Class ObstacleAvoidanceBehavior

Namespace: mobisim.Actors.AI.Steer

Steering behaviour that deflects the actor's heading away from detected obstacles using a forward sphere-cast fan.

public class ObstacleAvoidanceBehavior : SteeringBehaviour, IHandler

Inheritance

object→Object→Component→Behaviour→MonoBehaviour→SteeringBehaviour→ObstacleAvoidanceBehavior

Implements

IHandler

Inherited Members

• SteeringBehaviour.m_Solver
• SteeringBehaviour.Handle(object)
• SteeringBehaviour.SetNext(IHandler)
• SteeringBehaviour.Start()
• SteeringBehaviour.GetSteering(Vector3)

Remarks

A sphere-cast fan (multiple rays spread across ray_Angle degrees) is used instead of a single forward ray because a single ray misses obstacles that are slightly off-axis — common in narrow street scenarios. The sphere radius adds lateral margin so that the actor does not clip obstacles that are only just inside the physical collider boundary.

ObstacleToIgnore allows the actor's own collider (and collaborating actors such as the player) to be excluded from avoidance, preventing self-avoidance loops where the actor would try to steer away from itself.

Fields

ObstacleToIgnore

The list of obstacles that should be ignored during obstacle avoidance. These are objects that the behavior will not consider as obstacles.

[SerializeField]
protected GameObject[] ObstacleToIgnore

Field Value

GameObject[]

ray_Angle

The angle spread for the rays to be cast. This defines how wide the spread of the rays will be, measured in degrees.

[Range(0, 360)]
public int ray_Angle

Field Value

int

ray_numer

The number of rays to cast in different directions for obstacle detection. This allows for multi-ray casting for better detection coverage.

[Min(0)]
public int ray_numer

Field Value

int

Methods

GetSteering(Vector3)

Calculates the steering force to avoid obstacles while moving towards the target.

public override Vector3 GetSteering(Vector3 TargetVector)

Parameters

Name	Type	Description
TargetVector	Vector3	The accumulated steering vector passed in from earlier chain nodes.

Returns

Vector3 — The steering force to avoid obstacles while moving towards the target.

Remarks

The early-exit guard if (Velocity == Vector3.zero) return TargetVector is a safety check, not a performance optimisation. Vector3) called with zero as its forward argument throws an ArgumentException in Unity because a zero-length vector has no defined orientation. Returning the unchanged TargetVector when the actor is stationary is correct behaviour as well: there is nothing to deflect away from a direction that does not yet exist.

IsIgnored(RaycastHit)

Checks if the given raycast hit should be ignored (i.e., it hits an object to be avoided).

protected bool IsIgnored(RaycastHit hit)

Parameters

Name	Type	Description
hit	RaycastHit	The raycast hit result.

Returns

bool — True if the hit should be ignored, false otherwise.

IsIgnored(Collider)

Checks if the given collider should be ignored (e.g., if it belongs to an obstacle to avoid).

protected bool IsIgnored(Collider col)

Parameters

Name	Type	Description
col	Collider	The collider to check.

Returns

bool — True if the collider should be ignored, false otherwise.

Start()

Initializes the SteeringSolver component at the start.

protected override void Start()