weaponDirection wrong elevation

[Frate 0]

Hello,
I'm trying to figure out if the player is aiming at an object.
I'm using weaponDirection but It does not point properly on elevation.
Seems to be following the terrain slope ahead.
How to solve this?
 

onEachFrame  
{  
_beg =  getpos player; 
_wDir = (player weaponDirection currentWeapon player vectorMultiply 100);
_endW = _beg vectorAdd _wDir;  
 drawLine3D [_beg, _endW, [0,1,0,1]];
drawIcon3D ["\a3\ui_f\data\IGUI\Cfg\Radar\radar_ca.paa", [1,1,1,1], _endW, 1, 1, 45, "Target", 1, 0.05, "TahomaB"];
};

https://imgur.com/a/bOuXWo8 Video example of the issue.

Frate