Daylight

OctaneRender^® has a powerful Daylight environment system to simulate real-world illumination that consists of a primary light (sun), indirect light (sky/environment), and atmosphere. This is the default lighting system that is active when you create a Render Target node.

Figure 1: The Daylight Environment rendering using the default settings

The Daylight system is found in the Main tab of the Render Target parameters window (Figure 2).

Figure 2: Accessing the Daylight parameter from the Main tab of a Render Target node

Parameters specific to the Daylight system are found in the DL Environment tab in the Render Target's parameters (Figure 3).

Figure 3: The Daylight Environment parameters

Daylight (DL) Environment Parameters

Longitude/Latitude - Make realistic sun settings for a specified geographic location.

Month/Day/GMT Offset/Hour - Place the sun in the sky according to the date/time for the sun at the current longitude/latitude.

Sky Turbidity - The Turbidity can adjust the sharpness of the sun light's shadows. A low value creates sharp shadows like a sunny day, and a higher value diffuses the shadows like a cloudy day.

Power - Adjusts the light strength. This affects the image's overall contrast and exposure level.

Sun Intensity - The scale factor that is applied to the sun only. Use this to adjust the relative power of the sun compared to the sky.

North Offset - Adjusts the scene's North direction. This is useful for architecture visualization to ensure the sun's direction in the scene is accurate.

Daylight Model - Specifies the daylight model to use as the current environment.

Octane Daylight - This is the new default daylight model simulates full-spectrum daylight, providing more sky color variation as the sun moves along and bearing shorter rays as the sun moves closer to the normal plane.
Preetham Daylight - This is the old daylight model that lights a scene with basic spectral radiance as the sun moves over the horizon at a relative distance from the object.
Nishita Daylight - Implements atmospheric scattering based on the Nishita sky model and displays the color variations, which are optical effects caused by the particles in the atmosphere.
Hosek Wilkie Daylight - Produces more realistic and detailed results than other implementations specially in hazy conditions and near the horizon.

Sky Color/Sunset Color - These settings are used by the daylight model to customize the spectral shade of light. This can affect the scene's overall mood.

Sun Size - Controls the sun radius in the Daylight environment.

Ground Color - Base color of the ground which is an infinite plane that is only visible in the final rendering. It serves to produce a horizon line for the Daylight system. This allows the user to control the color of the infinite ground plane associated with the Sun Sky systems.

Ground Start Angle - The angle (in degrees) below the horizon where the transition to the ground color starts.

Ground Blend Angle - The angle over which the sky color transitions to the ground color.

Importance Sampling - This toggles the Sky texture's importance sampling, similar to the Texture environment's importance sampling.

Cast Photons - If photon mapping is used, this option casts photons from the bright areas of the scene.

Medium Radius - Adjusts the medium's scale.

Backplate - Generates a cutout rendering where foreground elements are positioned in the scene.

Reflections - Generates the Planetary environment in scene object reflections.

Refractions - Generates the Planetary environment in scene object refractions.

Enable Texture Environment - Activates another tab where you can load an HDRIAn image which presents more than 8 bit per color channel unlike most common image formats. texture map as a Sky texture.

Enable Environment Medium - Activates another tab where Medium parameters can produce atmospheric effects.

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