View Full Version : Light Intensity Falloff

05-31-2004, 12:11 PM
ok, can someone please tell me if this is a bug or intentional? if this is how things are supposed to work, can someone explain why?

when i turn on Intensity Falloff for a light, the light becomes much brighter within the Range/Nominal Distance. so a light set at 100% Light Intensity seems like a 200% light when i turn on Intensity Falloff. this is not what i would expect to happen based on the documentation. i would think that the scene overall should appear dimmer when the light is using Intensity Falloff. only objects very close to the light should receive close to 100% light intensity, but instead, everything the light can reach is blown out.

also, i have noticed that a light with a Range/Nominal Distance set to a certain distance illuminates objects beyond that distance. according to the documentation, this is the distance where the light intensity fades to zero. this also seems contrary to the description of the feature.

it is very hard to balance the lighting in a scene with multiple lights when changing the Falloff increases the Intensity.

i have observed this with point lights and spotlights. can anyone tell me what's going on?

05-31-2004, 12:22 PM
It seems you use one of the inverse distance fall off's. Since the formula never gets to zero the light reaches even elements outside of the fall off distance. And i agree that the bright light with the fall off is irritating, seems that the formula was used a bit wrong in comparsion to no fall off.

05-31-2004, 03:01 PM
With Inverse distance, the falloff distance is the size of your light source, i.e. 50mm for a standard light bulb ~ it's where the light begins to fall off.

05-31-2004, 03:42 PM
ah... with the inverse falloffs, the Range/Nominal Distance is the range at which the intensity is equal to the Light Intensity for that Light Source. beyond that it simply falls off as an inverse or inverse squared function. this makes sense, but the interface could use some improvement. at least, the documentation could be updated to explain the different behavior between linear and inverse falloffs.

controls like those for fog would be more flexible.

thanks, toby and ingo.

05-31-2004, 04:05 PM
Yeah Ive been asking for controls like those in Fog to be implemented for Light falloffs. As well for Distance dissolve and some other distance-related things. Kinda sad its not in [8] already, but maybe next time.