Copyright Goodheart-Willcox Co., Inc. Chapter 18 Lighting 495 The falloff, not to be confused with attenuation, is the outer cone of illumination for a spotlight. Like the hotspot, it is measured in degrees. The falloff value must be greater than or equal to the hotspot value. It cannot be less than the hotspot value. In practice, the falloff value is often much greater than the hotspot value. To set the falloff, enter the Falloff option and then specify the number of degrees for the falloff. NOTE NOTE The Shadow and Attenuation options are only available for backward compatibility with older releases of AutoCAD. Shadow casting cannot be turned off and shadow- mapped shadows are created by AutoCAD, as previously discussed. Inverse square attenuation is used regardless of the attenuation type selected. Setting the attenuation start and end limits has no effect on the scene. Once the light is created and you select it in the viewport, grips are displayed. If you hover the cursor over a grip, a tooltip is displayed indicating what the grip will modify. You can use grips to change the location of the spotlight and its target, the hotspot, and the falloff. If you hover over a falloff or hotspot grip, the current angle is displayed in the wireframe cone (if dynamic input is on). Free Spotlight A free spotlight is like a standard spotlight except that you do not specify a target, only the light location. The rest of the options are the same. You can type FREESPOT or pick the Freespot option in the LIGHT command to create a free spotlight. When created, a free spotlight points down the Z axis (from positive to negative) of the current UCS. A free spotlight may be easier to control than a standard spotlight because you do not have to worry about the target point. If you want to change the angle or position of the light, use the 3DMOVE and ROTATE3D commands. PROFESSIONAL TIP PROFESSIONAL TIP The best way to see how colored lights affect your model is to experiment. Remember, you can render selected areas of the scene. This allows you to see how changes to light intensity and color affect objects without performing a full render. Exercise 18-4 www.g-wlearning.com/CAD/ Complete the exercise on the companion website. FREESPOT Type FREESPOT LIGHT Object Figure 18-15. Hotspot and falloff for a spotlight are angular measurements.