496
AutoCAD and Its Applications—Advanced
Copyright Goodheart-Willcox Co., Inc.
Notice the button in the title bar of the
Sky Properties
category. Picking this button
opens the
Adjust Sun & Sky Background
dialog box. This dialog box contains the same
settings found in the
Sun Properties
palette, but includes a preview of the sun and sky.
Use this dialog box to preview
Intensity Factor
and
Haze
property changes.
The settings in the
Horizon
subcategory control what the horizon looks like and where
it is located. Changing the
Height
property moves the horizon up or down. The default value
is 0.0000 and values can range from –10.0000 to 10.0000. The
Blur
property determines how
much the horizon is blurred between the ground and the sky. The default value is 0.1000
and values can range from 0.0000 to 10.0000. The
Ground color
property controls the color of
the ground. The default color is true color 128,128,128, which is a medium gray. To see how
this affects your scene, rotate your viewpoint to make the horizon visible.
The settings in the
Advanced
subcategory allow you to control some of the more
artistic settings of your scene. The
Night color
property sets the color of the night sky.
This is only visible if sky illumination is turned on. In a city, the night sky may have
an orange tint to it because of the streetlamps in the city. However, in the country, the
night sky is nearly black due to the lack of artifi cial illumination. The
Aerial perspective
property determines whether aerial perspective is applied. This is a way of simulating
distance between the camera and the sky/background. The property can be set to on
or off. Aerial perspective is controlled by the
Visibility distance
property. This sets the
distance from the camera at which haze obscures 10% of the objects in the background.
This is a very useful tool for creating the illusion of depth in a scene. The default value is
10000.0000, but the value can range from 0.0000 to whatever is needed. See Figure 17-10.
A
Visibility distance
setting = 100
Visibility distance
setting = 1000
B
Visibility distance
setting = 10
C
Figure 17-10.
In this scene, the red box is about 15 units from the viewer, the yellow cylinder is 200 units
away, and the blue cone is 250 units away. Notice how the lower
Visibility distance
settings
create the illusion of depth.