Upcoming Deadlines Pick up a clicker, find the right channel, and enter Student ID Homework #11 – Building a Scene in Maya Due Tuesday, May 1st 20 points (10 points if late) Homework #12 –Cameras and Lights in Maya Due Tuesday, May 8th For full schedule, visit course website: ArtPhysics123.pbworks.com

Second Term Paper The following persons did not turn in their second term paper in on time: 6495047 5760521 7687693 5862857 The term papers will be graded over the next two weeks, hopefully even sooner.

Homework #11 For this assignment you will create a simple scene using Autodesk Maya, a popular software application used in animation. You can download a 30-day trial version of Maya from the Autodesk website. You will also use Maya in Homework #12 where you will try to recreate the camera and lighting for a simple composition.

Homework #11 The scene that you create in this assignment consists of a floor, a single wall in the background, and some objects in the foreground. Those objects need to be arranged so that they create the shape of the initials of your name. Position the two letters so that they rest on the floor or on each other; do not have them touching the vertical wall.

Homework #11 This scene was created by Tom McKee.

Homework #11 Post your rendered image on blog in an entry entitled “Building a Scene in Maya.” Due by 8am on Tuesday, May 1st 20 points (if late, 10 points) Extra Credit (10 points): Create images of your scene lit using one-point, two-point, and three-point lighting.

Homework #11 Two-point Lighting One-point Lighting Three-point Lighting

Survey Question What grade do you expect to get in this course? A (400 points or more) B (300 points or more) C (200 points or more) D or below (Below 200 points) Have no idea

Review Question Which of these is not a mechanism for heat transfer? Conduction Radiation Reduction Convection

Heat Transfer C) Reduction Radiation Convection Conduction

Review Question Flowing electrons strike atoms in a conductor, heating the material. This type of heating is named after: André-Marie Ampère Nicola Tesla Thomas Edison Georg Ohm Alessandro Volta Toaster

Ohmic Heating Georg Ohm Georg Simon Ohm (1789 –1854) was a German physicist. As a high school teacher, Ohm began his research with the recently invented electrochemical cell, invented by Italian Count Alessandro Volta. Using equipment of his own creation, Ohm determined that there is a direct proportionality between the potential difference (voltage) applied across a conductor and the resultant electric current – now known as Ohm's law. Georg Ohm Ohmic heating is also called Joule heating, first studied by James Prescott Joule in 1841

Review Question True or False Electrocution (death by electric shock) is usually due to ohmic heating of the internal organs of the body. True or False

Electrocution False It is due to the disruption of the nervous system, especially that which controls the heart beat.

Nervous System Nervous systems in animals use electrical currents to signal the contraction and relaxation of muscles. The most important electrical signal in our body is the periodic signal that contracts and relaxes our heart muscle to pump blood. Without a constant flow of blood the brain can suffer permanent damage. SA AV

Optics & Lighting I: Lights and Shadows

Lighting Lighting is important in all the visual arts, from painting to cinematography. The Orrery, Joseph Wright (1766) Humphrey Bogart in The Maltese Falcon (1941)

Up (2009) Let’s look at how lighting in used in a scene from Pixar’s Up.

Up (2009)

Up (2009)

Up (2009)

Key Lighting (One-Point) Simplest type of lighting is with a single dominant light source, called the key. Traditionally, this light source is located on the left side of the scene.

Utah Teapot The Utah teapot or Newell teapot is a 3D computer model which has become a standard reference object (and an in-joke) in the computer graphics community. It is a mathematical model of an ordinary teapot of fairly simple shape, which appears solid, cylindrical and partially convex. The teapot model was created in 1975 by early computer graphics researcher Martin Newell at the University of Utah.

Cast Shadows & Form Shadows

Cast Shadows Size and sharpness of a cast shadow depends on: Size of the light source Distance from light to object Distance from light to wall

Cast Shadow for Directional Light A directional light has parallel light rays so the cast shadow is simple to trace on the wall. Dark shadow called the umbra. UMBRA Object Wall Shadow is sharp (not fuzzy).

Creating Directional Light Light sources, such as bulbs, send light in all directions; directional lighting is created with mirrors or lenses to form the light into a beam. “Barn doors”

Cast Shadow for Point Light Source Light rays spread out from a point light source, such as a bright light bulb or a candle. Light source (Point) UMBRA Object Wall Size of shadow depends on: * Distance from the light to object * Distance from object to wall Shadow is sharp (not fuzzy).

Film Noir Shadows Film noir makes extensive use of cast shadows, manipulating their size for dramatic effect. I Confess (1953) M (1931) Shadow Of A Doubt (1943)

Cast Shadow for Area Lights Rays from a large light source to wall to map out location of deep shadow (umbra) and fuzzy shadow (penumbra). Penumbra Light source UMBRA Object Wall The larger the light source, the smaller the umbra.

Umbra and Penumbra No Shadow An ant on the ground standing in the penumbra could see part of the sun. Standing in the umbra part of the shadow, the ant wouldn’t see the sun at all. Penumbra Umbra

Penumbra Size Notice how the size of the shadows’ penumbra increases as the shadow gets farther from the base of the tree. Very far from the base the penumbras on each side meet and there’s no more umbra.

Solar Shadows Sun Diagram is not to scale The width of the penumbra for a shadow cast by the Sun equals about 1% of the distance from the object to its shadow. ( Angle = ½ degree Object Distance Example: If an object is 9 feet (108 inches) from the ground, the penumbra is a little more than 1 inch wide. ) LIGHT UMBRA Penumbra Floor

Size of the Sun and Moon In the sky, the sun and the moon are about the size of a dime viewed from a distance of six feet. Paintings with the sun or the moon rarely show it at the correct size for the distance at which the painting is normally viewed. The Starry Night, van Gogh (29 in × 36¼ in)

Moonrise Illusion http://antwrp.gsfc.nasa.gov/apod/ap020130.html Is the Moon larger when near the horizon? No, the Moon is very nearly the same size no matter its location on the sky. In this time-lapse sequence, the Moon was re-imaged every 2.5 minutes, with the last exposure of longer duration to show the panorama of Seattle. The illusion occurs because foreground objects make a horizon Moon seem to be farther in the distance. The mind interprets more distant objects as wider; furthermore the distance illusion may make the eye focus differently.

Sun Rays See rays because part of the light is blocked by clouds

Fog Shadows Shadow seen due to scattering by fog of the non-shadowed light rays. Fog shadow of TransAmerica building.

Sun Rays & Perspective Light from the sun is nearly parallel so we see spreading ray pattern due to perspective.

Sun Rays & Perspective This is what you think you see

Sun Rays & Perspective This is what the sun’s rays are actually doing

Sun Rays & Perspective Compare reality with perception

Shadows & Perspective These photos show the long shadows cast by tall mountains at sunset, with the moon rising near the horizon. Mauna Kea, Hawai'i Notice the shadows’ sharper peaks, due to convergence of lines by perspective. Mt. Teide, Canary Islands

Lighting and Dimension Intensity of light striking a surface varies with angle so the gradient created by a key light is a strong visual cue of an object’s curvature and shape.

Light Intensity & Distance The intensity of light decreases as we get farther from the light source. The light gets weaker because it is spread over a larger area. For a point light the intensity decreases quadratically, that is, at twice the distance you have a four times less intensity.

Demo: Perspective Cards Hold large card at arm’s length. Close one eye then hold small card at a distance such that it is same size as large card. That distance will be half way between your eye and large card. 1 2 3 4 1 Arm’s length Half

Area & Distance These four figures are equally spaced in At four times the distance face is 16th the size. At twice the distance, the face is ¼ the size. These four figures are equally spaced in distance and, in perspective, you are standing that distance from the first.

Light Intensity & Angle As angle between the light and a surface increases, the intensity of the light on the surface decreases because it is spread over a larger area. 7 light rays hit surface 5 light rays hit surface

Summertime True or False It’s hotter in the summertime because in July the Earth is closer to the sun. True or False

Seasons of the Year False. Northern Hemisphere is warm in July because Earth is tilted towards the Sun. Southern Hemisphere is cold in July since it’s tilted way from the Sun. Equator January in Brazil

Form Shadow for Point Light Source The form shadow is completely dark if point source is the only light source (i.e., no ambient or reflected light). Object Light source (Point) Object is brightest where the rays hit head-on and dims going up to the terminator. Terminator

Form Shadow for Area Light Source Terminator widens into a penumbra for an area light. A B C Light source (Area) View from A View from B View from C

Ambient Light Ambient Ambient Direct Direct Most lighting is indirect, coming not from a light source but from reflections off of other surfaces. Direct Ambient

Fill Lighting Key Key+ Fill With two-point lighting the fill light softens the contrast by adding ambient light. Fill

Rim Lighting Key+ Fill Key+ Fill+ Rim Adding a rim light shining from behind distinguishes the foreground objects from the dark background. Rim

Three-point Lighting Three-point lighting (Key, Fill, and Rim) is a formula that Hollywood has used for years. Key+ Fill+ Rim Three-point lighting usually looks good but sometimes too good, that is, it seems fake. From Casablanca (1942)

Next Lecture Shading & Reflection Homework #11 (Building a Scene in Maya) Due on Tuesday of Next Week Please turn off and return the clickers!