Spotlight
The Spotlight () acts like a flashlight and has both a position and a direction. To add a Spotlight node:
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In the Model Builder, under Definitions click View. In the View toolbar, click Spotlight, or
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Right-click the View node and select Spotlight.
Figure 6-25 is an example of two Spotlight nodes added to a View with all other nodes disabled. You can adjust the position and direction of the light, the light and specular intensity levels, and the color as needed. In addition, the spread angle can be adjusted as shown in the figure. The width of the light marker corresponds to the spread angle.
Figure 6-25: Two Spotlight nodes displayed with all other nodes disabled showing where the Spotlight is focused. When the spread angle is changed from 20 to 100 for Spotlight 7 (as indicated by the change in marker width between 7 and 7a), a corresponding change is made to the model.
Position
Enter x, y, and z coordinates for the position of the spotlight.
Direction
The x, y, and z coordinates define the direction in which the spotlight falls on the objects in the scene. The arrow points in the direction of the light.
Change the color to something other than white to observe where the light hits the object.
Settings
Adjust some of the settings such as the spread, intensity, and color of the spotlight.
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Enter a Spread angle (in degrees). Also watch the changes in the Graphics window at the same time to help choose an angle. When adjusting the spread angle, the arrow increases and decreases in width as the angle value increases and decreases. The default is 20 degrees. See Figure 6-25 for an example.
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Enter a Light Intensity or use the slider to select values. Watch the changes in the Graphics window at the same time to help choose a level. The light marker’s length changes as the corresponding light intensity changes.
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Enter a Specular intensity (the intensity of the light that reflects off the surface of the geometry and used to define spheres and curves). You can turn specular light on and off in the Settings window for View (default: on), and the levels are adjusted for each Specular intensity using the field or the slider to select values between 0 and 1 (default value: 1). Watch the changes in the Graphics window at the same time to help choose a level. See Figure 6-21 for an example of specular light.
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Select a Color: White (default), Custom, Black, Blue, Cyan, Green, Magenta, Red, or Yellow. If you select Custom, click the Color button to choose a color from the Custom color palette.
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By default, the Lock to camera coordinate system check box is selected to make the light rotate together with the camera. Click to clear as needed; the light then follows the geometry.
To lock the camera settings, see Camera.
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By default, the Show light marker is selected. The light marker is associated to the type of light applied to the object. See Figure 6-22 for examples. Click to clear the check box as needed and remove the marker from the Graphics window.
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By default, the Cast light and Cast shadows check boxes are selected. The spotlight will then cast shadows when the direct shadows are active (requires the OpenGL renderer, optimized for quality). Clear the Cast shadows check box if you do not want the light to cast shadows.
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The Cast shadows of floor check box is cleared by default. Select it to get the shadows from this light source to show up on the floor.
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Enter positive values in the Angle attenuation scale (default: 0.2) and Distance attenuation scale (default: 0.001) fields to control the gradual fade out of light at an angle away from the spotlight direction and a weaker light intensity farther away from the spotlight, respectively. The angle attenuation increases when its scale factor is lower, whereas the distance attenuation decreases when its scale factor is lower. Scale factors above 1 have an effect, but the differences can be subtle.