Spectron is a procedural lighting system for OctaneRender® that lets you create procedurally driven volumetric lighting, such as spotlights, with blockers, barn doors and gels (color). Spectron leverages the speed of AI to illuminate the scene quickly and with less noise than the original mesh-based lights that Octane otherwise employs. Currently, this option is available only to Octane Arealights and only when Arealights are set to an Area Shape of either rectangle or sphere (OctaneLight > Details tab > Area Shape...). Before Spectron's procedurally defined light emitters, Octane could use only mesh emitters, and Area lights were converted on the fly to geometry emitters. More Spectron-enabled lights will come as Octane moves forward.


To enable Spectron, the Use Primitives option needs to be enabled in the Light settings tab of the Octane Light tag. Additionally the AI Light option must also be enabled, as shown here.


spectron light


Spectron Area/Sphere Primitives

Two default light primitives have been added to the Octane lighting offerings. To enable Spectron, see the section above:


    • Spectron area primitive
    • Spectron sphere primitive


Spectron offers an improved the light sampling algorithm for these light primitives, considering the subtended solid angle of the receiving mesh surface. This will allow for improvement in noise reduction for direct light sampling and will generally improve convergence of the image at a faster rate versus the usage of traditional mesh light sampling.


Here is a comparison of a sphere mesh emitter vs the Spectron sphere light.



Another look at the mesh quad emitter:



Another look at the new Spectron area light:



The following image shows the effect on the noise of the image using spectron area light versus traditional mesh light (at 1 sample per pixel) 



Spectron area light vs traditional mesh light (10 samples per pixel):



and Spectron area light vs traditional mesh light (20 samples per pixel):



The following three images show the effect on the noise of the image using Spectron sphere light versus traditional mesh light (at 1 sample per pixel, 10 samples per pixel, and 20 samples per pixel):