Octane for Houdini

The Gradient environment creates lighting based on a gradient (figure 1). 

Figure 1: A scene rendered using the Gradient environment

The Gradient system is found in the Environment tab of the Render Target parameters window (Figure 2). The Gradient system can also be found in the Octane Render Setup node located in the Object window (figure 3).

Figure 2: Accessing the Gradient environment node from an Octane Render Target. 

Figure 3: Accessing the Gradient parameters in the Octane Render Setup node

Parameters specific to the Gradient system are found in the Intensity, Transform, Medium, and Options rollouts.There is a Backplate tab available to further control the options for displaying backplate elements (figure 4). If the Backplate is set to anything other than Disabled, such as Backplate Gradient,  the Backplate parameters will override any duplicate background elements available in the Gradient tab. Note that the Backplate parameters do not affect the physical lighting on scene objects. 

Figure 4: Accessing the Environment Backplate parameters

Gradient Environment Lighting Tab Parameters

Intensity Rollout

Power - Controls the brightness of the gradient light color. 

Gradient - Provides a gradient set of colors for the light color. 

Transform Rollout

Rotation - Rotate the gradient. 

Scale - Scales the gradient.

Translation - Moves the gradient. 

Offset - Offsets the gradient.

Medium Rollout

Offers control of a medium used to give aerial density and fog to the Gradient system. This is an actual volume medium effect, not a cheat. It interacts directly with any lighting in the scene.

Options Rollout

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. 

Backplate Gradient Tab Parameters

These parameters will override their conterparts in the Lighting tab. 

Intensity Rollout

Power - Controls the brightness of the gradient light color. 

Gradient - Provides a gradient set of colors for the light color. 

Type Rollout

Gradient Type - Determines the type of gradient generated.

Repetitions - Specifies the number of times the gradient is generated. 

Polygon Sides - Determines the number of polygons sides when the Polygonal gradient type is selected. 

Gamma - Set the gamma correction coefficient. 

Repetition Mode - Determines the gradient behavior when repeating. 

Invert - Inverts the output color. 

Transform Rollout

Rotation - Rotate the gradient. 

Scale - Scales the gradient.

Translation - Moves the gradient. 

Projection - Determines the direction the gradient is projected. 

Mode - Coordinate space used to compute the ray direction. 

View Direction - If checked, the resulting vector goes from the viewing position to the shaded point position. If not checked, the resulting vector goes in the opposite direction. 

Normalize Result - Determines whether to remap the result to the 0-1 range. 

Options Rollout

Backplate - Makes the Background Plate environment visible in the background.

Reflections - Makes the Background Plate environment visible in reflections..

Refractions - Makes the Background Plate environment visible in refractions.