2012

Table Of Contents
RENDERUSERLIGHTS
Controls whether to override the setting for viewport lighting during
rendering.
SUNSTATUS
Turns on and off the lighting effects of the sun in the current viewport.
Sun and Sky Simulation
The sun is a light that simulates the effect of sunlight and can be used to show
how the shadows cast by a structure affect the surrounding area.
Sun and sky are the primary sources of natural illumination in AutoCAD.
Whereas the rays of the sun are parallel and of a yellowish hue, the light cast
from the atmosphere comes from all directions and is distinctly bluish in
color. When the LIGHTINGUNITS system variable is set to photometric, more
sun properties are available.
When the workflow is photometric (the LIGHTINGUNITS system variable is
set to 1 or 2) the sun properties have more properties available and are rendered
using a more physically accurate sunlight model. The sun color is disabled for
the photometric sun; the color is computed automatically based on the time,
date, and location specified in the drawing. The color is determined based on
the position in the sky. When the workflow is generic or standard lighting
(the LIGHTINGUNITS system variable is set to 0), the additional sun and sky
properties are unavailable.
The properties of the sun can be modified by using the SUNPROPERTIES
command. The Sun Properties window is displayed. The details of the settings
are located under SUNPROPERTIES in the Command Reference.
The rays of the sun are parallel and have the same intensity at any distance.
Shadows can be on or off. To improve performance, turn off shadows when
you dont need them. All settings for the sun except geographic location are
saved per viewport, not per drawing. Geographic location is saved per drawing.
The angle of the light from the sun is controlled by the geographic location
you specify for your model and by the date and time of day. These are
properties of the sun and can be changed in the Sun Properties window and
the Geographic Location dialog box. The time zone used is based on the
location, but you can adjust it independently (TIMEZONE system variable).
2194 | Chapter 44 Add Lighting to Your Model