A scene by Pawel Filip lit by the physical atmosphere simulator.
Main properties of the physical sky lighting.
The Physical sky rollout allows you to enable the physical atmosphere lighting simulation to illuminate the scene.
|Enable||Turn the physical sky simulation ON||This can be used without the Sun option and will render the sky only|
|Latitude||Lets you define a precise location on earth by providing latitude coordinates||Some websites or map applications provides the coordinates with inverted plus and minus signs, if your settings does not match the real location, try to flip the value's sign|
|Longitude||Lets you define a precise location on earth by providing longitude coordinates||Some websites or map applications provides the coordinates with inverted plus and minus signs, if your settings does not match the real location, try to flip the value's sign|
|Heading||Lets you change the north direction, to match a wrongly oriented scene||The valid range is -180° to 180°|
The earth rollout allows you to edit accurately the position of the scene on earth. This is particularly useful when the scene is not oriented correctly and must be lit by daylight exactly as it will be in the real world.
Physical sun settings.
This rollout gives you the ability to use a physical sun emitter to light the scene.
|Enable||Activates the Sun lighting simulation||-|
|Year||Lets you define a specific year at which the sun astral position must be simulated||The valid range is 1971 to 2050|
|Month||Lets you define a specific month of the year at which the sun astral position must be simulated||The valid range is 1 to 12, matching one of the year's month|
|Day||Lets you define a specific day of the month at which the sun astral position must be simulated||The valid range is 1 to 31, matching one of the month's day|
|GMT||Lets you pick a specific time zone on earth to compensate for local daylight saving times||The default is the Greenwhich parallel with no time shift|
|Hour||Lets you pick a specific hour of the day at which the sun astral position must be simulated||The valid range is 0 to 23. Note that the physical atmosphere does not simulate night sky. At night times, the render will be pitch black|
|Minute||Lets you pick a specific minute of the hour at which the sun astral position must be simulated||The valid range is 0 to 59|
Sun overrides settings.
This rollout gives access to some physical sun overrides to control the sun ball power, color, position or diameter in order to accommodate to different situations, even unrealistic ones.
|Power||Lets you override the physically-correct sunlight power to raise or lower it||The unit is a percent of the physically-correct sun power|
|Use Kelvin||Enables the sun color customization.||This works in kelvin temperature, the valid range is 2500-10000. Default is 5777.|
|Temperature||Lets you override the physically-correct sunlight color temperature to use a custom one||Use carefully to avoid un-realistic results, unless it's the desired effect|
|Use position||Lets you override the sun object position by using user-friendly azimuth and altitude angles||The first setting is the azimuth (the sun's direction), while the second is the altitude (the sun's elevation above the horizon)|
|Azimut||Controls the sun's azimut (its position around the scene).||The valid range is -360°/+360°|
|Altitude||Controls the sun's altitude||The valid range is 0°/90°|
|Diameter||Lets you override the physically-correct sun diameter by using a custom setting||Used with care, it will immensely help the convergence of difficult sun caustics, particularly with the Metropolis sampler. Be aware the too large values will produce very soft sun shadows and un-realistic results. Although, combined with a lower sun power override, it can be used to mimic a fuzzy sky daylight. The valid range is 0.1 to 45°|
Various sun diameter settings and their effect on the render.
Physical atmosphere settings.
This simulate the various kind of impurities that may be floating in the atmosphere and affect the overall sun and sky shades and intensity.
|Turbidity||This simulates the haziness of the physical atomosphere||High values will produce a stronger atmosphere scattering, making the sun look dimmer and the sky brighter, with a yellow-ish tint|
|Aerosol||This simulates the amount of green-house gases present in the atomsphere||High values will produce a more orange/pink sun light color by simulating the scattering of the sun light through gases|