This light is like a bare light bulb hanging from the ceiling - it radiates…
Vectorworks Tip 361 – Light Falloff
As you move away from a light source the intensity of the light falls off. The actual amount that falls off is another physics concept known as the inverse square law. In simple terms as you double the distance from the light, the intensity of the light goes down by the square of the distance. For more information check out the manual 1601 Outdoor Lighting.