Distant lights and point lights produce hard-edged, ray-traced shadows. Ray-traced shadows take more time to calculate, which of course means more time to render. Spotlights also can produce ray-traced shadows, but with spotlights you have the option to use shadow maps, which take less time to render than ray-traced shadows. Softer than ray-traced shadows, shadow maps use more memory to render than ray-traced shadows. Ray-traced shadows use more processing power.
Area lights also can produce realistic ray-traced shadows, but to do so they require more rendering time. For example, say a person is standing outside in bright sunlight. The shadow that the person casts has sharp edges around the area by the subject’s foot, where the shadow begins. As the shadow falls off and away from the subject, it becomes softer. Ray-traced shadows from distant lights, point lights, and spotlights cannot produce this effect—neither can shadow maps. Only area lights can produce these true shadows and create a softer overall appearance to animations.
Spotlights are the most common lights, and they are the most useful for your everyday animation needs. But on occasion, the added rendering time generated from area lights is worthwhile. An area light is represented in Layout by a flat square and emits light equally from all directions except for the edges, producing very realistic shadows.
Exercise 4.5 Working with Area Lights
1. Continuing from the scene you’ve been working on throughout this topic, select Key_Light, and press p to open the Light Properties panel. Change Light Type from Spotlight to Area Light.
2. Change the Light Intensity setting to 60%. Keeping the default 100% Light Intensity setting would be too bright, and the image would appear washed out. Area lights are much "hotter" than spotlights and also give you more control.
3. Move the Light Properties panel aside and return to Layout.
4. If the new area light is not selected, select it and change your Layout view to Perspective to get an overall view of the scene. Figure 4.27 shows the Perspective view. The area light appears as a box outline. This light is already positioned above and to the left of the teacup object. It’s here because you originally set the key light in this position. All you’ve done now is change the type of light you’re using. Everything else, such as position and rotation, has remained the same.
Figure 4.27 The single area light can create beautiful shadows, even on a simple object.
Note
To help set up lights in Layout, change the Maximum Render Level setting to Textured Shaded Solid.You can find this setting by clicking the drop-down arrow to the right of the viewport style buttons at the top of Layout. Make sure Max OpenGL Lights is set to at least 1 or above from the Display Options panel (press d).Also, always make sure that the Affect OpenGL option for the light in the Light Properties panel is turned on.This makes the light source’s effect visible in Layout, and helps you line up the direction of the light source.
5. In Layout’s Render tab, click Render Globals and then, on the Render Globals panel’s Render tab, check Ray Trace Shadows to have LightWave calculate shadows for the area light, as shown in Figure 4.28.
Note
While you’re in the Render Options panel, make sure you choose a Preview setting, such as 320 x 240.This enables you to see the render as it’s being drawn.Also make sure that Render Display is set to Image Viewer to see a full-sized version of your render when it’s complete.The full-sized version will be 640 x 480, as this is its resolution setting by default. You can also change this setting in the Render Globals panel.
Figure 4.28 You tell LightWave to calculate Ray Trace Shadows while rendering from the Render Globals panel.
6. Press F9 to render the current frame. You’ll see that the shadow has a soft edge, as shown in Figure 4.29. But the light itself is a bit too hot, and the teacup is washed out in spots.
Figure 4.29 The default area light casts a sufficient shadow, but the light it casts might be a little hot.
Note
The cool thing about area lights is that you can size them. Because the area light here was originally a spotlight, its size has remained. If, however, you created a new area light,you would need to increase the size to soften the shadows. By increasing their size,you soften their shadows. Don’t forget to keyframe any size changes.You can use the Size tool on the Modify tab.Try it out!
7. In Layout, select the area light, and then press p to open the properties panel. Change the Light Intensity setting to about 45%.
8. Press F9 to perform another render. Figure 4.30 shows the render with less intensity. Note
If you increase the size of the area light, the shadow softens. However, it might appear grainy or jagged. If so, simply increase the Area Light Quality setting in the Light Properties panel.The default is 4—good for most renderings. Often setting a value of 5 works slightly better but takes more render time. Isn’t that always the case? Note that 5 is your maximum value.
Figure 4.30 You can resize an area light for softer shadows, and by bringing the light intensity down, the light’s effect is not as hot.
Sizing a light might seem odd, but it helps spread the amount of light and thereby the shadow as well. Notice in Figure 4.30 that the shadow is soft and very realistic. Area lights take a long time to render, but they produce the best results.
Here are a few more things to remember when using area lights:
• Quality settings can be adjusted. The default Area Light Quality setting of 4 results in 16 samples per area light. Values of 2 and 3 result in 4 and 9 samples per area light, respectively.
• Linear lights perform like area lights but emit light from a two-point polygonal shape, similar to a fluorescent tube.
• You can mix spotlights, distant lights, point lights, and linear lights with area lights for added effects.
