In stage lighting there are several tools for shaping the directionality of the light. Barn doors, top hats. They can be characterized not only by an angle at which they can be opened, but also by the length of these shutter-like element, so probably there should be a parameter for shutter length, in addition to directionality (angle, spread). As you can see, on the screenshot, light shutter angle and length combined give pretty dramatical difference on penumbra light distribution. Emissive plane is hidden inside the light constraining meshes.
7 Likes