Create panel > Systems > Sunlight button and Daylight button
Create menu > Lights > Daylight System and Sunlight System
Create menu > Systems > Daylight System and Sunlight 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:
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Sunlight uses a directional light.
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Daylight combines Sunlight and Skylight. The Sunlight component can be an IES Sun light, an mr Sun light, or a standard light (a target direct light). The Skylight component can be an IES Sky light, an mr Sky light, or a Skylight.
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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 with exposure control.
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The mr Sun and mr Sky lights are also photometric, but are intended for use with the mental ray Sun & Sky solution.
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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).
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Note: When you create a sunlight system or a daylight system that uses a target direct light for the sun, the directional light's hotspot is set to encompass all geometry in the scene, so that shadows will render correctly. Specifically, the diameter of the hotspot is set to 65 per cent of the longest diagonal length of the scene extents.
To create a Sunlight or Daylight system:
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On the Create panel, click Systems and then click Sunlight or Daylight.
Alternatively, you can create a Daylight system from the Create menu > Lights or Systems submenu.
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Choose a viewport in which to create a compass rose (the compass direction of your "world"). This should be a Top or Perspective/Camera view.
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Drag to create the radius of a compass rose (the radius is for display purposes only), and then release the mouse button and move the mouse to set the orbital scale of the sun light over the compass rose. This can be any distance you find convenient, since directional and IES Sun lights produce parallel illumination regardless of where their icon is located. Click to finish.
Upon creation you have two objects in your scene:
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The compass rose, which is a helper object that provides the world direction for your sun.
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The light itself, which is a child of the compass rose, and is permanently targeted on the center of the compass rose.
If you created a Daylight system, the Daylight Parameters rollout on the Modify panel lets you choose the type of sunlight and skylight. The Sunlight drop-down list lets you choose IES Sun, mr Sun, or Standard (directional). The Skylight drop-down list lets you choose IES Sky, mr Sky, or Skylight. These lists also offer you the options of choosing no sunlight or no skylight.
Controls for the geographic location and time of day are on the Motion panel. The default time is noon, and the default date and time zone are based on your computer's local settings. The default location is San Francisco, CA.
The directional light created by the system is managed by two special controllers: Solar Date and Solar Time. After you create your system, you can access its creation parameters (time and date, location, orbital scale, and location) in the Motion panel for the directional light. The parameters are interrelated, so you can adjust them in any order. Generally, it's easiest to choose a location first, and then adjust the date and time. You can access the parameters for selected sunlight or skylight objects in the Modify panel. The radius of the compass rose is also editable from the Modify panel, after selecting the compass rose object.
If Date/Time position is selected the Sun and Sky multipliers are automatically set and animated according to their position. They can be edited only by using the Manual Position override.
Tip: Use Exposure Control with Daylight if your scene rendering is too bright or too dark.
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Example: To create a shadow study:
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On the Modify panel, set the date and Location.
Note: Once the Daylight system has been created, you can find these controls on the Motion panel.
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In the Control Parameters Time group, adjust the Hours spinner to a start time in early morning.
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For a complete view of your environment and its shadows, render an animation from a Top viewport or a view above your scene.
The Daylight Parameters rollout lets you define the daylight system's sun object. You can set the sunlight and skylight behaviors.
This rollout appears on the Modify panel when the light component of the Daylight system is selected.
Sunlight—Select one of three options for sunlight in your scene:
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IES Sun—Uses an IES Sun object to simulate the sun.
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mr Sun—Uses the mr Sun light to simulate the sun.
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Standard—Uses a Target Direct light to simulate the sun.
This rollout appears on the Create panel, and on the Motion panel when the light component of the Daylight or Sunlight system is selected.
Manual Override (Daylight system only)—When on, you can manually adjust the location of the sun object in your scene, as well as the intensity value of the sun object.
Azimuth/Altitude—Displays the azimuth and altitude of the sun. Azimuth is the compass direction of the sun in degrees (North=0, East=90). Altitude is the height of the sun above the horizon in degrees (Sunrise or Sunset=0).
Provides settings for the time, date, and time zone.
If the location you choose uses Daylight Savings Time, turn on the Daylight Saving Time checkbox. The Sunlight system adjusts the sun's azimuth and altitude accordingly during the summer months.
Hours/Mins/Secs—Specify the time of day.
Month/Day/Year—Specify the date.
Time Zone—Time zones range from –12 to 12. If you're uncertain about a time zone, you can look them up in Window's Date > Time Properties dialog (available through My Computer > Control Panel > Date > Time). Click the Time Zone tab, and then display the list of world locations and their time zones.
Daylight Savings Time—When on, calculates daylight savings by adjusting azimuth and altitude during the summer months.
Provides controls for setting the location of your scene in the world.
Get Location—Displays the Geographic Location dialog, which lets you set the latitude and longitude values by selecting a location from a map or a list of cities.
Note: For precise locations, enter exact coordinates using Latitude/Longitude.
[city name text box]—Displays the name of the city you choose from the Geographic Location dialog. If you adjust the Latitude or Longitude spinners after choosing a location, this area becomes blank.
Latitude/Longitude—Specify the location based on the latitude and longitude.
Orbital Scale—Sets the distance of the sun (the directional light) from the compass rose. Because a directional light casts parallel beams, this distance has no effect on the accuracy of the sunlight. However, the light must point toward your model (not away from it), and the light's hotspot and falloff do have an effect.
The best way to ensure that the light is set up correctly is to change one viewport to the light's view (for example, Sun 01). Then adjust the light's location using Dolly, and set the hotspot so it illuminates the whole model, with no falloff.
North Direction—Sets the rotational direction of the compass rose in the scene. This is the geographical orientation of the compass rose. By default, north is 0 and points along the positive Y axis of the ground plane. Positive X (East) is 90 degrees. Adjust the North Direction to correspond to your site. Accuracy of the system depends on this correspondence.