CIE Sky environment

Description

../../../_images/ciesky.jpg

Scene lit by a CIE sky type 12 environment

Environment The CIE sky environment correspond to the standard distributions defined in:

ISO 15469:2004 (CIE S 011/E:2003) - Spatial distribution of daylight - CIE standard general sky

Moon and Spencer (1942), Illumination from a non-uniform sky, Illum Eng., 37, 10, 707-726.

This environment describes only relative distribution of luminance across the sky. It does not provide neither absolute luminance nor spectral information. These can be user-defined by the zenith luminance parameter lz and the base spectrum child node.

By default, zenith is oriented towards (0,0,1). The environment orientation can be adjusted by modifying the zenith parameter.

Note

Using this feature requires an Lighting Edition license

Children Nodes

Spectrum base The environment spectral distribution

Parameters

name type description
sunpos vec3 The sun direction
zenith vec3 Zenith direction, allows for instance switching between Z-top and Y-top conventions
lz real The zenith luminance, in lux
skytype integer The sky type, can be ms for Moon & Spencer or t1 to t15 for CIE types

Ocean XML 4.0 example

<environment type="ciesky" name="cie" sunpos="0.707107 0 0.707107" zenith="0 0 1" lz="7500" skytype="t1">
     <spectrum type="preset" name="base" value="D65" gain="1"/>
</environment>