The Perez All-Weather sky model is a physically accurate sky model recognized as an industry standard. It is controlled by two illuminance values.
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Create a Daylight system. > Choose mr Sky as the sky light. > Choose Perez All Weather as the sky model. > mr Sky: Perez Parameters rollout
Note: The Perez model is suitable for daytime, but not for twilight or night scenes. For scenes where the sun is low or absent, use the Haze model, or the CIE model if you are concerned with photometric accuracy.
When you render while the Perez sky model is active, the sky color derives from the Haze value in the mr Physical Sky shader. By default this is 0.0 (a clear sky, blue in the daytime), but you can use the shader to change the Haze value.
Interface
- Diffuse Horizontal Illuminance
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The illuminance of the sky measured by a luminance meter placed horizontally, outdoors, excluding the contribution from the sun. Default=10000.0 lx.
You can animate this value.
- Direct Normal Illuminance
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The illuminance of the sun measured by a luminance meter aimed directly at the sun. Default=10000.0 lx.
You can animate this value.
Note: If you have chosen American units as the active lighting units, the illuminance values appear as footcandles (fc) rather than lux (lx).