Position

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Introduction

Positions in Arma are always represented as arrays. There are two types of positions:

  • 2D positions: [X, Y]
  • 3D positions: [X, Y, Z]

On the map, the X-axis runs from west to east and the Y-axis runs from south to north. The origin [0, 0] is (usually) located in the bottom left corner.
While the Z-coordinate is always the height, the point relative to which that height is measured depends on the specific position format (see below).

Since Arma 3 v1.93.145664: X, Y and Z are limited to values between -50km and +500km.

Formats

A comparison of the most common formats

There are a number of formats available in Real Virtuality:

ASL: Presumably "Above Sea Level"
ATL: Presumably "Above Terrain Level"
ASLW: Presumably "Above Sea Level including Waves"
AGL: Presumably "Above Generic/Ground Level"
AGLS: Presumably "Above Generic/Ground Level including Surfaces"
World: Raw world coordinate system
Relative: Position relative to an object within its model space
Config: Position used in configs
Object: When object is used for position, PositionWorld of the object is used

PositionASL

Z is measured from the sea level which is constant across the map.

See also: getPosASL, setPosASL, getPosASLVisual, visiblePositionASL, ASLToATL, ATLToASL, AGLToASL, ASLToAGL, eyePos, aimPos, getTerrainHeightASL, lineIntersects, lineIntersectsWith, lineIntersectsObjs, lineIntersectsSurfaces, terrainIntersectASL, playSound3D, setDefaultCamera

PositionASLW

Z is measured from the surface of the sea that could be higher or lower than sea level due to waves.

See also: getPosASLW, setPosASLW

PositionATL

Z is measured from the terrain level which varies across the map.

See also: getPosATL, setPosATL, getPosATLVisual, ASLToATL, ATLToASL

PositionAGL

Z is the same as in PositionASLW when over sea and is the same as in PositionATL when over land. Most commands either take or return PositionAGL.

See also: modelToWorld, worldToModel, modelToWorldVisual, worldToModelVisual, positionCameraToWorld, intersect, terrainIntersect, isOnRoad, drawIcon3D, drawLine3D, distance, moveTo, doMove, move, setDestination, buildingPos, screenToWorld, worldToScreen, AGLToASL, ASLToAGL, unitAimPosition, unitAimPositionVisual

PositionAGLS

Over land, Z is measured as height over terrain level minus the height of surface over terrain level underneath. If such surface exists and is counted in, the resulting Z becomes 0.

Obtaining Z for a unit standing on a rock

Over sea it gets even more complicated as instead of PositionATL, PositionASLW is used minus the offset for the surface height, presumably over waves too, as Z seems static. As there is currently no way to obtain Hsurface, it becomes impossible to convert given PositionAGLS into other formats, unlike with other position formats.

See also: position, visiblePosition, getPos, getPosVisual

setPosAGLS

The function below will place passed object onto walkable surface, if there is one, otherwise on the ground. If only X and Y of the position are supplied, the object will be placed on surface, if Z is supplied, it will be treated as offset from the surface level.

KK_fnc_setPosAGLS = { params ["_obj", "_pos", "_offset"]; _offset = _pos select 2; if (isNil "_offset") then {_offset = 0}; _pos set [2, worldSize]; _obj setPosASL _pos; _pos set [2, vectorMagnitude (_pos vectorDiff getPosVisual _obj) + _offset]; _obj setPosASL _pos; }; // This will place the player exactly on top deck of Cargo HQ on Stratis: [player, [2437.18,5693.47,0]] call KK_fnc_setPosAGLS;
// This will place the player 2m above top deck of Cargo HQ on Stratis: [player, [2437.18,5693.47,2]] call KK_fnc_setPosAGLS;
// This will place the player 2m below top deck of Cargo HQ on Stratis: [player, [2437.18,5693.47,-2]] call KK_fnc_setPosAGLS;

Alternatively, setVehiclePosition can be used. It will put the object onto the nearest surface. // This will place the player inside Cargo HQ on Stratis: player setVehiclePosition [[2437.18,5693.47,0], [], 0, "CAN_COLLIDE"];
// This will place the player on top deck of Cargo HQ on Stratis: player setVehiclePosition [[2437.18,5693.47,100], [], 0, "CAN_COLLIDE"];

PositionWorld

Similar to PositionASL, however Z is measured from the sea level to the the model centre [0, 0, 0] of the object, rather than transformed boundingCenter or land contact vertices. _identical = getPosWorld _obj isEqualTo AGLtoASL (_obj modelToWorld [0,0,0]); // should be true

See also: getPosWorld, setPosWorld, mapCenterOnCamera

PositionRelative

Relative position is normally an [X, Y, Z] offset from the model centre.

See also: positionCameraToWorld, selectionPosition, attachTo, modelToWorld, worldToModel, modelToWorldVisual, worldToModelVisual, camPrepareRelPos, camSetRelPos

PositionConfig

The format used in configs, such as mission.sqm, is [X, Z, Y], where Z and Y are swapped around. One other command that uses this format is positionCameraToWorld. Z in configs is measured from the sea level.