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characteristics, or import specific photometric files available from lighting
manufacturers.
Photometric lights can use manufacturers' IES standard file format. By using
manufacturers’ lighting data, you can visualize commercially available lighting
in your model. Then you can experiment with different fixtures, and by varying
the light intensity and color temperature, you can design a lighting system
that produces the results you want.
Sun and Sky
The sun is a special light similar to a distant light. The angle of the sun is
defined by the geographic location that you specify for the model and by the
date and time of day that you specify. You can change the intensity of the
sun and the color of its light. The sun and sky are the primary sources of
natural illumination. With the
sun and sky simulation (page 735), you can
adjust their properties.
In the photometric workflow, the sun follows a more physically accurate
lighting model in both the viewport and the rendered output. In the
photometric workflow, you can also enable sky illumination (through the sky
background feature), which adds soft, subtle lighting effects caused by the
lighting interactions between the sun and the atmosphere.
Luminaire Objects
Light fixtures can be represented by embedding photometric lights in blocks
that also contain geometry. A luminary assembles a set of light objects into a
light fixture.
714 | Chapter 13 Render Drawings