Melee Trace

Can Play Ahead on every effect says whether the attacking player's own machine plays it the moment the swing connects, before the server has answered the hit. It matters only for a player who predicts their own swings. It answers true unless the effect waits on that answer, which Suppress on Result Tags, Require Any Result Tags and Require Damage Applied all do. An effect only the server can carry out, such as SEC Apply Gameplay Effect, never plays ahead.

An effect that waits runs on the server, which sends it to the attacking player's machine a moment after contact. An impact that plays ahead and a parry spark that waits can sit side by side, so a parried blow shows the impact at contact and the spark once the answer arrives. A Blueprint effect overrides Can Play Ahead to return false for work that has to run on the server alone; decide it from the effect's own settings, since the attacker's machine asks before any answer exists.

A collider can sit in front of a character without taking the swings that cross it: a parry box, a volume that wakes something up, a hitbox your own code counts.

A swing crossing it fires On Melee Sensed carrying the struck component, spends nothing, and reaches the body behind it in the same frame. Each sensor reports once per window however many frames the swing spends inside it.

On Block the sweep stops at the sensor and never reaches the body. The Output Log warns and names the component when that happens.

Leave Sense Component Tags empty and every contact counts as a body.

Every hit carries the bearing from attacker to target, which is what a directional guard or a reaction reads. Is Hit Direction Within Arc answers whether it arrived inside a front arc of a given half angle, and Get Hit Direction Quadrant buckets it into Front, Back, Left or Right.

Tick Use Authored Hit Direction on the damage config to send a fixed direction instead, so an uppercut launches upward whatever the geometry said. Authored Hit Direction Local is that direction in the attacker's local space, and (0,0,1) throws the target up. The physics impulse follows the same value.

Sockets take the component's Trace Filter by default. Tick the box beside Trace Filter Override on one entry and fill it in to give that contact point its own rule, for a pickaxe head that also breaks rocks while the haft keeps the ordinary filter.

Make a Blueprint child of the SEC Melee Trace component, put that child on the character in place of the base, and override the event for the phase you want to change. Every other phase carries on as it is.

Three nodes support those overrides. Can Hit Actor answers whether the swing may still land on a target, Record Hit spends the swing on one, and Get Targets Hit This Window counts what it has already struck, which is what damage falloff across a cleave reads.

Build Damage Info hands the target the damage config the attack was authored on. Make a child of SEC Damage Config to carry whatever else an attack needs, poise damage or a stagger tier, and cast it in the target's Handle Incoming Damage.

A pawn with no weapon registers its own sockets from Blueprint, usually on Begin Play. Three nodes on the trace component cover it:

Give each an ID and name it on the montage window exactly as a weapon's socket would be named. Unregister Trace Socket and Unregister All Sockets take them away again.

Damage Application on the component picks what a landed hit does.

On None, bind On Melee Hit and do the whole thing yourself. The event carries the hit result, the socket that struck, the damage config the window opened with, and how the trace sorted the contact.

SEC Damage Statics opens the melee path to any other source, so an arrow and a sword resolve the same way.

The first two apply damage on the server and report an empty result anywhere else.

Three nodes on the trace component drive a window by hand, for an attack whose timing comes from somewhere other than a montage.

Get Registered Socket IDs lists what is there to name, and Is Tracing answers whether a window is open.

The authority sweeps for hits and every other machine stays out of it, which is what keeps one swing from landing twice. On Melee Hit, On Melee Hit Response and On Melee Sensed therefore fire on the server alone.

A cue effect fired there multicasts through the ability system and reaches every client, so impact feedback still plays for everyone.

Two things bite a project that moves detection to the owning client. A team id held on a controller reads as no team on a client, since a controller replicates only to its own player, so put the id on the pawn. And a cue fired off the authority outside a prediction window plays nothing, so a client-detected hit needs its cues driven locally.

See Multiplayer.