The first topic in the lesson is ambient light. This is light that comes from objects in a scene, not from light sources. It is light that radiated from some light source, hit objects in the scene, and is now bouncing back from those objects (that do not radiate light themselves). It can be thought of as reflected light or indirect light. Think about walls in rooms. Why do we paint the walls of a room a light color when we want to brighten the room? It is because light colors reflect more light than dark colors, adding to the amount of ambient light in a room.
3DS Max does have an ambient light feature, but it does not produce the result we might want. You may have noticed in the underwater lesson that the ambient light in a 3DS Max scene is set to black by default. The problem is that virtual surfaces don't work exactly like real surfaces, so the lesson will show us how to use secondary light sources to produce the effect of ambient light.
Exercise Notes and Questions
Work through the exercises and turn in your answers to all questions below as part of the homework for this assignment.
Exercise 1: Open the the indicated file.
In photographic terms, you just added a fill light to the scene. It lets you see the side of the subject that was not lit in the beginning. More on this idea in a bit.
The text explains that you will use three categories of lights in 3DS Max, but it dashes our hopes of simplicity by endlessly subdividing the categories. Let's do what we can to simplify it:
More terminology about light is offered. Light in a scene can vary in color as well as in intensity. As you add more lights to a scene, you will want to consider both qualities. Mixing colors can be artistic, or it can be a case of less (fewer colors) being more (better output). Adding lights to a scene adds to the total light level. You may want to adjust the level of each light so that the total light in the scene is not more than you want or need. It is not immediately clear how to change the color of a light. Set the color by clicking the unlabeled panel next to the Multiplier field on the Intensity/Color/Attenuation rollout.
A word most people have not heard is attenuation, which means fading over distance. In the real world, the farther light travels, the more it fades in intensity. It follows what is called the inverse square law in physics. Think about standing two feet from a lamp. Its light has a certain intensity, or brightness. Now walk four feet from the lamp. The light must travel twice as far to you. Its intensity will be 1 over the increase in distance (2, because you doubled the distance) squared. 1/2*2 = 1/4. The light will be one quarter as bright when twice as far away.
In 3DS Max, we can control attenuation. We can set where it begins and ends, we can set an attenuation (decay) rate, or we can turn it off. All of which looks unrealistic, but may help fake realism in a scene where we do not notice the light sources. (Inverse square is one of the decay rate choices.)
Shadows are discussed and demonstrated in the next exercise. The text presents the idea that shadows add to the realism of a scene, and we should study placing them to best effect. Two types of shadow generation are discussed:
Other methods are mentioned, but no details are offered.
Exercise 2: The text suggests we reset the program before continuing. We are using more render functions now, so it is a good idea.
In step 13 you turn on the shadows. You render again and see the problem with a shadow map: glass does not cast the same kind of shadow as pewter, but shadow map thinks it does,
The text turns to lighting techniques. It tells us that there are many techniques, but it only describes one classic: three-point lighting. Three kinds of lights are used in this method:
Exercise 3: This exercise shows you what can happen using a three-point lighting technique.
As a matter of fairness, I will suggest that when you finish step 29, you should render the scene, then save it with a new name. Then you can open the 3-point Final.max file and see the author's render. Before you feel bad about it, notice two things: that render looks a lot like the final version in step 29, and the lights in the scene look only a little like the ones we were told to make.
One more short topic: the Light Lister is a tool for managing the lights in your scene. Exercise 4 shows you some settings you can check and change on it.
Exercise 4: Open the indicated file. Open the Tools menu (third item on the menu bar) and select Light Lister.