Physics of Animation (Art/Physics 123 @ SJSU): 2010

If you are reading this blog then you're probably enrolled in Physics of Animation (Art / Physics 123) at San Jose State. I will be using this blog primarily to post examples to help you with your homework assignments, which you'll be posting on blogs of your own.

The earlier posts on this blog are from the Fall 2009 and Spring 2010 semesters; the course this semester will be similar but not exactly the same. Nevertheless, the postings from previous semesters will give you a general idea of the kinds of assignments you'll be doing. You will also find it useful to look at the blogs of students who took the course in the past two semesters. All the information and links you'll need about the course is found on the course website, http://artphysics123.pbworks.com/.

Your first homework assignment for the course will be to set up a blog of your own, which you'll use to post homework assignments and term papers. You'll find more info on this first homework assignment here.

See you in class! Alej Garcia

Sunday, May 9, 2010

Creating Stereoscopic 3D Images

The photo below is a Green/Magenta 3D anaglyph image of my (messy) office.

Here is the Red/Cyan version:

For the image below the photos were shifted to align the phone, which puts it at screen depth.

And for the image below the photos were shifted to put the bookshelf on the far left of the screen at screen depth (which essentially puts everything else inside the screen).

Last semester this assignment was different, in fact it was optional for extra credit. Here are some examples from last semester:

http://ryancanimation.blogspot.com/2009/12/stereo-3d-images-extra-credit.html
http://stevendalcanto.blogspot.com/2009/12/stereo-3d-photo.html
http://kathleen-obrien1300.blogspot.com/2009/12/stereo-3d-images.html
http://yolandaphysic123.blogspot.com/2009/12/stereo-3d-photo.html

Be sure to read the assignment carefully and include all the required photos. In fact, I recommend that you shoot five times more photos than you think you'll need because most photos do not make an effective 3D image. Furthermore, it's not uncommon to make errors, such as rotating the camera when repositioning it. Finally, be creative with your images and make them varied and interesting.

Thursday, April 29, 2010

Lighting a Scene in Maya

One-Point Lighting (Single key light on the left casting strong shadows).

Two-Point Lighting (Additional fill light to soften the dark shadows)

Three-Point Lighting (Rim light behind the letters to accentuate the edges).

The images above were created by Candace Downey.

Here are some of the better ones from last semester:
http://stevendalcanto.blogspot.com/2009/12/lighting-scene-in-maya.html
http://christopherheckey.blogspot.com/2009/12/lighting-scene-in-maya.html
http://miyukianimationphysics123.blogspot.com/2009/11/lighting-scene-in-maya.html
http://ericart123.blogspot.com/2009/12/three-point-lighting-two-point-lighting.html
http://lain-yee.blogspot.com/2009/12/maya-initials-scene-and-lighting.html

Wednesday, April 21, 2010

Building a Scene in Maya

Above is an example for this assignment (created by Candace Downing, so the letters are "c" and "d"). Your letters may be upper-case and/or lower-case; they may be a single object or several objects put together. Your scene can be fancier that this example but do not include any extraneous elements other than the floor, the wall in the background, and the two letters in the foreground.

Here is some of the best work from Fall 2009 semester:
http://christopherheckey.blogspot.com/2009/11/building-scene-in-maya.html
http://astrosplayhouse.blogspot.com/2009/11/building-scene-in-maya.html
http://physics123alanpasman.blogspot.com/2009/11/building-scene-in-maya.html
http://elizabeth-medina.blogspot.com/2009/11/building-scene-in-maya.html
http://samcriner.blogspot.com/2009/11/building-scene-in-maya.html
http://ryancanimation.blogspot.com/2009/11/building-scene-in-maya.html

Thursday, April 8, 2010

Science Fact or Cinematic Fiction

Here are links to three term papers from Fall 2009 semester that are examples for the second term paper assignment:

http://physicsofthedead.blogspot.com/2009/11/10-science-fact-or-cinematic-fiction-of.html

http://miyukianimationphysics123.blogspot.com/2009/11/second-term-paper.html

http://tirasuwan-artphysics123.blogspot.com/2009/11/science-fact-or-cenematic-fiction.html

Saturday, March 20, 2010

Stop-Motion Character Animation

Here is an example of a stop-motion animation of a walk cycle done by Corey Tom.

The top three character animations last semester are these:

http://miyukianimationphysics123.blogspot.com/2009/10/stop-motion-animation_23.html

http://samdebey.blogspot.com/2009/10/stop-motion-animation.html

http://clamphysics123.blogspot.com/2009/10/stop-motion-animation.html

Note that the last one was a team effort; if you work as part of a team then be sure to include a shot breakdown, saying who did what.

Wednesday, March 17, 2010

Reverse Video Reference of Walking

Here are the top reverse video reference clips from last semester:

Clip A: Original Animation / Reverse Video Reference

Clip B: Original Animation / Reverse Video Reference

Clip C: Original Animation / Reverse Video Reference

Clip D: Original Animation / Reverse Video Reference

Clip E: Original Animation / Reverse Video Reference

Note that this semester the animation clips are different from last semester! For details on this semester's assignment, go here.

Sunday, March 7, 2010

More Examples for the First Term Paper

Here are some good examples of term papers from last semester:

http://christybecker.blogspot.com/2009/10/exp1.html

http://michellej-artphys.blogspot.com/2009/10/1st-term-paper-superman.html

http://ericart123.blogspot.com/2009/10/matrix-movie-directed-by-wachowski.html

http://samdebey.blogspot.com/2009/10/toy-story-analysis.html

http://linford-artphysics123.blogspot.com/2009/10/laws-of-physics-in-animation-universe.html

Wednesday, March 3, 2010

First Term Paper

Below is an sample for the first term paper assignment; the paper was written by Corey Tom, with a few editorial changes by myself. Note that the paper does not exactly follow the outline (see previous post) but is mostly faithful to it. If you decide to deviate significantly from your outline, that's OK but write me a short note at the end of your term paper describing the differences.

http://en.wikipedia.org/wiki/File:Tiposter.jpg

IncrediPhysics – Physics in The Incredibles movie

Pixar’s animated feature film The Incredibles shows us a world very much like our own, but with one main difference: the existence of superheroes (and super villains). This world, for the most part, operates by the same laws of physics as our own. There are but a few exceptions where these rules are bent or broken for the sake of the world of these super humans. These include the heroes’ abilities and even their clothes.

[To play movie trailer, go to: http://www.imdb.com/rg/VIDEO_PLAY/LINK//video/screenplay/vi2311127321/].

This paper discusses how the world in The Incredibles works, focusing specifically on the physics of that animated world. The laws of gravity in the movie are still very much like our own. The first example is at the beginning of the movie, when Mr. Incredible thwarts a suicide jumper’s attempt to kill himself by jumping off a tall building. As an estimate, the stories on the building look to be at least 30 feet tall. Mr. Sansweet, the jumper, falls about 15 stories or more in a time of about 6 seconds before he’s intercepted by Mr. Incredible. That means in 6 seconds he fell about 450 feet. According to the equation (Distance in inches) = (1/3 inch) x (Number of Frames) x (Number of Frames) , we get (1/3in.) x (24 x 6) * x (24 x 6) = 6912 inches which means he should fall 576 feet in that time. Given that he may have jumped upward off of the ledge instead of dropping straight off, and some drag created by his clothing and by falling in a horizontal pose instead of in a nosedive, a lesser distance of 450 feet is reasonable.

There are plenty of other examples of objects falling over a smaller distance in a believable manner according to the usual laws of gravity, such as the cup of pencils on Bob’s desk after being berated by his boss, Mr. Huph, which falls comparably to a brick drop animation pencil test. There’s also the scene where Mr. Incredible realizes he has Syndrome’s remote and subsequently gets smashed by the robot. The remote gets thrown in the air, then it drops and bounces very similar to the timing in a ball drop. These examples and countless others within the film help create a consistent and believable world with gravitational forces very similar to our own.

Another example of falling occurs during the big finale when Syndrome’s plane explodes and falls to the ground with perfect dramatic timing, hitting the ground immediately after Elastigirl lands with Jack Jack. This example could be compared to a similar occurrence earlier in the movie, when Elastigirl’s plane gets destroyed by missiles. This is one of the few times where the law of gravity or the properties of air resistance seem to have been warped in this movie. The plane explodes, sending debris and our three heroes plummeting toward the ocean. However, it should be noted that the three of them seem to fall faster than the debris. This is reasonable at the beginning of the scene as Elastigirl is still in a ball, providing the least air resistance, and much of the debris is more flat, providing much more surface area for drag. However, as soon as she unravels and they continue falling, the three characters still fall faster than the debris. In addition, when Elastigirl grabs them out of the air and unfurls herself into a parachute, we are looking up at them and yet we don’t see any sign of debris or the explosion behind them (which was most likely an art decision so that the scene wasn’t too cluttered). We don’t see any falling debris until they are just landing in the water, the debris falling far away in the background. Again, the debris is falling slower than them, even with Elastigirl as a parachute.

The characters begin talking and a couple of seconds later what appears to be the nose of the plane finally plummets (nose first) into the ocean right where they were. Given that Elastigirl severely slowed their descent as a parachute and the nose of the plane is a very aerodynamic piece, one would expect the plane’s nose to have hit the water much sooner, if not before, the characters landed in the ocean. The reason for this discrepancy with the standard laws of physics is to achieve dramatic effect. The movie’s heroes have just survived a mid-air explosion and the nose nearly crushing them after they’ve safely landed in the water is the button to the sequence.

Another notable difference between the world of The Incredibles and our own is the super suit. Designed by Edna Mode, these thin fabric suits are made to protect the superhero from anything a villain might throw at them, from bullets to a raging inferno to powerful explosions. This is beyond any cloth that exists in our world, the only possible equivalent materials at our disposal would be dense body armor (which would only protect against the bullets) or a reinforced bunker (which could still be destroyed by bombs/missiles). But even Mr. Incredible’s old super suit gets torn by an initial attack by the Omnidroid, which seems to say that the technology behind these super suits gets outdated by newer weapons. Therefore, Mode designs a new suit for Mr. Incredible and his family (despite Incredible’s request for a simple patch up), which, as she shows to Elastigirl, is completely bulletproof, nearly indestructible (as it gets hit with two missiles), and able to withstand temperatures of over one-thousand degrees among other features (such as, comically, being machine-washable). Again, the technology behind these suits is beyond what we have, but we accept it because a super hero needs a suit that can withstand the trials of their battles.

This could even be compared to other superhero movies, cartoons, or comics. Two well-known heroes, Batman and Superman, receive damage to their suits all the time. A good indicator of how much they’re actually getting beat up seems to be how torn up their suit is as well, otherwise we would only see a beat up face (or in Batman’s case, a mouth). Referring back to the Incredibles, even if this cloth is super strong and nearly impervious, there’s still the human factor. Even though these people are super humans, they’re still not invincible. Mr. Incredible gets cut by the Omnidroid, Violet gets knocked out by the later version of the robot, and Elastigirl gets temporarily knocked unconscious by the missile explosion.

They can still get injured just as we can still be injured by a bullet even if wearing a bulletproof vest. The vest does well to prevent any kind of fatal injury by preventing the bullet from penetrating the body. Nevertheless, the bullet’s momentum has to be stopped by the suit and the shorter the distance in which the bullet is stopped, the greater the force. This is the same principle that tells us that when an object hits the ground a slow squash on impact exerts a smaller force than a sudden, quick halt. So even if the clothing is impenetrable, a deadly projectile stopped in a short distance exerts a large force on the character, leading to bruising, broken ribs, or even greater internal bodily damage. A “superhero” may be able to take a bigger beating than your average human (otherwise they wouldn’t be super!) and therefore more resistant to damage to their person. Despite this gap between our world and theirs, we accept that these suits can provide the protection they do because it’s a movie and it’s about superheroes.

The final point to discuss is the various superheroes’ special powers. They range from being able to bend the laws of physics to actually defying them. One of the most obvious is the ability to fly. None of the main super heroes in the movie can fly (though baby Jack Jack levitates), but in brief flashbacks several minor characters were shown to be able to fly, much like the familiar Superman. The characters have no propulsion except for the initial push off from the ground. Given the large amount of energy required to lift a person’s weight to a great height, using only the push off the ground requires that force to be extremely large, resulting in a violent acceleration when taking off.

Once in the air these flying superheros seem to control speed by giving a little more intense look or thrusting their arms forward, and they can control direction and altitude by just thinking or actually tilting themselves to where they want to go. The fact is, though, that they purely defy gravity, and it’s mostly due to the eternal human desire to be able to fly like a bird. The closest we can come to this in the real world is wearing a special jump suit, called a wingsuit, which basically turns the wearer into a flying squirrel (http://www.youtube.com/watch?v=JHlOvhlKPvs) or strapping small jets to our body for propulsion (http://www.youtube.com/watch?v=EP3JIrJMrrY).

Other superhero powers are more grounded in reality, but then pushed beyond human limitation. Super strength, speed, and stretchiness, for example: humans have a very limited ability for each of these (stretchiness would be more like an extension of flexibility), some are able to push themselves farther than other people such as bodybuilders for strength, track sprinters for speed, and gymnastics or practitioners of yoga for flexibility. Many other superhero powers are grounded in reality, whether pulling from science or nature. Violet’s invisibility power, for example, can be compared to animal’s camouflage in nature. There are octopi, cuttlefish, chameleons, and many other species of animals that can actually change pigments in their skin to blend in flawlessly with their surroundings. There has also been recent developments at UC Berkeley in making “a metamaterial which has a negative refraction index….it bends light around the object. It currently works only on microwave frequencies but is expected to work on the visible spectrum as the materials are made smaller.”

Violet’s other power is to create a force field, something scientists are working with to protect space travelers and satellites. This generally involves the use of plasma rather than generating some kind of energy field out of thin air as is the case in most fiction. In “The Incredibles”, with the exception of flight without propulsion, superhero abilities are founded in a human ability that is pushed way beyond its current limits.

Pixar created a world similar to our own in “The Incredibles”, with the slight difference of superheroes and villains. They stayed true to their world in a consistent portrayal of the laws of physics in their world with some exceptions where the rules were broken to give better effect to the scene. The animators gave us a believable universe where most ideas are grounded in our reality and the rest pulled from what we’re used to in superhero stories. In the end, we are left satisfied with having watched an Incredible movie.

Outline of the First Term Paper

Below is a sample outline for the first term paper (see post above). This outline was written by Corey Tom, with some editorial changes by myself. Note that the term paper does not follow the outline exactly but does not deviate from is wildly.

Physics in "The Incredibles"

I. Introduction – Superheroes in a human world

a. Laws of gravity are normal by our standard
b. Incredibly strong cloth
c. Superheroes are the only ones able to bend the laws of gravity/physics
d. Thesis statement

II. Laws of gravity - If you can’t fly or float, you still fall at about a “normal” rate

a. Suicide jumper
b. Falling out of the plane

i. law broken for effect – the characters fall to the water way before the plane

c. objects falling

i. cup of pencils
ii. the robot
iii. Syndrome’s plane

III. Incredibly strong cloth

a. Original super suit – designed to be strong, but outdated
b. New super suit – refer to E’s descriptions
c. The cloth is strong, but there’s still the (super)human factor

i. Elastigirl is initially unconscious from missile explosions
ii. Superhero takes a beating, but cloth survives – compare to armor for us
iii. Invisicloth?

IV. Superheroes vs. gravity and physics

a. Flight/levitation

i. Super jump?
ii. Actual repulsion of gravity?

b. Strength, speed, stretchiness

i. Superhero bodies able to do things way beyond human limits

c. Invisibility and creating force fields

i. Force fields - Some superheroes (Violet) able to do what takes several high powered machines to attempt for us
ii. Active camouflage – adjusting colors based on surroundings
iii. Refer to animal world – chameleons, cuttlefish, octopi, etc

V. Conclusion

a. Summation of points
b. Restate thesis

Thursday, February 25, 2010

Stop-Motion Animation of Falling

Below is a stop-motion animation of a ball bounce cycle created by Corey Tom.

This animation was created using a Logitech Webcam connected to a PC running SAM Animation. The ball was placed at various positions on the floor; Corey says that it was helpful to plan out the positions by making marks on the floor, just off-camera. There are only a handful of separate images; the sequence is repeated 10 times for 10 bounces.

This ball bounce cycle is very simple so you're encouraged to create something more interesting; you'll be graded on both the believability of the physical motion and on the creativity of your work. For inspiration, watch any of the episodes of Wallace and Gromit, for example:
http://www.youtube.com/watch?v=dy9QeosTh7w

Wednesday, February 17, 2010

Video Analysis of Path of Action

Here is the original video reference, which has several jumps on the same clip. Most of the jumps are kind of wimpy but the first one is pretty good.

Below is the image showing the path of action for the jump as well as the graphs of the horizontal versus time and the vertical position versus time.

Notice that the graph of horizontal position is a straight line, which indicates constant speed in the horizontal direction. The graph of the vertical position is a parabolic arc, similar to the graph in the previous homework (track of a falling object), except that in this case you first rise and then fall back down. But notice how the rising motion is symmetric with the falling motion.

Finally, here is the video clip with tracking:

Here are some further examples from last semester:
http://terrychiem123.blogspot.com/2009/09/video-analysis-of-path-of-action.html
http://physicsofthedead.blogspot.com/2009/09/4-homework-5-video-analysis-of-path-of.html
http://kathleen-obrien1300.blogspot.com/2009/09/video-analysis-of-path-of-action.html
http://annaime.blogspot.com/2009/09/video-analysis-of-path-of-action.html

Wednesday, February 10, 2010

Tracker video analysis of falling

The image below shows the track of the falling ball, as obtained using the Tracker software.

The plot on the upper left is the horizontal position versus time. The graph should be a flat line because the ball does not move left-to-right but it's hard to mark the exact position so the graph shows some random variation.

The lower plot of the vertical position versus time is more interesting. Notice that this plot is a parabolic arc. There are about 16 frames from apex to impact and the 8th frame (half way down in time) is about a quarter of the distance from the apex to the ground. The frame rate in this clip is 30 fps so it takes just over a half second for the center of the ball to fall a height of about five feet (Corey Tom, who is dropping the ball, is 5 foot 9 inches tall).

Here are some examples from last semester:

http://samcriner.blogspot.com/2009/09/tracker-video-analysis-of-falling.html

http://edwardsartphysics123.blogspot.com/2009/09/tracker-video-analysis-of-falling.html

http://daytonalhazenskuse.blogspot.com/2009/09/tracker-video-analysis.html

http://kimknollanimationphysics.blogspot.com/2009/09/tracker-video-analysis-of-falling.html

Saturday, February 6, 2010

Video Reference

Here is the video reference for a falling object (as dropped by SJSU's own Corey Tom). This reference was shot using a Sony HD digital camcorder and recorded at 30 frames per second.

Thursday, January 28, 2010

Mini-Portfolio

Here are some examples of the "Mini-Portfolio" assignment (Homework #2):

http://christybecker.blogspot.com/2009/09/mini-portfolio.html
http://ryancanimation.blogspot.com/2009_08_01_archive.html
http://clamphysics123.blogspot.com/2009_08_01_archive.html
http://miyukianimationphysics123.blogspot.com/2009/08/mini-portfolio.html
http://artphysics123.blogspot.com/2009_05_31_archive.html

Wednesday, January 6, 2010

Spring Semester 2010

If you are reading this blog then you're probably enrolled in Physics of Animation (Art / Physics 123). This blog is primarily used to post examples to help you with your homework assignments, which you'll be posting on blogs of your own. Most of the information you'll need about the course is found on the course website, http://artphysics123.pbworks.com/.

Your first homework assignment for the course will be to set up a blog of your own, which you'll use to post homework assignments and term papers. You'll find more info on this first homework assignment here.
The earlier posts on this blog are from the Fall 2009 semester; the course will be similar but not quite the same this semester. Nevertheless, the postings from last semester will give you a general idea of the kinds of assignments you'll be doing.

See you in class! Alej Garcia

Wednesday, October 6, 2010

Wednesday, September 29, 2010

Wednesday, September 15, 2010

Saturday, September 4, 2010

Thursday, August 26, 2010

Friday, August 20, 2010