Lerp float — linearly interpolate between A and B by Alpha

UKismetMathLibrary::Lerp. Alpha 0=A, Alpha 1=B.

Lerp (float) — linear interpolate between two floats by Alpha

Alpha=0 returns A, Alpha=1 returns B. Does NOT clamp Alpha.

Lerp

Linear interpolation — returns A when Alpha=0, B when Alpha=1, and a smooth blend in between. Pair with Timeline for animation.

RLerp — linearly interpolate between two rotators

bShortestPath=true for correct interpolation around 360.

VLerp — linearly interpolate between two vectors

LinearColorLerp — blend between two colors by Alpha

Multiplayer: Server RPC for damage, Multicast RPC for effects

Pattern for shooting in multiplayer: ON CLIENT: InputAction Shoot → ServerRPC_Shoot (Custom Event, Run On Server, Reliable). ServerRPC_Shoot (runs on SERVER): LineTraceByChannel → Branch(hit) → ApplyDamage → MulticastRPC_PlayEffect(ImpactPoint). MulticastRPC_PlayEffect (Custom Event, Multicast, Unreliable): SpawnNiagaraSystemAtLocation(NS_BulletImpact, ImpactPoint). Key rules: - Server RPC: Custom Event → Replicates='Run On Server', Reliable=true. - Multicast: Custom Event → Replicates='Multicast', Reliable=false (VFX can be dropped). - Client RPC: Custom Event → Replicates='Run On Owning Client'. - Never directly modify replicated vars on clients — always go through Server RPC.

RInterpTo — smooth rotator interpolation toward target over time

Pickup and collectible system with overlap trigger

Pattern: Pickup actor with SphereCollision(overlap), StaticMesh visual. OnComponentBeginOverlap → CastTo PlayerCharacter → Success: call AddScore/AddItem interface on player → PlaySoundAtLocation → SpawnEmitterAtLocation → DestroyActor(self). Set collision to OverlapOnlyPawn for performance.

SetScalarParameterValue — set a float parameter on a dynamic material

ParameterName must match the parameter name in the Material exactly (case-sensitive).