3ds Max 2012 Bible - Kelly L. Murdock [473]
1. Open the Hotplate.max file from the Chap 45 directory on the CD.
This file includes a simple model of a hotplate.
2. Open the Advanced Lighting panel by selecting Rendering⇒Light Tracer (or press the 9 key). In the Parameters rollout, set the Object Multiplier to 10, the Color Bleed to 25, and the Bounces to 1.
3. Select the Rendering⇒Environment (8) menu command to open the Environment and Effects panel. In the Exposure Control rollout, select the Linear Exposure Control option and enable the Process Background and Environment Maps option. In the Linear Exposure Control Parameters rollout, adjust the Brightness to 40 and click the Render Preview button to see a quick preview of the results in the Exposure Control rollout.
4. In the Render Scene dialog box, click the Render button.
This renders the scene in the Rendered Frame Window.
Caution
Remember that selecting an advanced lighting option greatly increases the render time. •
Figure 45.4 shows the scene rendered with advanced lighting.
FIGURE 45.4
Color bleeding happens only when global illumination is enabled.
Using Local Advanced Lighting Settings
You can set advanced lighting settings locally for specific objects using the Object Properties dialog box, as shown in Figure 45.5.
At the top of the Advanced Lighting panel in the Object Properties dialog box is the number of selected objects and lights. The Object Properties dialog box is opened using Edit⇒Object Properties. This dialog box lets you specify whether this object should be excluded from the advanced lighting calculations. The properties can be set By Object or By Layer. If included, you can select whether the object casts shadows, whether it receives illumination, and how it handles radiosity. The Number Regathering Rays Multiplier option sets the number of rays cast by the selected object. For large, smooth surfaces, reducing artifacts by increasing this value can be helpful. The remaining settings in this panel deal with radiosity.
FIGURE 45.5
Use the Advanced Lighting panel in the Object Properties dialog box to disable advanced lighting.
Tutorial: Excluding Objects from Light Tracing
Using the Object Properties dialog box, you can exclude certain objects from the light tracing calculations.
To exclude objects from the Light Tracer, follow these steps:
1. Open the Hotplate.max file from the Chap 45 directory on the CD.
This file includes a simple model of a hotplate.
2. Open the Advanced Lighting panel by selecting Rendering⇒Light Tracer (or press the 9 key). In the Parameters rollout, set the Bounces value to 2.
3. In the Front viewport, select the plug, cord, and floor objects, and then select Edit⇒Object Properties to open the Properties dialog box for these objects. In the Object Properties dialog box, open the Advanced Lighting panel and enable the Exclude from Advanced Lighting Calculations option. Then click OK.
4. In the Render Scene dialog box, click the Render button.
This renders the scene in the Rendered Frame Window.
Figure 45.6 shows the scene rendered with advanced lighting that excludes certain objects.
FIGURE 45.6
Color bleeding becomes much stronger with a higher Bounce value.
Understanding Radiosity
Imagine a scene that includes an umbrella with a light source directly overhead. If you rendered the scene, the object caught in the umbrella's shadow would be too dark for you to see clearly. To fix this situation, you would need to add some extra lights under the umbrella and set them to not cast shadows. Although this workaround provides the solution you want, it is interesting to note that this isn't the case in real life.
The difference between the workaround and real life has to do with the effect of light energy being reflected (or bounced) off the lit objects. It is this phenomenon that allows me to look down the hall and see whether my children's light is still on past bedtime. Even though I can't see the light directly, I know it is on because of the light that reflects