1. 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

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

3. 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.

4. 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.

5. Homework #11
This scene was created by Tom McKee.

6. 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.

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

8. 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

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

10. Heat Transfer
C) Reduction
Radiation
Convection
Conduction

11. 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

12. 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

13. 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

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

15. 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

16. Optics & Lighting I: Lights and Shadows

17. 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)

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

19. Up (2009)

20. Up (2009)

21. Up (2009)

22. 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.

23. 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.

24. Cast Shadows & Form Shadows

25. 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

26. 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).

27. 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”

28. 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).

29. 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)

30. 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.

31. 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

32. 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.

33. 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

34. 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)

35. Moonrise Illusion
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.

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

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

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

39. Sun Rays & Perspective
This is what you think you see

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

41. Sun Rays & Perspective
Compare reality with perception

42. 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

43. 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.

44. 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.

45. 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

46. 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.

47. 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

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

49. 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

50. 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

51. 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

52. 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

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

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

55. 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)

56. Next Lecture Shading & Reflection
Homework #11 (Building a Scene in Maya)
Due on Tuesday of Next Week
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