Upcoming Deadlines Second Term Paper Wednesday, November 25 th (Day before Thanksgiving; no class that day) Homework 11 (Building a scene in Maya) Monday, November 30 th (Monday after Thanksgiving) Homework 12 (Lighting a scene in Maya) Monday, December 7 th (Last day of class) For full schedule, visit course website: ArtPhysics123.pbworks.com

Guest Lecture Prof. Raquel Coelho will give a special lecture on lighting in computer generated images. In class, Wednesday, Nov. 18 th Coelho has worked for studios such as Blue Sky and PDI/Dreamworks, Wildbrain Inc and Tippett Studio, as animator in films such as "Charlotte's Web", "Hellboy", "The Spiderwick Chronicles" and "Happy Feet".

Homework Assignment 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 Assignment 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 Assignment This simple scene was created by Candice Downey.

Homework Assignment Do not include anything else in the scene; keep it clean so that the two letters are distinctly seen without any other distracting elements. Most of your grade will be based on correctly following these instructions however extra points will be awarded to creatively constructed letters and interesting compositions within the scene.

Homework Assignment After downloading and installing Maya, watch the tutorials on how to perform basic tasks. Build your scene using polygon objects ("Polygons" tab) and/or NURBS surfaces ("Surfaces" tab). When the scene is complete, select the "Rendering" tab and press the "Render Current Scene" button. Once the scene looks like you'd like, in the Render View window save it as a JPEG file and upload it to your blog in an entry called "Building a Scene in Maya." Save the Maya file containing your scene since you'll need it for the next assignment.

Homework Assignment 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 Monday, November 30th. 20 points (if late, 10 points)

Special Campus Event Animation Show of Shows December 7 th (Monday) At 7:30 PM Morris Dailey Auditorium in Tower Hall FREE

Extra Credit Opportunity Visit the Alexander Calder exhibition at the San Jose Museum of Art. Exhibition runs through Dec. 13. Give me your ticket receipt for five points extra credit. Big Red, 1959 Hours: Tuesday – Sunday, 11am - 5pm Admission: $5.00 for students Location: 110 South Market St., Next to Fairmont Hotel, downtown SJ

Extra Credit Opportunity Exhibition runs through Jan. 10. Give me your ticket receipt for ten points extra credit. Hours: Tuesday – Sunday, 11am - 5pm Admission: $4.00 for students Location: 655 Mission Street San Francisco, California Near Moscone Convention Center Visit the Cartoon Art Museum in San Francisco to see “Once Upon a Dream: The Art of Sleeping Beauty.”

Extra Credit Opportunity Give me your ticket receipt for ten points extra credit. Hours: Wednesday-Monday: 10a.m.-6p.m Admission: $15.00 for students Location: 104 Montgomery Street Inside The Presidio of San Francisco Visit the Walt Disney Family Museum in San Francisco (opens Oct. 1 st ).

Extra Credit Opportunity Give me your ticket receipt for ten points extra credit. Hours: Tuesday-Sunday: 10a.m.-5p.m Admission: $11.00 for students Location: 3601 Lyon Street, SF Next to Palace of Fine Arts complex Visit the Exploratorium in San Francisco.

Optics & Lighting Part I: Ray Tracing

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 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.

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

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 Arm’s length Half

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

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

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.

Shadows Size and sharpness of a shadow depends on size and distance of the light source and of the object casting the shadow.

Shadows 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. No Shadow Penumbra Umbra

Ray Tracing for Shadows UMBRA Penumbra Light source Object Wall Trace rays from light source to wall to map out location of deep shadow (umbra) and fuzzy shadow (penumbra).

Solar Shadows UMBRA Penumbra Sun Object The width of the penumbra for a shadow cast by the Sun equals about 1% of the distance from the object to its shadow. Floor Angle = ½ degree ( ) Distance Diagram is not to scale

Penumbra Size Notice how the size of the penumbra increases as the shadow gets farther from the base of the tree.

Inconsistent Shadows The Birth of the Virgin Fra Carnevale, 1467 The perspective in this painting is pretty good but what’s wrong with the shadows?

Inconsistent Shadows The Birth of the Virgin Fra Carnevale, 1467 Long shadows from left to right No shadows? Rising shadows? Downward shadow? Variety of errors yet not immediately noticeable.

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

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

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

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

Specular and Diffuse Reflection Reflection from most surfaces is diffuse, with incoming light scattered in all directions. Reflection from mirror surfaces is specular, with light reflecting in one direction. Mirror Diffuse reflection Specular reflection

Lambert Diffuse Reflection The apparent brightness of a Lambert surface is the same regardless of the observer's angle of view. This is typical of matte surfaces, such as paper and cloth. In computer graphics, Lambertian reflection is often used as a model for diffuse reflection. The visual effect is that rotating or scaling the object does not change the apparent brightness of its surface Key + Fill Key only

Phong Reflection Phong reflection is a surface model combining the diffuse reflection of rough surfaces with the specular reflection of shiny surfaces. Shiny surfaces have small intense specular highlights, while dull surfaces have large highlights that fall off more gradually. The model also has an ambient term to account for the fill lighting.

Law of Specular Reflection Angle of incidence equals angle of reflection SPECULAR REFLECTION

Demo: Blackboard Optics Special blackboard has mounted light source and mirrors. Light Source Mirror Demonstrates the Law of Reflection Incident Reflected

Ray Tracing Light ray from point A is reflected at point B and arrives at point B. Notice the relationship between point B (where the ray is reflected to) and point B’ (where the ray would go if the mirror wasn’t there).

Demo: Who Do You See? A B C D E MIRROR Which person in the front row sees the guy with the hat in the mirror?

A B C D E Demo: Who Do You See? Diffuse light MIRROR Person A sees the guy with the hat when looking in the mirror. The converse is also true: Person E sees Person A in the mirror.

Finding the Highlight A B C D: None of these Lamp Where does Abe see the highlight reflected off this metal block? Abe

Finding the Highlight Lamp Abe C Light rays from point C reach Abe.

No Highlight for Diffuse Surface Lamp Abe Same amount of light from all points of a Lambert diffuse surface. This end will be brighter only because it’s closer to the lamp.

Diffuse Surface is Not a Mirror Light rays diffusely scatter in every direction from every spot on the surface. See a light ray from the top of your head reflected from this spot. Also see light ray from the tip of your nose reflected from this spot. Look at this spot on a diffuse surface

Plane (Flat) Mirror Tracing light rays from original, to mirror, to eye allows us to construct image. Original Image Mirror HAIR NOSE CHIN

Demo: Pocket Mirror See full image of your head in a plane mirror that’s half the size of your head. Original Image Mirror

Image in the Mirror Utamaro, Woman Powdering Her Neck Velazquez, Venus at her Mirror Helmut Newton, Bergstrom over Paris Which work of art has a correct reflection? Incorrect Correct

Next Lecture Guest Lecture: Lighting in CG Animation Campus closed on Wednesday & Friday Please return the clickers!