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BT TurnInPlace - constant-rate turning, and the stock focus pattern

TL;DR: For continuous "keep facing while doing other things", use the stock UBTService_DefaultFocus. For a discrete turn at a constant rate, use LCM_BTTask_TurnInPlace, which ships with the plugin.

See Look At for the full comparison between the stock rotation task and the LCM Nav3D ones. The short version: the stock task's success test projects onto the XY plane and its applied rotation drops pitch, so on a flying agent with a target overhead it can report success while still pointing level.

Pattern: continuous facing during other tasks

If you want the agent to keep facing a target while executing other tasks in a parent sequence, this is the stock pattern and LCM Nav3D does not replace it:

  1. Add UBTService_DefaultFocus to the parent Selector or Sequence.
  2. Set the focus blackboard key (Vector or Object).
  3. The AIController's focus stays set for the entire subtree, so the pawn faces the target through SetFocus while other tasks execute.

This is the canonical UE pattern for "shoot while strafing" combat AI.

⚠ A focus service and a rotation task will fight each other. The controller re-asserts focus rotation every tick, overwriting anything a task writes, and this has been observed to stall an agent outright. Use a focus service for continuous facing or a rotation task for a discrete turn, not both on the same subtree.

Pattern: a discrete constant-rate turn

LCM_BTTask_TurnInPlace turns toward the target at MaxRotationRateDegPerSec and succeeds once it is pointing within AcceptableErrorDegrees.

Sequence
  LCM TurnInPlace   (TargetKey = ThreatActor, MaxRotationRateDegPerSec = 180)
  <your next task>

Constant rate is the difference from LCM_BTTask_LookAt, which eases toward the target instead. Use the constant rate when the turn speed is a character trait you want to be visible and consistent, for instance a heavy gun platform that traverses slowly. Both tasks share the same underlying implementation and the same properties otherwise.

bHoldStation defaults on, so the agent holds its position through the turn rather than drifting.

Property list

See the API Reference entry for LcmBTTask_TurnInPlace.

On 6-DOF flight bodies

Where LcmFlightMovementComponent is driving the pawn with the flight dynamics locomotion model, that component owns orientation and derives it from its own dynamics. The task reports the facing as unsupported rather than pretending, and still succeeds so surrounding sequences continue to work. Agents on the default kinematic locomotion model rotate normally.

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