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Many of the constants in the Unreal Engine have been tweaked to achieve good results for the current scale. As a result, deviating from this scale by a factor of 2 should be fairly straightforward, but deviating by a factor of 10 might have some subtle and hard to track down side effects. In general, Epic does not recommend changing the Unreal Unit scale by more than a factor of 2.
In all of the Unreal Tournament games, 1 Unreal Unit is equal to 2 cm. In Gears of War approximately 2 Unreal Units equal 1 inch, because the characters are 156 units tall and a floor of a building is 256 units tall. This was decided on for grid purposes and so our cover height worked out well. Most licensees use a scale of 1 Unreal Unit to 1 cm.
// 2 UU == 1" // <=> 1 UU == 0.0127 m #define AUDIO_DISTANCE_FACTOR ( 0.0127f )