The Octane Light is the most basic type of light. When added to a Maya scene it appears as a yellow sphere. It casts light into the scene as a spherically shaped area light. Figure 1 shows how to create a light using the Create Render node window in Maya’s Hypershade.
Figure 1 : The Octane Light can be created by clicking on the button in the Create Render node window of Maya’s Hypershade.
Using the Geometry menu in the Light’s attributes, it can be switched to a planar area light (Figure 2). The quality of the light can be adjusted using the light’s parameters in the Attribute Editor. Figure 3 shows a scene lit by a planar style area light. Planar lights emit light from one side only. The Light’s transform uses a yellow arrow to indicate the direction the light leaves the surface.
Figure 2: The Geometry menu in the Light’s attribute editor can be used to switch the light from a sphere to a plane.
Figure 3: A scene is lit using a Plane shaped Octane light.
Octane Light Parameters
Is the wattage of the light source. Each light in the scene should be set to its real world wattage. For example, a desk lamp could be set to 25 watts.
Is the temperature (in K) of the light emission. Lower values result is a warmer light color, higher values create a cooler light color.
Is used to keep the luminance of the emitted light constant if the temperature varies.
Is used to determine how far the light is cast into the scene based on its power settings. No light is 100% efficient at delivering the power at the specified wattage (a 100 watt light bulb does not actually deliver 100 watts of light.) The efficiency setting can be used to enter the real world values. These values can be used to create very realistic light settings. For example, a standard 100 watt incandescent bulb would only be approximately 2.0% efficient whereas a 25 watt compact fluorescent light will be 10% efficient. These will both produce around the same quantity of light in real life.
Allows users to choose which light sources will receive more samples. The maximum sampling rate for an OctaneLight is 10,000. The sampling rate can also be set to 0 (zero), which means the emitter will be excluded from the direct light calculation.
Controls the visibility of the light emitter without affecting the illumination.
Can be set to Global, Scatter, Moveable Proxy and Shapeable Proxy. Typically this should be set to Global if the light is to remain stationary or Moveable Proxy if the light is going to be re positioned or animated.
Using IES Light Profiles
IES is a file format that contains the description of a light’s properties. Its typically used for simulating realistic architectural lights based on real world lights sold by vendors. IES profiles can easily be obtained on line by searching for IES light profiles. Many light manufacturers allow IES files to be downloaded for free.
To use an IES profile, download the desired file and place them in a folder on your local drive, the sourceimages folder of the current Maya project can be a convenient location for these files. Use the folder icon to the right of the IES profile slot to browse your computer’s file structure and locate the file location (Figure 4).
Figure 4: The IES settings in the Light’s Attribute Editor.
The rotation slider can be used to aim the light. Be aware that linking an IES profile light to a planar light shape will affect how the light is cast into the scene, it's usually best to make sure the light geometry is set to Sphere and not Plane. Aiming an IES light can be difficult, one trick that can make this easier is to parent or constrain the light to a cone primitive. Make sure the cone geometry is not visible in the render and does not cast shadows, then position and rotate the cone to aim the light.
Figure 5 shows a render of a number of IES light profiles. Note that the shadow shapes cast by the light are built into the IES light profile and represent the housing the manufacture creates for the lights.
Figure 5: IES Light profiles rendered in Octane for Maya
Video Tutorial: Octane Light Basics Part 1
Video Tutorial: Octane Light Basics Part 2