2009

Create menu > Lights > Daylight System
Create menu > Systems > Daylight System
The Sunlight and Daylight systems use light in a system that follows the
geographically correct angle and movement of the sun over the earth at a
given location. You can choose location, date, time, and compass orientation.
You can also animate the date and time. This system is suitable for shadow
studies of proposed and existing structures. In addition, you can animate
Latitude, Longitude, North Direction, and Orbital Scale.
Sunlight and Daylight have a similar user interface. The difference is that:
■ Sunlight uses a
directional light on page 5060.
■ Daylight combines Sunlight on page 8140 and Skylight on page 8129. The
Sunlight component can be an
IES Sun light on page 5154, an mr Sun light
on page 5173, or a standard light (a target direct light on page 5057). The
Skylight component can be an
IES Sky light on page 5157, an mr Sky light
on page 5176, or a Skylight on page 5065.
■ The IES Sun and IES Sky lights are photometric lights. It is appropriate
to use them if you are creating a rendering that uses
radiosity on page
6168 with
exposure control on page 6732.
■ The mr Sun and mr Sky lights are also photometric, but are intended
for use with the
mental ray Sun and Sky on page 5161 solution.
■ The Standard light and Skylight are not photometric. It is appropriate
to use them if your scene uses standard lighting (Sunlight with its
Directional light works for this, too), or if you are using light tracing
on page 6154.
When you first create a Daylight system, the default creation parameters are
set to midday (noon) on the summer solstice (June 21). Use the Get Location
button in the Control Parameters rollout (see below) to choose the correct
geographic location. If the rollout is not available, select the Daylight01 object
in the viewport to gain access.
NOTE When you create a Daylight system from the Create menu, a dialog appears
asking if you want to use the
Logarithmic Exposure Control on page 6740 if the
renderer is set to Default Scanline, or the
mr Photographic Exposure Control on
page 6744 if the renderer is set to mental ray. It is recommended that you click Yes
to enact this change.
5140 | Chapter 18 Lights and Cameras