Invisible – When enabled, the shape of the light source is not visible in the render result. When disabled, the source is rendered in the current light color. This only affects the visibility of the light when seen directly by the camera or through refractions. The visibility of the light with respect to reflections is controlled by the Affect Specular option.
No Decay – The – The light intensity is inversely proportional to the square of the distance from the light (surfaces that are farther from the light source receive less light than surfaces which are closer to the light). When this option is enabled the intensity does not decay with distance.
Shadows – When enabled (the default), the light casts shadows. When disabled, the light does not cast shadows.
Affect Diffuse – When enabled, the light affects the diffuse properties of the materials.
Affect Specular – When enabled, the light affects the specular of the materials.
Affect Reflections – When enabled, the light appears in the reflections of materials.
Affect Atmospherics – Specifies whether the light influences the atmospheric effects in the scene. The value determines the amount of involvement.
Caustic Subdivs – Used by V-Ray when calculating Caustics. Lower values produce noisy results but render faster. Higher values produce smoother results but take more time.
