private ["_x1","_y1","_x2","_y2","_dist3D","_dist2D","_var1","_var2"];

_x1 = getpos (_this select 0) select 0;
_y1 = getpos (_this select 0) select 1;
_x2 = getpos nothing select 0;
_y2 = getpos nothing select 1;

_dist3D = nothing distance (_this select 0);
_dist2D = sqrt (  (_x2 - _x1)^2 + (_y2 - _y1)^2    );

_var1 = _dist3D - _dist2D;






_x1 = getpos (_this select 1) select 0;
_y1 = getpos (_this select 1) select 1;
_x2 = getpos nothing select 0;
_y2 = getpos nothing select 1;

_dist3D = nothing distance (_this select 1);
_dist2D = sqrt (  (_x2 - _x1)^2 + (_y2 - _y1)^2    );

_var2 = _dist3D - _dist2D;



_var1 - _var2