Transition Catalog

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Each shipped transition, what it does, and what parameters drive it. See Concepts → Transitions for the pose-only contract, the four-phase lifecycle, and the five-tier resolution chain; User Guide → Transitions & Blending for authoring guidance.

Every transition inherits from UComposableCameraTransitionBase, which provides:

  • TransitionDuration — total duration in seconds. Most transitions treat this as an exact duration; InertializedTransition can treat it as a minimum.
  • TransitionEnabled / OnBeginPlay / OnEvaluate / OnFinished — the four-phase lifecycle. Subclasses typically override OnBeginPlay (to cache source-driven state) and OnEvaluate (to produce the blended pose).

The OnEvaluate contract is the same across every subclass: receive live source and target poses plus a normalized Percentage in [0, 1], return the blended pose.

LinearTransition

Straight linear interpolation of position and rotation. Lerp(source, target, Percentage).

  • Parameters: none beyond the base duration.
  • Velocity-aware: no.
  • Typical use: cheapest possible blend. Use as a baseline, or for UI-driven cuts where the source camera isn't moving.

CubicTransition

Cubic easing — smooth start and smooth end, accelerating through the middle. No tunable exponent; a fixed cubic polynomial.

  • Parameters: none beyond the base duration.
  • Velocity-aware: no.
  • Typical use: a visual step up from LinearTransition for moderate-duration blends where physical plausibility isn't required.

EaseTransition

EaseInOut with a tunable exponent.

Field Type Default Purpose
Exp float 1.0 Exponent. 1.0 behaves like a linear blend; higher values produce sharper in/out regions with a flatter middle.
  • Velocity-aware: no.
  • Typical use: when you want a specific easing feel that neither Cubic nor Smooth quite hits. Start around Exp = 2.0 and tune.

SmoothTransition

Hermite smoothstep or smootherstep — a classic S-curve blend with zero derivative at both ends.

Field Type Default Purpose
bSmootherStep bool false false → Hermite smoothstep t²(3−2t). true → smootherstep t³(t(6t−15)+10), a 5th-order polynomial with zero first and second derivative at both ends.
  • Velocity-aware: no.
  • Typical use: UI-driven blends, cinematic establishing shots, anywhere you want a clean S-curve without the velocity recovery of inertialization.

CylindricalTransition

Arcs the camera around a pivot derived from the intersection of the source and target look-at rays, instead of cutting a straight path between the two positions. The result reads like an orbital sweep rather than a teleport.

Field Type Default Purpose
MinimumDistanceFromOrigin float 10.0 Minimum distance from the derived pivot along the look direction, so the arc never passes through the pivot itself.
bLockToPivot bool true If true, the camera's rotation is locked toward the pivot throughout the arc.
  • Velocity-aware: no (but inherits the pivot from a ray intersection of the endpoints' look directions).
  • Typical use: orbital feels, "camera swoops around hero" moments, boss-reveal swings. Avoid for short gameplay blends — the arc reads as motion for its own sake.

InertializedTransition

Physics-plausible 5th-order polynomial blend. The polynomial is constructed so that, at the start of the transition, position and rotation match the source with the correct velocity (recovered from InitParams via (CurrentSourcePose − PreviousSourcePose) / DeltaTime); and at the end, position and rotation reach the target with zero velocity and zero acceleration. This produces a blend that visually respects the source camera's momentum instead of snapping to zero velocity at t=0.

Field Type Default Purpose
bAutoTransitionTime bool false If true, the transition auto-computes its own duration from MaxAcceleration instead of using TransitionDuration.
MaxAcceleration float 100.0 Acceleration cap (cm/s²) used when bAutoTransitionTime is on. Lower values produce longer, softer blends.
AdditiveCurve UCurveFloat* nullptr Optional normalized curve (x∈[0,1], y∈[0,1], f(0)=1, f(1)=0) added to the polynomial output. Lets you reshape the blend without abandoning the inertialized math.
AdditiveCurveWeight float 0.5 Overall contribution of the additive curve.
AdditiveCurveShape float 10.0 Per-phase falloff for the additive curve (how quickly it blends in near the midpoint and out near the ends).
  • Velocity-aware: yes — the default for most gameplay blends.
  • Typical use: gameplay cuts, camera-to-camera blends while the player is moving, any blend where snapping to zero velocity at the start would be visible as a kink.

See Concepts → Transitions → InitParams for why velocity matters and how FComposableCameraTransitionInitParams delivers it.

SplineTransition

The camera follows a computed spline from source to target. The spline shape is authored directly as tangents, control points, or an arc descriptor — there's no external rail actor involved (unlike PathGuidedTransition).

Field Type Default Purpose
SplineType enum Hermite Hermite / Bezier / CatmullRom / Arc. Controls which geometry fields apply.
EvaluationCurveType enum Smoother Linear / Cubic / Smooth / Smoother. How the camera's t parameter is evolved along the spline.
StartTangent FVector (0, 100, 0) (Hermite only) tangent at source, in a local frame aligned with source→target.
EndTangent FVector (0, 100, 0) (Hermite only) tangent at target.
StartControlPoint FVector (0, 100, 0) (Bezier only) cubic control point attached to source.
EndControlPoint FVector (0, 100, 0) (Bezier only) cubic control point attached to target.
ControlPoints TArray<FVector> — (CatmullRom only) intermediate knots.
ArcAngle float 180 (Arc only) span in degrees — 180 is a half circle, 90 a quarter circle, 270 a quarter circle going the long way.
ArcRoll float 0 (Arc only) roll along the source→target axis, in degrees.
  • Velocity-aware: no (the spline is pre-computed at OnBeginPlay).
  • Typical use: cinematic blends where the exact path matters and is worth authoring by hand. For rail-driven paths, prefer PathGuidedTransition.

PathGuidedTransition

Three-phase cinematic: enter from source onto a rail, follow the rail, exit to the target. An intermediate camera is spawned on the rail as a carrier. Uses two internal InertializedTransitions (for enter and exit) around a rail-follow middle phase.

Field Type Default Purpose
DrivingTransition UComposableCameraTransitionBase* (instanced) — Transition used to drive the base camera's motion underneath the path phase. Typically an InertializedTransition.
Type enum Inertialized Inertialized (two inertialized bridges) or Auto (auto-generated splines). Auto does not update the target pose each frame — don't use it if the target camera is moving.
RailActor TSoftObjectPtr<ACameraRig_Rail> — The CameraRig_Rail whose spline the camera follows in the middle phase.
GuideRange FVector2D (0.25, 0.75) Normalized percentages marking the start and end of the guide phase. The blend spends [0, start] entering the rail, [start, end] following it, [end, 1] exiting.
SplineMoveCurve UCurveFloat* — Optional normalized curve ([0, 1] → [0, 1]) controlling how fast the intermediate camera progresses along the rail.
  • Velocity-aware: yes on enter and exit (via the inertialized bridges).
  • Cost: higher than other transitions — spawns an intermediate camera actor and duplicates the rail's spline component. Use for set pieces, not gameplay.
  • Typical use: cinematic swoops, lift-off shots, "camera leaves the player and flies to the vista" moments.

DynamicDeocclusionTransition

A wrapper around another transition. Each frame it casts one or more "feeler" rays from the wrapped transition's output pose toward the target; if any feeler is blocked, it nudges the output pose along the unblocked feeler direction, preventing the blend from passing through occluders. Clears back to the base pose when occlusion resolves.

Field Type Default Purpose
DrivingTransition UComposableCameraTransitionBase* (instanced) — The wrapped transition that actually computes the base blended pose. The deocclusion pass runs on top of that.
Feelers TArray<FComposableCameraRayFeeler> — Rays to probe for occlusion. Each feeler has Yaw, Pitch, Length, Radius, Offset, and a StrengthCurve.
TraceChannel TEnumAsByte<ETraceTypeQuery> — Collision channel used for all feeler traces.
ActorTypesToIgnore TArray<TSoftClassPtr<AActor>> — Actor classes whose instances are ignored by the feelers.
DeocclusionSpeed float 1.0 How fast the camera pushes off an occlusion.
ResumeWaitingTime float 0.2 Seconds to wait with no occlusion detected before returning to the base pose.
DeadPercentage float 0.8 Past this normalized blend percentage, deocclusion is ignored — the transition commits to the target.
ResumeSpeed float 0.8 How fast the camera returns to the base pose once deocclusion clears.
  • Velocity-aware: depends on the DrivingTransition. Usually wrap an InertializedTransition.
  • Typical use: long blends in geometry-dense environments — cinematic pans through corridors, third-person → aim transitions around corners, anywhere the blend path might pass through a wall.

See also: User Guide → Transitions & Blending for authoring and tuning; Extending → Custom Transitions for writing your own.

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