Using the MatteShadow Material


Using the Matte/Shadow Material

You can apply matte/shadow materials to objects to make portions of the model invisible. This lets any objects behind the object or in the background show through. Objects with matte/shadow materials applied can also cast and receive shadows. The effect of these materials is visible only when the object is rendered.

Matte/Shadow Basic Parameters rollout

You can apply a matte/shadow material by clicking the Type button and selecting Matte/Shadow from the Material/Map Browser. Matte/shadow materials include only a single rollout: the Matte/Shadow Basic Parameters.

The Opaque Alpha option causes the matte material to appear in an alpha channel. This essentially is a switch for turning Matte objects on and off.

You can apply atmospheric effects such as fog and volume light to Matte materials. The At Background Depth option applies the fog to the background image. The At Object Depth option applies the fog as if the object were rendered.

CROSS-REF 

Find out about Atmospheric effects in Chapter 44, "Using Atmospheric and Render Effects."

The Receive Shadows section enables shadows to be cast on a Matte object. You can also specify the Shadow Brightness and color. Increasing Shadow Brightness values makes the shadow more transparent. The Affect Alpha option makes the shadows part of the alpha channel.

Matte objects can also have Reflections. The Amount spinner controls how much reflection is used, and the Map button opens the Material/Map Browser.

Tutorial: Ballooning in New York

Touring New York City can be exhilarating and exasperating at the same time, but the real way to tour New York City is by balloon (or by virtual balloon). This way, you won't have to worry about the crowds or bustle, but taking the subway might be a little difficult. In this tutorial, we visit the Statue of Liberty in a balloon and use a Shadow/Matte material to fly the balloon behind the statue.

To use a matte/shadow material to hide geometry, follow these steps:

  1. Open the image from book Balloon over the Statue of Liberty.max file from the Chap 22 directory on the DVD.

    This file contains a simple balloon mesh and a background image of the Statue of Liberty. I also created in Adobe Photoshop a simple image with four horizontally striped colors to apply as a map to the balloon. Another preparation step was to create a mask for the Statue of Liberty. To do so, I loaded the Statue of Liberty image into a drawing program like Adobe Illustrator and used the Auto-Trace tool to convert the outline of the statue to splines. I saved the traced image as an AI file called Statue of Liberty Mask and imported the AI file into Max, where I created an extruded spline with the same shape as the background statue.

  2. Open the Material Editor by pressing the M keyboard shortcut. Select the first sample slot, and name the material Balloon Fabric. Then click the map button to the right of the Diffuse color swatch. In the Material/Map Browser, double-click the Bitmap selection. A File dialog box loads. Locate the image named image from book Balloon Stripes.tif, and click the Open button. After loading the bitmap, enter 75 as the W Angle in the Coordinates rollout to apply the map at an angle. Drag the sample slot to the balloon to apply the map. Use the Show Map in Viewport button to see the applied results.

  3. Use the Zoom and Pan tools to align the mask object on top of the background image so it covers the statue.

  4. With the mask object in place, open the Material Editor and select the second sample slot. Name the slot Statue of Liberty Matte, and click the Type button. Select the matte/shadow material by double-clicking it. Then apply it to the mask object.

  5. Position the balloon in the viewport so it covers the Statue of Liberty in the Perspective view. Make sure that the balloon is behind the mask object.

  6. To see the final result, you need to render the image. To do this, select Rendering image from book Render (or press F10) to open the Render Scene dialog box. Click the Render button at the bottom of the dialog box, and the image is rendered in the Rendered Frame Window.

Figure 22.6 shows the resulting rendered image.

image from book
Figure 22.6: A rendered balloon object behind an object with a matte/shadow material applied




3ds Max 9 Bible
3ds Max 9 Bible
ISBN: 0470100893
EAN: 2147483647
Year: 2007
Pages: 383

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