Copyright Goodheart-Willcox Co., Inc. Chapter 17 Materials in AutoCAD 469 Noise A noise map is a 3D map based on a random pattern of two colors used to create an uneven appearance on the material. It is most often used to simulate materials such as concrete, soil, asphalt, grass, and so on. When you specify Noise as the map for a property, the texture editor displays the properties for the map, Figure 17-31. The properties in the Appearance area control how the noise looks. First, you need to select the type of noise. The options for the Noise Type property are: • Regular. This is “plain” noise and useful for most applications. • Fractal. This creates the noise pattern using a fractal algorithm. When this is selected, the Levels property in the Noise Threshold category is enabled. • Turbulence. This is similar to fractal noise, except that it creates fault lines. The Size property controls the size scale of the noise. The larger the value, the larger the size of the noise. The value can range from 0.00 to 1 billion. The Color 1 and Color 2 properties control the color of the pattern of noise. You can assign a color, image, or texture to the property. To swap the color defi nitions, pick the button next to the prop- erties and select Swap Colors from the drop-down list. The properties in the Noise Threshold category are used to fi ne-tune the noise effect. The properties in this category are: • Low. The closer this setting is to 1.00, the more dominant color 1 is. The default setting is 0.00 and it can range from 0.00 to 1.00. • High. The closer this setting is to 0.00, the more dominant color 2 is. The default setting is 1.00 and it can range from 0.00 to 1.00. • Levels. Sets the energy amount for the fractal and turbulence types. Lower values make the fractal noise appear blurry and the turbulence lines more defi ned. The default setting is 3.00 and it can range from 1.00 upward. • Phase. Randomly changes the noise pattern with each value. This allows you to have materials with the same noise map settings look slightly different. You should have different patterns on different materials. This adds a level of realism to your scene. Set the type of noise Set the noise size Set the colors Define the noise threshold Define the map position Figure 17-31. Adjusting the properties of a noise map.