The coordinate along the X axis of the currently selected control point. The X coordinate is measured as a percentage of the attenuation max distance; therefore, the value will always fall between 0 and +/- 100, regardless of the actual distance value (which could even be 0).
If more than one control point is selected, the field displays a value of 0. This way, you can increase or decrease the value of all selected control points relative to their current values. For example, if you select two control points and type -5 in the X text box, both control points will move to the left by 5 percentage units.
Default value: 0
Range: -100 to 100