3ds Max 2012 Bible - Kelly L. Murdock [477]
As an example of how this material can be used, consider the hot plate example. Rather than excluding objects from the Advanced Lighting calculations, you can instead use the Light Tracer panel to set the global settings for the scene and apply the Advanced Lighting Override material to the hot plate coils with a higher Color Bleed value. This causes the coils to bleed, but not the rest of the scene.
Another common use for this material is to use the Luminance Scale value to cause self-illuminating materials to add light energy to the global illumination calculations. In other words, increasing this value makes self-illuminating materials act as lights to the scene.
The Advanced Lighting Override material parameters, shown in Figure 45.15, let you set the amount of Reflectance, Color Bleed, Transmittance, Luminance, and Indirect Light Bump Scale that the material uses.
FIGURE 45.15
The Advanced Lighting Override Material rollout defines how light interacts with the material.
Lightscape material
The Lightscape material type lets you apply a material to objects that are imported from Lightscape. They are used to control how the radiosity is mapped to objects. The Basic Parameters rollout includes values for Brightness, Contrast, Ambient Light, and Bump Amount. You also can enable Daylight and Exterior Scene options. These values are applied in addition to the base material.
Using Lighting Analysis
To get information about the current lighting solution, you can use the Lighting Analysis Assistant. The scene must include a lighting solution before this tool is available. You can access this tool by selecting the Lighting Analysis menu command. This opens the Lighting Analysis Assistant dialog box, shown in Figure 45.16.
Note
This feature is available only in 3ds Max 2012 Design. •
FIGURE 45.16
The Lighting Analysis Assistant dialog box displays the light values at the specified location.
In order for the Lighting Analysis Assistant tools to work, you need to have a lighting solution for the current scene, and you need to have mental ray enabled using real-world parameters and photometric lights. If any of these conditions isn't met, it is indicated in the General panel and listed in bold. After making changes, you can press the Update Status button to recheck the settings. The General panel also includes a color spectrum that will be overlaid over the scene to show lighting values in different colors. This helps you identify places where the light isn't sufficient or where lights are too bright.
The Lighting panel shows the current lights applied to the scene and lets you edit their parameters from a single location. If any of the lights are invalid, then they will be identified in the Lighting panel. If you click the Select Invalid Light button, then any invalid lights are selected, and you can turn them on in the Modify panel.
The Lighting Analysis tools also require that all scene materials are physically correct using the mental ray architecture materials or the ProMaterials. Invalid materials are identified in the Materials panel, which can be a large number if you have a complex scene. The Materials panel includes a button to Assign Generic Valid Material to Selected Objects that can be used to quickly reassign any invalid materials.
The Analysis Output panel includes a button for creating Light Meters that can measure the light intensity at placed locations in the scene. Light Meters also can be created and placed using the Create⇒Helpers⇒LightMeter menu command. When you press the Calculate All Light Meters Now button in the Lighting Analysis Assistant dialog box, the scene is rendered and the light values are displayed within the viewports. This information also can be exported to a CSV file. Light Meters can be set to measure Total Illuminance, Direct Illuminance, Indirect Illuminance, or Daylight Factor.
The Lighting Output panel