2011

Table Of Contents
Set the Type of Lighting
AutoCAD for Mac offers three choices for lighting units: standard (generic),
International (SI), and American. The standard (generic) lighting workflow is
equivalent to the lighting workflow in AutoCAD for Mac prior to AutoCAD
2008. The default lighting workflow for drawings created in AutoCAD 2008
and later is a photometric workflow based on International (SI) lighting units.
This choice results in physically correct lighting. The American lighting unit
provides another option. American differs from International in that
illuminance values are formatted in foot-candles rather than lux.
In previous versions of AutoCAD for Mac, standard lighting was the default.
You can change the type of lighting with the LIGHTINGUNITS system variable.
The LIGHTINGUNITS system variable set to 0 represents standard (generic)
lighting; set to 1 represents photometric lighting in American units; set to 2
represents photometric lighting in International SI units.
Photometric Lights
Photometric lights are physically correct lights. Physically correct lights
attenuate as the square of the distance.
You can create lights with various distribution and color characteristics, or
import specific photometric files available from lighting manufacturers.
Photometric lights always attenuate using an inverse-square falloff, and rely
on your scene to use realistic units.
Tone Mapping
Generally with photometric lights and especially the sun you need to perform
tone mapping. Tone mapping can be adjusted with the RENDEREXPOSURE
command. The Adjust Rendered Exposure dialog box provides a preview and
controls to adjust the tone mapping.
Quick Reference
System Variables
LINEARBRIGHTNESS
Controls the brightness level of the viewport when using default lighting or
generic lights.
LINEARCONTRAST
Controls the contrast level of the viewport when using default lighting or
generic lights.
Standard and Photometric Lighting Workflow | 959