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Chapter 20: Using Lights and Basic Lighting Techniques

Note
You can create shadows for wireframe objects with transparency only by using raytraced shadows. n
In the Shadow Parameters rollout, you can select whether shadows are computed using shadow maps or
raytraced shadows. Using the latter selection lets you project a transparent object’s color onto the shadow.

Tutorial: Projecting a trumpet image on a scene
As an example of a projector light, you create a musical scene with several musical notes and project the
image of a trumpet on them.
To project an image onto a rendered scene, follow these steps:
1. Open the Trumpet mask.max file from the Chap 20 directory on the DVD.
This file includes a trumpet model shown in the maximized Left viewport. This file is used to gen-
erate a project map.
2. Choose Rendering ➪ Render (or press the F10 key) to open the Render dialog box; set the resolu-
tion to 640 × 480, and select the Left viewport. Then select the Render Elements tab, and click
the Add button. Select Alpha from the Render Elements dialog box, click OK, and then click the
Render button. The side view of the trumpet in the Rendered Frame Window renders along with
an alpha channel rendering of the trumpet. When the rendering completes, click the Save File
button in the Rendered Frame Window for the alpha channel and save the file as trumpet
mask.tif.
3. Open the Musical notes.max file from the Chap 20 directory on the DVD.
This file contains several musical notes created from primitive objects.
4. Select the Create ➪ Lights ➪ Standard Lights ➪ Target Spotlight menu command, and drag to cre-
ate two lights in the Top viewport. Position the first spotlight to be perpendicular to the scene
and to shine down on it from above.
5. Open the Modify panel; in the Advanced Effects rollout, click the Projector Map button and dou-
ble-click Bitmap from the Material/Map Browser. Locate and select the Trumpet Mask.tif file, and
click Open. This projects a silhouette of a trumpet onto the scene. Use the second spotlight to
light the music notes.
Figure 20.18 shows the musical notes with the trumpet projection map.
Tutorial: Creating a stained-glass window
When a light that uses raytraced shadows shines through an object with transparent materials, the Filter
color of the material is projected onto objects behind. In this tutorial, you create a stained-glass window
and shine a light through it using raytraced shadows.
To create a stained-glass window, follow these steps:
1. Open the Stained glass window.max file from the Chap 20 directory on the DVD.
This file includes a stained-glass window for a fish market. (Don’t ask me why a fish market has a
stained-glass window.)
2. Select the Create ➪ Lights ➪ Standard Lights ➪ Target Spotlight menu command, and drag in the
Left view from a position to the right and above the window to the window.
This creates a target spotlight that shines through the stained-glass window onto the floor behind it.
3. In the General Parameters rollout, make sure that the On option is enabled in the Shadows sec-
tion and select Ray Traced Shadows from the drop-down list.

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