When you render the scene in 3D Studio MAX ( 3ds max ), you would notice that the lights intensity doesn't decrease with distance. In order to make the scene look more realistic in 3D Studio MAX ( 3ds max ), we need to turn Attenuation on. Attenuation causes the lights intensity to fall off with distance. Objects that are closer to the light receives more light, whereas farther objects receives only less.

With the omni selected in the scene, within the modify panel, within Decay, change the Decay Type to Inverse Square. This causes the light's intensity to fall down logarithmically with distance in 3D Studio MAX ( 3ds max ). Now you would notice a circlular boundary shown in the viewports around the Omni for which we turned decay on. This boundary in 3D Studio MAX ( 3ds max ) shows the limit beyond, which the light starts to fall off. Change the Start value to 100. This increases the circular boundary.

Once you turn decay on in 3D Studio MAX ( 3ds max ) , you will have to increase the multiplier value of the light, or the scene will be under-illuminated. Increase the Multiplier value to 5. Render the scene to see the effect of decay.

You can customise the effect of decay by specifying the near and far attenuation values. in 3D Studio MAX ( 3ds max ). Change the Far Attenuation value as: Start: 80, End: 400. Now enable the Use checkbox to enable the attenuation. This creates a larger circular boundary around the omni that shows the area beyond which far attenuation occurs. Render the scene to see the effect. The values we have given in 3D Studio MAX ( 3ds max ) are simply experimental. Try entering different values to see the variations in far range attenuation. You may also experiment with the near attenuation.