chapter 13. storytelling through lighting, a cg perspective::

>>the objectives of lighting

  • directing the viewer's eye : the study of composition
  • creating depth
  • conveying time of day and season
  • enhancing mood, atmosphere, and drama
  • revealing character personality and situation

>>Light functions & placement

  • Ambient Light(or base llighting) :: with an ambient light + a few diffuse lights
  • Key Light :: for modeling of surface and setting of mood
  • Fill Light :: for subject contrast control
    a low-intensity light that fills an area that is in shadow or otherwise too dark. Fill lights are diffuse, which means that they give off a light that does not make objects look shinier. In computer graphics terms, these lights have no specular component
    high key-lots of soft fill lights
    low key - few fill lights
  • Backlight, rim Light :: for separation from BG and setting of mood
  • Kicker Light :: for surface modeling and character enhancement
    A kicker light defines edges on the opposite side of the key light.
  • Bounce Light :: to simulate radiosity effects

    • Usually, no specular, low intensity and colored to mimic the surface they are reflecting


(left to right) a) Key light. b) Fill light. c) Left rim light. d) Right rim light. e) Kicker light. f) Bounce light. g) All lights. © Disney/Pixar.

 

>>High Key & Low Key (from http://classes.yale.edu/film-analysis/htmfiles/mise-en-scene.htm)

  • high key : A lighting scheme in which the fill light is raised to almost the same level as the key light. This produces images that are usually very bright and that feature few shadows on the principal subjects. This bright image is characteristic of entertainment genres.
  • low key : A lighting scheme that employs very little fill light, creating strong contrasts between the brightest and darkest parts of an image and often creating strong shadows that obscure parts of the principal subjects. This lighting scheme is often associated with "hard-boiled" or suspense genres such as film noir.

 

>>Exercise with simple a still scene

Passes::
1. Key Light(spot): turn off 'recieved shadow' option forBG 2. Fill Light 1(spot) : turn off 'Emit specular'. dimmer than this image 3. Fill Light 2(spot) : to make BG shadow. turn off specular.
 
4. Rim Light(direct) : 5. Ambient Light : link with a plate only. to brighten shadow area  

Final images::

  

Single pass. no compositing. The differnece of the aboves is the angle of fill light which makes shadow on the wall. The wall of The left seems little bit flat. So I made smaller angle. The coners become more darken than the left. The aboves are rendered by MAYA SOFTWARE.

  

I renderd same image by MENTAL RAY for test. Ray trace was turned on for the left and it took 2 minutes or so(I guess...it felet so long...).
In this case, I prefer the right one. It's fast to render, contact shdows are there and the shadow are subtle. And I think something is needed for the BG(table and wall). They looked too obscure.

update 10/18/2005