Octane Standalone Documentation

The Daylight Environment system simulates an outdoor lighting setup using real-world parameters (figure 1). It can be accessed by right-clicking in the Node Graph Editor, then navigating to the Environments category, and then clicking on Daylight Environment (figure 2).

Figure 1: The Daylight system with varying sun positions

Figure 2: Create a Daylight environment node

Switching to the Daylight environment can be done in the Node Inspector for the current Render Target as well (figure 2):

Figure 3: Changing the environment to the Octane Daylight System

Daylight Environment Parameters

The Daylight Environment system uses sun direction as the method for controlling the direction of the lighting. 

• Longitude/Latitude - Get realistic sun settings for the specified geographic location.
• Month/Day/GMT Offset/Local Time - These parameters can accurately place the sun in the sky according to the date/time for the sun at the current longitude/latitude.
• Interactive Map - The map can set the scene's geographic location. The sun's position can be set by dragging the crosshairs around on the map (Figure 4).

Figure 4: An interactive map for sun position

Sky Turbidity - Adjusts the sunlight shadow's sharpness. Low values create sharp shadows similar to a sunny day, and higher values diffuse the shadows similar to a cloudy day.

Power - Adjusts the light's strength. This can affect the image's overall contrast and exposure levels.

Sun Intensity - Adjusts the scale factor for the sun and can be used to adjust the relative power of the sun compared to the sky.

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

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 Octane Daylight model to customize the spectral shade of light. This can affect overall mood expressed by the image.

Sun Size - Controls the sun radius in the environment.

Ground Color - Base color of the ground. Only works with the Octane, Nishita & Hosek Wilkie daylight models.

Ground Start Angle - The angle (in degrees) below the horizon where the transition to the ground color begins. This only works with the Octane daylight model.

Ground Blend Angle - The angle above which the sky color transitions to the ground color. This only works with the Octane daylight model.

Sky Texture - Connects a texture to use as the background, and ensures that objects in the scene accurately reflect it (figure 5).

Figure 5: An HDRI used as a Sky Texture

Importance Sampling - This toggles the Sky texture's importance sampling which enables quicker convergence (noise reduction) for HRDI images by applying importance to certain areas of the HDRI.

Visibility Cache - Enables adaptive environment light sampling that takes visibility into account.

Cast Photons - If photon mapping is used, this will cast photons from bright areas in the environment map.

Medium - This parameter accepts an Absorption, Scattering, or Volume medium node to create volume/fog effects across the scene. For more information, see the Volume Fog Effects topic under the Effects category in this manual.

Medium Radius - Adjusts the medium's scale.

Medium Light Pass mask - Enables or disables lights on the scattering environment medium.

Use in Post Volume - Enables or disables the light in post volume rendering.

Trace Sets 

The Trace Set system allows for greater control over including or excluding scene data from object surfaces when light hits the surface.

Visible Environment

Nodes connected to the Environment pin on a Render Target node are considered the primary environment. Nodes connected to the Visible Environment pin on a Render Target node provide a way to separate the background, reflections and refractions from the primary environment. Both the Environment and the Visible Environment pins accept Daylight, Planetary, and Texture environment nodes. 

Backplate - Uses the environment specified in the Visible Environment node as the background.

Reflections - Uses the environment specified in the Visible Environment node as the scene object reflections.

Refractions - Uses the environment specified in the Visible Environment node as the scene object refractions.