I'm a big fan of the light attenuation in UDK. Traditionally I've always used the constant-linear-quadratic falloff function to control how "soft" the falloff is, which gives three values to play with. In UDK you can get similar results, but you only need to tweak one value: FalloffExponent.

taken from the UDK lighting reference

I'm interested in what the actual mathematical function here is. The UDK lighting reference describes it as follows:

FalloffExponent: This allows you to modify the falloff of a light. The default falloff is 2. The smaller the number, the sharper the falloff and the more the brightness is maintained until the radius is reached.

Does anyone know what it's doing behind the scenes?

  • 2
    \$\begingroup\$ You actually need to know the function that UDK uses? Or are you actually interested in something that creates the same result? \$\endgroup\$
    – House
    Oct 29, 2013 at 15:00

1 Answer 1


The default equation for attenuation

f(x) = 1/( distance ^(exponent) )

from the images doesn't seem UDK is doing anything differently.

  • 1
    \$\begingroup\$ The down voter care to explain? Nope as usual. \$\endgroup\$
    – concept3d
    Nov 27, 2014 at 8:51

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