Class LegacyAIPath Extends AIPath

bool closestOnPathCheck = true

Do a closest point on path check when receiving path callback.

Usually the AI has moved a bit between requesting the path, and getting it back, and there is usually a small gap between the AI and the closest node. If this option is enabled, it will simulate, when the path callback is received, movement between the closest node and the current AI position. This helps to reduce the moments when the AI just get a new path back, and thinks it ought to move backwards to the start of the new path even though it really should just proceed forward.

float forwardLook = 1

Target point is Interpolated on the current segment in the path so that it has a distance of forwardLook from the AI.

See the detailed description of AIPath for an illustrative image

bool alwaysDrawGizmos

Draws detailed gizmos constantly in the scene view instead of only when the agent is selected and settings are being modified.

bool canMove = true

Enables or disables movement completely.

If you want the agent to stand still, but still react to local avoidance and use gravity: use isStopped instead.

This is also useful if you want to have full control over when the movement calculations run. Take a look at MovementUpdate

bool canSearch = true

Enables or disables recalculating the path at regular intervals.

Setting this to false does not stop any active path requests from being calculated or stop it from continuing to follow the current path.

Note that this only disables automatic path recalculations. If you call the SearchPath() method a path will still be calculated.

bool constrainInsideGraph = false

Ensure that the character is always on the traversable surface of the navmesh.

When this option is enabled a GetNearest query will be done every frame to find the closest node that the agent can walk on and if the agent is not inside that node, then the agent will be moved to it.

This is especially useful together with local avoidance in order to avoid agents pushing each other into walls.

This option also integrates with local avoidance so that if the agent is say forced into a wall by other agents the local avoidance system will be informed about that wall and can take that into account.

Enabling this has some performance impact depending on the graph type (pretty fast for grid graphs, slightly slower for navmesh/recast graphs). If you are using a navmesh/recast graph you may want to switch to the RichAI movement script which is specifically written for navmesh/recast graphs and does this kind of clamping out of the box. In many cases it can also follow the path more smoothly around sharp bends in the path.

It is not recommended that you use this option together with the funnel modifier on grid graphs because the funnel modifier will make the path go very close to the border of the graph and this script has a tendency to try to cut corners a bit. This may cause it to try to go slightly outside the traversable surface near corners and that will look bad if this option is enabled.

Below you can see an image where several agents using local avoidance were ordered to go to the same point in a corner. When not constraining the agents to the graph they are easily pushed inside obstacles.

Vector3 desiredVelocity

Velocity that this agent wants to move with.

Includes gravity and local avoidance if applicable.

Vector3 destination

Position in the world that this agent should move to.

If no destination has been set yet, then (+infinity, +infinity, +infinity) will be returned.

Note that setting this property does not immediately cause the agent to recalculate its path. So it may take some time before the agent starts to move towards this point. Most movement scripts have a repathRate field which indicates how often the agent looks for a new path. You can also call the SearchPath method to immediately start to search for a new path. Paths are calculated asynchronously so when an agent starts to search for path it may take a few frames (usually 1 or 2) until the result is available. During this time the #pathPending property will return true.

If you are setting a destination and then want to know when the agent has reached that destination then you could either use #reachedDestination (recommended) or check both #pathPending and #reachedEndOfPath. Check the documentation for the respective fields to learn about their differences.

IEnumerator Start () {
ai.destination = somePoint;
// Start to search for a path to the destination immediately
ai.SearchPath();
// Wait until the agent has reached the destination
while (!ai.reachedDestination) {
yield return null;
}
// The agent has reached the destination now
}
IEnumerator Start () {
ai.destination = somePoint;
// Start to search for a path to the destination immediately
// Note that the result may not become available until after a few frames
// ai.pathPending will be true while the path is being calculated
ai.SearchPath();
// Wait until we know for sure that the agent has calculated a path to the destination we set above
while (ai.pathPending || !ai.reachedEndOfPath) {
yield return null;
}
// The agent has reached the destination now
}


bool enableRotation = true

If true, the AI will rotate to face the movement direction.

float endReachedDistance = 0.2F

Distance to the end point to consider the end of path to be reached.

When the end is within this distance then OnTargetReached will be called and reachedEndOfPath will return true.

void FinalizeMovement (

Vector3	nextPosition	New position of the agent.
Quaternion	nextRotation	New rotation of the agent. If enableRotation is false then this parameter will be ignored.

)

Moves the agent to a position.

This is used if you want to override how the agent moves. For example if you are using root motion with Mecanim.

This will use a CharacterController, Rigidbody, Rigidbody2D or the Transform component depending on what options are available.

The agent will be clamped to the navmesh after the movement (if such information is available, generally this is only done by the RichAI component).

void FindComponents ()

Looks for any attached components like RVOController and CharacterController etc.

This is done during OnEnable. If you are adding/removing components during runtime you may want to call this function to make sure that this script finds them. It is unfortunately prohibitive from a performance standpoint to look for components every frame.

Vector3 GetFeetPosition ()

Position of the base of the character.

This is used for pathfinding as the character's pivot point is sometimes placed at the center of the character instead of near the feet. In a building with multiple floors the center of a character may in some scenarios be closer to the navmesh on the floor above than to the floor below which could cause an incorrect path to be calculated. To solve this the start point of the requested paths is always at the base of the character.

Vector3 gravity = new Vector3(float.NaN, float.NaN, float.NaN)

Gravity to use.

If set to (NaN,NaN,NaN) then Physics.Gravity (configured in the Unity project settings) will be used. If set to (0,0,0) then no gravity will be used and no raycast to check for ground penetration will be performed.

LayerMask groundMask = -1

Layer mask to use for ground placement.

Make sure this does not include the layer of any colliders attached to this gameobject.

bool hasPath

True if this agent currently has a path that it follows.

float height = 2

Radius of the agent in world units.

This is visualized in the scene view as a yellow cylinder around the character.

bool isStopped

Gets or sets if the agent should stop moving.

If this is set to true the agent will immediately start to slow down as quickly as it can to come to a full stop. The agent will still react to local avoidance and gravity (if applicable), but it will not try to move in any particular direction.

The current path of the agent will not be cleared, so when this is set to false again the agent will continue moving along the previous path.

This is a purely user-controlled parameter, so for example it is not set automatically when the agent stops moving because it has reached the target. Use #reachedEndOfPath for that.

If this property is set to true while the agent is traversing an off-mesh link (RichAI script only), then the agent will continue traversing the link and stop once it has completed it.

The #steeringTarget property will continue to indicate the point which the agent would move towards if it would not be stopped.

float maxAcceleration = -2.5f

How quickly the agent accelerates.

Positive values represent an acceleration in world units per second squared. Negative values are interpreted as an inverse time of how long it should take for the agent to reach its max speed. For example if it should take roughly 0.4 seconds for the agent to reach its max speed then this field should be set to -1/0.4 = -2.5. For a negative value the final acceleration will be: -acceleration*maxSpeed. This behaviour exists mostly for compatibility reasons.

In the Unity inspector there are two modes: Default and Custom. In the Default mode this field is set to -2.5 which means that it takes about 0.4 seconds for the agent to reach its top speed. In the Custom mode you can set the acceleration to any positive value.

float maxSpeed = 1

Max speed in world units per second.

void Move (

Vector3

deltaPosition

Direction and distance to move the agent in world space.

)

Move the agent.

This is intended for external movement forces such as those applied by wind, conveyor belts, knockbacks etc.

Some movement scripts may ignore this completely (notably the AILerp script) if it does not have any concept of being moved externally.

The agent will not be moved immediately when calling this method. Instead this offset will be stored and then applied the next time the agent runs its movement calculations (which is usually later this frame or the next frame). If you want to move the agent immediately then call: ai.Move(someVector);
ai.FinalizeMovement(ai.position, ai.rotation);


IMovementPlane movementPlane = GraphTransform.identityTransform

Plane which this agent is moving in.

This is used to convert between world space and a movement plane to make it possible to use this script in both 2D games and 3D games.

void MovementUpdate (

float	deltaTime	time to simulate movement for. Usually set to Time.deltaTime.
out Vector3	nextPosition	the position that the agent wants to move to during this frame.
out Quaternion	nextRotation	the rotation that the agent wants to rotate to during this frame.

)

Calculate how the character wants to move during this frame.

Note that this does not actually move the character. You need to call FinalizeMovement for that. This is called automatically unless canMove is false.

To handle movement yourself you can disable canMove and call this method manually. This code will replicate the normal behavior of the component: void Update () {
// Disable the AIs own movement code
ai.canMove = false;
Vector3 nextPosition;
Quaternion nextRotation;
// Calculate how the AI wants to move
ai.MovementUpdate(Time.deltaTime, out nextPosition, out nextRotation);
// Modify nextPosition and nextRotation in any way you wish
// Actually move the AI
ai.FinalizeMovement(nextPosition, nextRotation);
}


System.Action onSearchPath

Called when the agent recalculates its path.

This is called both for automatic path recalculations (see canSearch) and manual ones (see SearchPath).

void OnTargetReached ()

The end of the path has been reached.

If you want custom logic for when the AI has reached it's destination add it here. You can also create a new script which inherits from this one and override the function in that script.

This method will be called again if a new path is calculated as the destination may have changed. So when the agent is close to the destination this method will typically be called every repathRate seconds.

OrientationMode orientation = OrientationMode.ZAxisForward

Determines which direction the agent moves in.

For 3D games you most likely want the ZAxisIsForward option as that is the convention for 3D games. For 2D games you most likely want the YAxisIsForward option as that is the convention for 2D games.

Using the YAxisForward option will also allow the agent to assume that the movement will happen in the 2D (XY) plane instead of the XZ plane if it does not know. This is important only for the point graph which does not have a well defined up direction. The other built-in graphs (e.g the grid graph) will all tell the agent which movement plane it is supposed to use.

bool pathPending

True if a path is currently being calculated.

float pickNextWaypointDist = 2

How far the AI looks ahead along the path to determine the point it moves to.

In world units. If you enable the alwaysDrawGizmos toggle this value will be visualized in the scene view as a blue circle around the agent.

Here are a few example videos showing some typical outcomes with good values as well as how it looks when this value is too low and too high.

Vector3 position

Position of the agent.

In world space. If updatePosition is true then this value is idential to transform.position.

float radius = 0.5f

Height of the agent in world units.

This is visualized in the scene view as a yellow cylinder around the character.

This value is currently only used if an RVOController is attached to the same GameObject, otherwise it is only used for drawing nice gizmos in the scene view. However since the height value is used for some things, the radius field is always visible for consistency and easier visualization of the character. That said, it may be used for something in a future release.

bool reachedDestination

True if the ai has reached the destination.

This is a best effort calculation to see if the destination has been reached. For the AIPath/RichAI scripts, this is when the character is within endReachedDistance world units from the destination. For the AILerp script it is when the character is at the destination (±a very small margin).

This value will be updated immediately when the destination is changed (in contrast to reachedEndOfPath), however since path requests are asynchronous it will use an approximation until it sees the real path result. What this property does is to check the distance to the end of the current path, and add to that the distance from the end of the path to the destination (i.e. is assumes it is possible to move in a straight line between the end of the current path to the destination) and then checks if that total distance is less than endReachedDistance. This property is therefore only a best effort, but it will work well for almost all use cases.

Furthermore it will not report that the destination is reached if the destination is above the head of the character or more than half the height of the character below its feet (so if you have a multilevel building, it is important that you configure the height of the character correctly).

The cases which could be problematic are if an agent is standing next to a very thin wall and the destination suddenly changes to the other side of that thin wall. During the time that it takes for the path to be calculated the agent may see itself as alredy having reached the destination because the destination only moved a very small distance (the wall was thin), even though it may actually be quite a long way around the wall to the other side.

In contrast to reachedEndOfPath, this property is immediately updated when the destination is changed.

IEnumerator Start () {
ai.destination = somePoint;
// Start to search for a path to the destination immediately
ai.SearchPath();
// Wait until the agent has reached the destination
while (!ai.reachedDestination) {
yield return null;
}
// The agent has reached the destination now
}


bool reachedEndOfPath

True if the agent has reached the end of the current path.

Note that setting the destination does not immediately update the path, nor is there any guarantee that the AI will actually be able to reach the destination that you set. The AI will try to get as close as possible. Often you want to use reachedDestination instead which is easier to work with.

It is very hard to provide a method for detecting if the AI has reached the destination that works across all different games because the destination may not even lie on the navmesh and how that is handled differs from game to game (see also the code snippet in the docs for destination).

float remainingDistance

Remaining distance along the current path to the end of the path.

For the RichAI movement script this may not always be precisely known, especially when far away from the destination. In those cases an approximate distance will be returned.

If the agent does not currently have a path, then positive infinity will be returned.

float repathRate = 0.5f

Determines how often the agent will search for new paths (in seconds).

The agent will plan a new path to the target every N seconds.

If you have fast moving targets or AIs, you might want to set it to a lower value.

Quaternion rotation

Rotation of the agent.

If updateRotation is true then this value is identical to transform.rotation.

float rotationSpeed = 360

Rotation speed in degrees per second.

Rotation is calculated using Quaternion.RotateTowards. This variable represents the rotation speed in degrees per second. The higher it is, the faster the character will be able to rotate.

void SearchPath ()

Recalculate the current path.

You can for example use this if you want very quick reaction times when you have changed the destination so that the agent does not have to wait until the next automatic path recalculation (see canSearch).

If there is an ongoing path calculation, it will be canceled, so make sure you leave time for the paths to get calculated before calling this function again. A canceled path will show up in the log with the message "Canceled by script" (see #Seeker.CancelCurrentPathRequest()).

If no destination has been set yet then nothing will be done.

void SetPath (

Path

path

)

Make the AI follow the specified path.

In case the path has not been calculated, the script will call seeker.StartPath to calculate it. This means the AI may not actually start to follow the path until in a few frames when the path has been calculated. The #pathPending field will as usual return true while the path is being calculated.

In case the path has already been calculated it will immediately replace the current path the AI is following. This is useful if you want to replace how the AI calculates its paths. Note that if you calculate the path using seeker.StartPath then this script will already pick it up because it is listening for all paths that the Seeker finishes calculating. In that case you do not need to call this function.

If you pass null as a parameter then the current path will be cleared and the agent will stop moving. Note than unless you have also disabled canSearch then the agent will soon recalculate its path and start moving again.

You can disable the automatic path recalculation by setting the canSearch field to false.

// Disable the automatic path recalculation
ai.canSearch = false;
var pointToAvoid = enemy.position;
// Make the AI flee from the enemy.
// The path will be about 20 world units long (the default cost of moving 1 world unit is 1000).
var path = FleePath.Construct(ai.position, pointToAvoid, 1000 * 20);
ai.SetPath(path);

// If you want to make use of properties like ai.reachedDestination or ai.remainingDistance or similar
// you should also set the destination property to something reasonable.
// Since the agent's own path recalculation is disabled, setting this will not affect how the paths are calculated.
// ai.destination = ...


Color ShapeGizmoColor = new Color(240/255f, 213/255f, 30/255f)

Quaternion SimulateRotationTowards (

Vector3	direction	Direction in world space to rotate towards.
float	maxDegrees	Maximum number of degrees to rotate this frame.

)

Simulates rotating the agent towards the specified direction and returns the new rotation.

Note that this only calculates a new rotation, it does not change the actual rotation of the agent. Useful when you are handling movement externally using FinalizeMovement but you want to use the built-in rotation code.

float slowdownDistance = 0.6F

Distance from the end of the path where the AI will start to slow down.

bool slowWhenNotFacingTarget = true

Slow down when not facing the target direction.

Incurs at a small performance overhead.

Vector3 steeringTarget

Point on the path which the agent is currently moving towards.

This is usually a point a small distance ahead of the agent or the end of the path.

If the agent does not have a path at the moment, then the agent's current position will be returned.

void Teleport (

Vector3	newPosition
bool	clearPath=true

)

Instantly move the agent to a new position.

This will trigger a path recalculation (if clearPath is true, which is the default) so if you want to teleport the agent and change its destination it is recommended that you set the destination before calling this method.

The current path will be cleared by default.

bool updatePosition = true

Determines if the character's position should be coupled to the Transform's position.

If false then all movement calculations will happen as usual, but the object that this component is attached to will not move instead only the position property will change.

This is useful if you want to control the movement of the character using some other means such as for example root motion but still want the AI to move freely.

bool updateRotation = true

Determines if the character's rotation should be coupled to the Transform's rotation.

If false then all movement calculations will happen as usual, but the object that this component is attached to will not rotate instead only the rotation property will change.

Vector3 velocity

Actual velocity that the agent is moving with.

In world units per second.

CloseToDestinationMode whenCloseToDestination = CloseToDestinationMode.Stop

What to do when within endReachedDistance units from the destination.

The character can either stop immediately when it comes within that distance, which is useful for e.g archers or other ranged units that want to fire on a target. Or the character can continue to try to reach the exact destination point and come to a full stop there. This is useful if you want the character to reach the exact point that you specified.

void ApplyGravity (

float

deltaTime

)

Accelerates the agent downwards.

void Awake ()

Vector2 CalculateDeltaToMoveThisFrame (

Vector2	position
float	distanceToEndOfPath
float	deltaTime

)

Calculates how far to move during a single frame.

void CalculateNextRotation (

float	slowdown
out Quaternion	nextRotation

)

void CalculatePathRequestEndpoints (

out Vector3	start
out Vector3	end

)

Outputs the start point and end point of the next automatic path request.

This is a separate method to make it easy for subclasses to swap out the endpoints of path requests. For example the #LocalSpaceRichAI script which requires the endpoints to be transformed to graph space first.

Vector3 CalculateTargetPoint (

Vector3	p	Current position
Vector3	a	Line segment start
Vector3	b	Line segment end The returned point will lie somewhere on the line segment.

)

Calculates target point from the current line segment.

Vector3 CalculateVelocity (

Vector3

currentPosition

)

Calculates desired velocity.

Finds the target path segment and returns the forward direction, scaled with speed. A whole bunch of restrictions on the velocity is applied to make sure it doesn't overshoot, does not look too far ahead, and slows down when close to the target. /see speed /see endReachedDistance /see slowdownDistance /see CalculateTargetPoint /see targetPoint /see targetDirection /see currentWaypointIndex

void CancelCurrentPathRequest ()

Vector3 ClampToNavmesh (

Vector3	position	Current position of the character.
out bool	positionChanged	True if the character's position was modified by this method.

)

Constrains the character's position to lie on the navmesh.

Not all movement scripts have support for this.

void ClearPath ()

Clears the current path of the agent.

Usually invoked using #SetPath(null)

CharacterController controller

Cached CharacterController component.

int currentWaypointIndex = 0

Current index in the path which is current target.

void FixedUpdate ()

Called every physics update.

If rigidbodies are used then all movement happens here.

PathInterpolator interpolator = new PathInterpolator()

Helper which calculates points along the current path.

Vector2 lastDeltaPosition

Amount which the character wants or tried to move with during the last frame.

float lastDeltaTime

Delta time used for movement during the last frame.

Vector3 lastFoundWaypointPosition

float lastFoundWaypointTime = -9999

float lastRepath = float.NegativeInfinity

Time when the last path request was started.

float minMoveScale = 0.05F

void MovementUpdateInternal (

float	deltaTime
out Vector3	nextPosition
out Quaternion	nextRotation

)

Called during either Update or FixedUpdate depending on if rigidbodies are used for movement or not.

void OnDisable ()

void OnDrawGizmos ()

void OnDrawGizmosSelected ()

void OnEnable ()

Called when the component is enabled.

void OnPathComplete (

Path

_p

)

Called when a requested path has finished calculation.

A path is first requested by SearchPath, it is then calculated, probably in the same or the next frame. Finally it is returned to the seeker which forwards it to this function.

int OnUpgradeSerializedData (

int	version
bool	unityThread

)

Handle serialization backwards compatibility.

Path path

Current path which is followed.

int prevFrame

Last frame index when prevPosition1 was updated.

Vector3 prevPosition1

Position of the character at the end of the last frame.

Vector3 prevPosition2

Position of the character at the end of the frame before the last frame.

Vector3 RaycastPosition (

Vector3	position	Position of the character in the world.
float	lastElevation	Elevation coordinate before the agent was moved. This is along the 'up' axis of the movementPlane.

)

Checks if the character is grounded and prevents ground penetration.

Sets verticalVelocity to zero if the character is grounded.

void Reset ()

Handle serialization backwards compatibility.

Rigidbody rigid

Cached Rigidbody component.

Rigidbody2D rigid2D

Cached Rigidbody component.

void RotateTowards (

Vector3

dir

)

Rotates in the specified direction.

Rotates around the Y-axis.

RVOController rvoController

Cached RVOController component.

Seeker seeker

Cached Seeker component.

bool shouldRecalculatePath

True if the path should be automatically recalculated as soon as possible.

Vector3 simulatedPosition

Position of the agent.

If updatePosition is true then this value will be synchronized every frame with Transform.position.

Quaternion simulatedRotation

Rotation of the agent.

If updateRotation is true then this value will be synchronized every frame with Transform.rotation.

Quaternion SimulateRotationTowards (

Vector2	direction	Direction in the movement plane to rotate towards.
float	maxDegrees	Maximum number of degrees to rotate this frame.

)

Simulates rotating the agent towards the specified direction and returns the new rotation.

Note that this only calculates a new rotation, it does not change the actual rotation of the agent.

void Start ()

Starts searching for paths.

If you override this method you should in most cases call base.Start () at the start of it.

Vector3 targetDirection

Relative direction to where the AI is heading.

Filled in by CalculateVelocity

Transform tr

Cached Transform component.

void Update ()

Called every frame.

If no rigidbodies are used then all movement happens here.

void UpdateVelocity ()

bool usingGravity

Indicates if gravity is used during this frame.

Vector2 velocity2D

Current desired velocity of the agent (does not include local avoidance and physics).

Lies in the movement plane.

float verticalVelocity

Velocity due to gravity.

Perpendicular to the movement plane.

When the agent is grounded this may not accurately reflect the velocity of the agent. It may be non-zero even though the agent is not moving.

bool waitingForPathCalculation = false

Only when the previous path has been calculated should the script consider searching for a new path.

float XZSqrMagnitude (

Vector3	a
Vector3	b

)