682 Part V Cameras

Figure 26-5: Using the motion blur multi-pass effect for a camera, you can blur objects moving in the scene.

Summary

Cameras can offer a unique look at your scene. You can position and move them anywhere. In this part, you discovered how cameras work and how to control and aim them at objects. With Multi-Pass camera effects, you can add depth of field and motion blur effects.

In this chapter, you’ve

Used a multi-pass camera to create a Depth of Field effect

Used a multi-pass camera to create a Motion Blur effect

Although the director typically says, “Lights, camera, action,” we’ve switched the order to be cameras and then lights (action comes with animation later in the book). We just finished cameras, so next we move on to lights.

P A R T

Lighting

VI

In This Part

Chapter 27

Basic Lighting

Techniques

Chapter 28

Advanced Lighting

and Light Tracing

Chapter 29

Advanced Lighting

and Radiosity

Basic Lighting

Techniques

Lights play an important part in the visual process. Have you ever looked at a blank page and been told it was a picture of a polar

bear in a blizzard or looked at a completely black image and been told it was a rendering of a black spider crawling down a chimney covered in soot? The point of these two examples is that with too much or too little light, you really can’t see anything.

Light in the 3D world figures into every rendering calculation, and 3D artists often struggle with the same problem of too much or too little light. This chapter covers creating and controlling lights in your scene.

Understanding the Basics of Lighting

Lighting plays a critical part of any Max scene. Understanding the basics of lighting can make a big difference in the overall feeling and mood of your rendered scenes. Most Max scenes typically use one of two types of lighting: natural light or artificial light. Natural light is used for outside scenes and uses the sun and moon for its light source. Artificial light is usually reserved for indoor scenes where light bulbs provide the light. However, when working with lights, you’ll sometimes use natural light indoors, such as sunlight streaming through a window, or artificial light outdoors, such as a streetlight.

Natural and artificial light

Natural light is best created using lights that have parallel light rays coming from a single direction: You can create this type of light using a Direct Light. The intensity of natural light is also dependent on the time, date, and location of the sun: You can control this intensity precisely using Max’s Sunlight or Daylight systems.

The weather can also make a difference in the light color. In clear weather, the color of sunlight is pale yellow; in clouds, sunlight has a blue tint; and in dark, stormy weather, sunlight is dark gray. The colors of light at sunrise and sunset are more orange and red. Moonlight is typically white.

Artificial light is typically produced with multiple lights of lower intensity. The Omni light is usually a good choice for indoor lighting because it casts light rays in all directions from a single source. Standard white fluorescent lights usually have a light green or light blue tint.

27C H A P T E R

In This Chapter

Lighting basics

Understanding

Max’s light types

Creating and positioning light objects

Viewing a scene from a light

Altering light parameters

Using the Sunlight and

Daylight systems

Using the Volume light effect

Using projector maps and raytraced shadows

686 Part VI Lighting

A standard lighting method

When lighting a scene, not relying on a single light is best. A good lighting method includes one key light and several secondary lights.

A spotlight is good to use for the main key light. It should be positioned in front of and slightly above the subject, and it should usually be set to cast shadows, because it will be the main shadow-casting light in the scene.

The secondary lights fill in the lighting gaps and holes. You can position these at floor level on either side of the subject, with the intensity set at considerably less than the key light, and set to cast no shadows. You can place one additional light behind the scene to backlight the subjects. This light should be very dim and also cast no shadows. From the user’s perspective, all the objects in the scene will be illuminated, but the casual user will identify only the main spotlight as the light source, because it casts shadows.

Figure 27-1 shows the position of the lights that are included in the standard lighting model using a key light, two secondary lights, and a backlight. This model works for most standard scenes, but if you want to highlight a specific object, additional lights are needed.

Key light

Backlight

Secondary lights

Figure 27-1: A standard lighting model includes a key light, two secondary lights, and a backlight.

Chapter 27 Basic Lighting Techniques 687

Figure 27-2 shows an elk model that is rendered using different levels of the standard lighting model. The upper-left image uses the default lighting with no lights. The upper-right image uses only the key light. This makes a shadow visible, but the details around the head are hard to define. The lower-left image includes the secondary lights, making the head details more easily visible and adding some highlights to the antlers. The bottom-right image includes the backlight, which highlights the back end of the model and casts a halo around the edges if viewed from the front.

Figure 27-2: An elk model rendered using default lighting, a single key light, two secondary lights, and a backlight

The final type of light to keep in mind is ambient light. Ambient light is not from a direct source but is created by light that is deflected off walls and objects. It provides overall lighting to the entire scene and keeps shadows from becoming completely black. Global Lighting (including Ambient light) is set in the Environment panel.

Shadows

Shadows are the areas behind an object where the light is obscured. Max supports several types of shadows, including Area Shadows, Shadow Maps, and Raytraced Shadows.

Area Shadows create shadows based on an area that casts a light. It doesn’t require lots of memory, but it does support transparent objects. Shadow maps are actual bitmaps that the renderer produces and combines with the finished scene to produce an image. These maps can have different resolutions, but higher resolutions require more memory. Shadow maps typically create fairly realistic, softer shadows, but they don’t support transparency.

Max calculates raytraced shadows by following the path of every light ray striking a scene. This process takes a significant amount of processing cycles but can produce very accurate, hard-edged shadows. Raytracing enables you to create shadows for objects that shadow maps can’t, such as transparent glass. The Shadows drop-down list also includes an option called Advanced Raytraced Shadows, which use memory more efficiently than the standard Raytraced Shadows. Another option is the mental ray Shadow Map.