WARNING Jagged edges on shadows can detract from the believability of your animation. Check some single-frame renders to see if your shadows are aliased.

Sample Range This parameter affects the softness of the edge of your shadow. A lower value averages a smaller range of pixels, making the edge sharper, with the potential for jagged aliased edges. Higher values average a larger range of pixels, softening the edge.

	WARNING If you set the sample range too high, you can get banding around the edges and drastically increase your render time. If you have the time and the RAM, you can reduce the streaking by increasing the map size (or by switching to raytraced shadows).

Raytraced Shadows

Raytraced shadows calculate the projection of the light more exactly. This is often called “more accurate,” so let’s consider what that means. It means that, if lighting in the real world behaved as CG lights do, shadows would look more like raytraced shadows, with exact, crisp edges and dark interiors. Since the raytracing calculation includes transparency, you can get more correct shadows of transparent and translucent objects. Raytraced shadows are also resolution-independent; they can be resized without getting the aliasing problems of shadow maps.

	TIP Using raytraced shadows is the only way to get the wire-frame material to cast a wireframe shadow.

The problem with raytraced shadows is those exact, crisp edges. In the real world, light is bouncing all around and shadows can have very soft edges. Those hard edges, for all the claims of accuracy, are not always realistic. You can improve the realism of raytraced shadows by reducing the Density setting. To summarize the pros and cons of raytraced shadows:

	TIP You can fake soft edges by rendering your shadows separately, using Matte/Shadow materials covered in Chapters 9, blurring them, and then compositing them back.

Overshoot

The Overshoot check box of spot and direct lights allows you to cast light outside the volume of the cone or cylinder. This allows you to limit shadows to within the falloff cone without limiting the illumination.

	TIP To simulate sunlight, check Overshoot on a direct light to illuminate the entire scene, but only cast shadows within the cylinder of the light.

Shadow Color

New to MAX R#,you can now choose a color to apply to your shadows.

	TIP Use Shadow Color to add depth through contrast according to the color shift principle described later in this chapter.

Map

Also new to MAX R3, you can now apply a map to blend with your shadow color in your shadows. This can be used to simulate refracted light through liquid, like the caustic shadow a glass of wine casts on to a table. You also need to check the box in front of the word Map in order to turn it on.

	NOTE The map applied to a shadow is not the same thing as shadow-mapped shadows. You can apply a map on top of both shadow-mapped and raytraced shadows.

Atmosphere Shadows

The Atmosphere Shadows check box enables a light to cast shadows of atmospheric objects such as fog. The opacity and coloration of the shadow can be set here, too. Atmospherics will be covered in more detail in Chapter 11.

Affecting Surfaces

The Affect Surfaces settings adjust how a light affects objects in the scene. Table 10.2 describes the effects of these settings.

	TIP Uncheck the Affect Specular check box to remove white “hotspots” or glares from the specular area of flat surfaces.

Projecting Maps from Lights

The Project Map settings, available for all types of lights in MAX, allow you to apply any map as a filter to generate interesting lighting effects. This kind of light is commonly called a gobo. Using an .avi or QuickTime movie will create a movie-projector effect.

	TIP Use animated noise maps on a gobo to create caustics on water surfaces. Project a gobo of leaf shadows onto a wall to simulate light passing through the leaves on a tree without having to model the tree.

Adding Atmospheric Effects

Volumetric lights are lights that shine in the air they pass through, rather than just on the objects they reach. The classic image of sunlight streaming into the Pantheon through the oculus in the dome is an example of volumetric light. In MAX, we use volume lights to create this effect; volume lights are essentially lights with fog in their path. The parameters of the fog can be adjusted for different effects, as we will cover in Chapter 11.

Lens effects simulate the glows and distortions made when shooting light through a lens (a camera or your eye). An example of this is the glow we see around a light shining straight at us and shooting off into spikes of light. Lens effects will also be covered in Chapters 11 and 12.

Prior to MAX R3, volumetric effects could only be assigned to lights through the Rendering Ø Environment dialog box, and lens flares could only be assigned through Video Post. You can still use these methods, but now you can also use the Atmospheres & Effects rollout of a light object. Use the Add button to bring up the Add Atmosphere or Effect dialog box. The Delete button, obviously, deletes the volumetric or lens effect from the light.

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