Chapter 23: Adding Material Details with Maps


In addition to using materials, another way to enhance an object is to use a map-but not a roadmap. In Max, maps are bitmaps, with patterns that can be applied to the surface of an object. Some maps wrap an image onto objects, but others, such as displacement and bump maps, modify the surface based on the map's intensity. For example, you can use a diffuse map to add a label to a soup can or a bump map to add some texture to the surface of an orange.

Understanding Maps

To understand a material map, think of this example. Cut the label off of a soup can, scan it into the computer, and save the image as a bitmap. You can then create a cylinder with roughly the same dimensions as the can, load the scanned label image as a material map, and apply it to the cylinder object to simulate the original soup can.

Different map types

Different types of maps exist. Some maps wrap images about objects, while others define areas to be modified by comparing the intensity of the pixels in the map. An example of this is a bump map. A standard bump map would be a grayscale image-when mapped onto an object, lighter colored sections would be raised to a maximum of pure white, darker sections would be indented, and the black areas in the bitmap would be indented the furthest. This enables you to easily create surface textures, such as the rivets on the side of machine, without having to model them.

Still other uses for maps include background images called environment maps and projection maps that are used with lights.

CROSS-REF 

For information on environment maps, see Chapter 43, "Learning Rendering Basics." Chapter 27, "Using Lights and Basic Lighting Techniques," covers projection maps.

Maps that are used to create materials are all applied using the Material Editor. The Material/Map Browser provides access to all the available maps in several different categories. These maps have many common features.

Tip 

To see applied maps in the viewports, select the Show Map in Viewport button in the Material Editor or enable all scene maps with the Views image from book Activate All Maps menu command. But this can slow the display, so the Views image from book Deactivate All Maps menu command can be used to speed the display.

Using Real-World maps

When maps are applied to scene objects, they are applied based on the bitmap's resolution, so a 100 × 100-pixel bitmap would cover twice as much area as a 50 × 50-pixel bitmap. But, each bitmap can be sized along each axis to stretch the map over the surface. Another way to stretch a texture map is to resize the geometric object that the map is applied to. This is the default behavior of maps, but another option is available.

When a geometric object is created, you can enable the Real-World Map Size, which is generally next to the Generate Mapping Coords option. This option is also available when the UVW Mapping modifier is applied to an object. When enabled, this option lets you specify the size of the applied texture using scene units. When this option is enabled, it causes the texture maps to maintain their sizes as geometry objects are resized. Set the dimensions of applied texture maps in the Coordinates rollout.

Tip 

You can select to have Real-World mapping enabled for all new objects by default by enabling the Use Real-World Texture Coordinates option in the General panel of the Preference Settings dialog box.




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

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