Copyright Goodheart-Willcox Co., Inc. 434 AutoCAD and Its Applications—Advanced Introduction to Lights Lights provide the illumination to a scene and are essential for rendering. There are three types of lighting in AutoCAD—default lighting, sunlight, and user-created lighting. AutoCAD automatically creates one or two default light sources in every scene. These lights ensure that all surfaces on the model are illuminated and visible. The types of lighting are discussed in more detail in Chapter 18. A scene can be rendered with the default lights, but the results are usually not adequate to produce a photorealistic image. Normally, user-created lighting or sunlight is added to the scene and adjusted to obtain the desired results. When a light is added to a scene, the default lights must be turned off. The fi rst time you add a light, you receive a warning to this effect (unless the warning has been disabled). In this section, you will learn how to add sunlight to the scene. Chapter 18 provides detailed information on lighting. Sunlight is produced by an automated distant light. Sunlight can be turned on by picking the Sun Status button in the Sun & Location panel on the Visualize tab of the ribbon. The button background is blue when sunlight is on. See Figure 16-17. If the Default Lighting button is on in the Lights panel when the Sun Status button is turned on, a warning dialog box is displayed. This dialog box gives you choices to either turn off default lighting or keep it on. You cannot see the effects of sunlight with default lighting turned on, so it is recommended to turn it off. Another warning dialog box is displayed informing you that sunlight requires a different exposure setting from other lights. Different types of lighting require different exposure settings and AutoCAD is recommending you to adjust the exposure settings before switching to sunlight. Exposure settings are discussed in Chapter 19. For now, choose to keep exposure settings the way they are. Once sunlight is turned on, you can make adjustments to visualize different effects of the sunlight settings on the objects in your scene. Shadows will display in the viewport only if the current visual style is set to display shadows or if shadows are turned on by selecting one of the options in the shadows fl yout in the Lights panel in the Visualize tab of the ribbon. Full shadows will be shown in the rendering. The Date and Time sliders in the Sun & Location panel on the Visualize tab of the ribbon are active when sunlight is turned on. You can drag the sliders to adjust the date and time. The current date and time are displayed on the right-hand end of the sliders. As you drag the sliders, the lighting and shadows in the scene change to refl ect the settings. SUNSTATUS Ribbon Visualize Sun & Location Sun Status Type SUNSTATUS Default lighting is off Blue background indicates sunlight is on Current date Current time A B Figure 16-17. The Lights and Sun & Location panels on the Visualize tab of the ribbon. A—Turn off default lighting to see the effects of sunlight in the scene. B—Use the Date and Time sliders in the Sun & Location panel to adjust the date and time.