Pick up a clicker, find the right channel, and enter Student ID Upcoming Deadlines Homework #11 – Building a Scene in Maya Due Tuesday, November 22nd (Only class meeting next week) 20 points (10 points if late) For full schedule, visit course website: ArtPhysics123.pbworks.com
Homework #11 For this assignment you will create a simple scene; the assignment that follows will be to light the scene in a variety of ways. In both of these assignments you will be using Autodesk Maya, a popular software application used in animation. You can download a 30-day trial version of Maya from the Autodesk website.
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 simple scene was created by Candice Downey.
Homework #11 Alternative non-Maya Assignment: If you are unable to use Maya then create a scene like the one described above using real objects (blocks, books, etc.) and photograph the scene. In next week's assignment you will light this scene in a variety of ways so be sure that you can recreate it for that assignment. This assignment is due by 8am on Tuesday, November 22nd 20 points (if late, 10 points)
Survey Question How did your stop-motion character animation turn out? Very good Good Fair Poor Didn’t complete it
Review Question • The longer strings of a harp and the longer pipes of an organ produce sounds with: • Higher frequencies • Lower frequencies • Equal frequencies
Wavelength and Frequency B) Lower frequencies Longer strings and pipes produce sounds with longer wavelengths and thus lower frequencies. For example, if the length is doubled then the frequency is halved, lowering the note by one octave. Men and women typically sing an octave apart. High note C5 C4 Low note
Review Question When the forced vibrations match an object’s natural frequency the oscillations grow in amplitude due to synchronized transfer of energy into the vibrating object. This is called: Spectrum Acoustic Beat Surging Resonance Harmony
Acoustic Resonance D) Resonance If amplitude of the sound is sufficiently large, resonant vibrations can shatter a wine glass. http://www.youtube.com/watch?v=Pq-PxdOarjA
Review Question A musical instrument playing a single note produces not just that note’s frequency but others as well, mostly overtones. • The unique “signature” of an instrument’s spectrum is called: • Harmony • Melody • Timbre • Rhythm • Symphony
Why Instruments Differ C) Timbre The unique spectrum of frequencies for a musical instrument gives that instrument a unique signature, which is called the instrument’s timbre (or quality). Playing this note (196 Hz)
“Timbre” of a Material Spectrum of waves will be different for different materials due to density, viscosity, surface tension, depth of the fluid, etc. Jello waves Gushing Oil Well http://www.youtube.com/watch?v=pDyqhOL1ePU
Lighting Lighting is important in all the visual arts, from painting to cinematography. Humphrey Bogart in The Maltese Falcon (1941) The Orrery, Joseph Wright (1766)
Up (2009) Let’s look at how lighting in used in a a scene from Pixar’s Up.
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 Shadow Form Shadow
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
UMBRA 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. 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”
UMBRA 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) 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)
Penumbra UMBRA Penumbra 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). Light source 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
Sun Solar Shadows 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
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.
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.
1 2 3 4 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 Arm’s length Half
At twice the distance, the face is ¼ the size. At four times the distance face is 16th the size. Area & Distance 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. 5 light rays hit surface 7 light rays hit surface
Seasons of the Year 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. The seasons are reversed in January. Equator
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.
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 Rim Three-point lighting usually looks good but sometimes too good, that is, it seems fake. From Casablanca (1942)
Inconsistent Shadows The perspective in this painting is pretty good but what’s wrong with the shadows? The Birth of the VirginFra Carnevale, 1467
Inconsistent Shadows Variety of errors yet not immediately noticeable. Rising shadows? Downward shadow? No shadows? Long shadows from left to right The Birth of the VirginFra Carnevale, 1467
Inconsistent Shadows Frames of Reference, A. Garcia (2000)
Inconsistent Shadows Reference photos illustrate why the shadows are inconsistent in the final image.
Inconsistent Shadows This fake cutting that circulated during the 2004 Presidential primaries combined a photo of John Kerry was taken 1971 with one of Jane Fonda taken in 1972. The form shadows on their clothes are clearly inconsistent.
Next LectureReflection Homework #11 (Building a Scene in Maya) Due next Tuesday Please turn off and return the clickers!