tutorial: three-light technique for lighting

this tutorial is based on the work of John Kahrs, Lighting for Computer Graphics, Pixel Cinematography Course notes, Siggraph '96


The basic key/fill/rim lighting combination is a standard live-action approach that has been around for a long time.

The Key light is the primary source of illumination.
The Fill light softens and fills the shadows created by the Key.
The Rim or Kicker is a backlight that provides highlights and rim lighting around the edge of the subject. It is often what differentiates the subject from the background.

basic_setup download maya scene file

download studio wire file
original setup, one spot dead center makes the subjects look flat and uninteresting.


key_light

Start with one keylight, in this case a spotlight, angled at 3/4 placement


fill_light

Next, turn off the key and work with the fill light, created with a low-intensity ambient and spot with intensity, neither cast shadows. Use the fill to lighten up the dark areas on the right side of the figures. The Fill is positioned on the opposite side of the key in this case.


Now turn the key back on and view the key and fill lights together


Turn the key and the fill off and work with the Rim light to give you highlights on the edges of the figures. This Rim light will also cast shadows.


Key/Fill/Rim together


the decay and dropoff were added and the fill's intensity was bumped up


side and top view of light layout


Assignment description:
This tutorial will introduce the student to the use of a three-light setup for lighting in a scene.

Students will download the provided Maya or Studio scene file which contains the models without lights. All of the shaders for models are provided in the file. The correct camera angle which is the current perspective camera. Students will create a lighting model that takes into consideration all light sources and reflected light that appear in the provided scene.

This project will result in the creation of still images which display a defined lighting situations.
Students will email the instructor typed answers to the questions below.

Technical Requirements:

  1. half-resolution image of the key light source alone
  2. half-resolution image of the fill light source alone
  3. half-resolution image of the key and fill together
  4. half-resolution image of the back light source alone
  5. half-resolution image of the key, fill and back together
  6. half-resolution image of #5 with decay and dropoff added

Questions:

  1. What is the function of a key light?
  2. List 3 characteristics or facts about key lights
  3. What is the function of a fill light?
  4. List 3 characteristics or facts about fill lights
  5. What type of light is usually fill light?
  6. Name two types of fill light
  7. What is the function of a back light?
  8. List 3 characteristics or facts about back lights
  9. From what direction does back light typically come?
  10. What are the other names for the back light?
  11. Where is a kick light typically positioned?
  12. What is decay in Maya's digital lighting?
  13. What is dropoff in Maya's digital lighting?
  14. How does dropoff effect the look of shadows?
  15. List and describe 3 types of supplementary lights