.
37Falling Water BalloonBecause free fall is a weightless state, the water balloon will be roughly spherical as it falls.Slides off and falls
May have some initial vibrations depending on how it is released.
Faucet drip38Air Resistance?Because the water balloon falls faster, the air resistance force on a water balloon is greater than on an air-filled balloon!
However, a few ounces of air resistance force is insignificant for a water balloon weighing several pounds.WaterAirGravityAir Resistance39Part 2: Squash on ImpactThe fluid nature of the balloon makes the squash on impact very pronounced.
Force of Impact for SquashTo understand the force of impact you need to understand momentum and impulse.http://www.youtube.com/watch?v=-p5zoufjOwc41MomentumMomentum of an object is,
(Momentum) = (Mass) X (Velocity)
Examples of objects with large momentums are: Supertanker (large mass) Bullet (large velocity)
42Momentum and ForceTo stop an object with a large momentum requires either:
Large force (stopping the object quickly).Small force applied for a long time.
Notice that changing objects momentum depends on force and time interval.43ImpulseDefine impulse acting on an object as,
(Impulse) = (Force on object) X (Time interval)
Objects have momentum.Impulse acts on an object.44Impulse & MomentumMomentum is related to impulse by,
(Change in momentum) = (Impulse)
When mass stays constant then,
(Mass) X (Change in velocity) =(Force) X (Time interval)