PawnSwap
Pawn switching, possession and vehicle seats

Overview

PawnSwap is built from three components and a function library:

• Pawn Swap Manager (UPawnSwapManagerComponent) on the PlayerController: switching, roster, entering/exiting seats, interaction, spectating, input and save data.
• Pawn Swap Seat (UPawnSwapSeatComponent) on a vehicle or mount: one per seat, with entry/exit points, occupant handling and access rules. Occupancy replicates.
• Pawn Swap Profile (UPawnSwapPawnComponent), optional, on any pawn: roster tag, team, auto registration, interaction switching and per-pawn overrides (blend, controller policy, input).
• PawnSwap Library (UPawnSwapLibrary): seats of a vehicle, occupants, team lookups, capsule tests.

The 15 features:

1. Swap manager that possesses another pawn on request.
2. Smooth view-target blend on every switch (time, function, exponent, lock outgoing).
3. Roster of switchable pawns: next / previous / index / tag.
4. Seat component with entry and exit points.
5. Multiple seats per vehicle: driver / passenger, occupancy, possess the vehicle from the driver seat.
6. Exit location validation with capsule tests and a fallback search.
7. Controller policy for the pawn left behind.
8. Seated occupant handling: attach, hide, collision, movement, restore.
9. Interaction query for "Press E to enter" prompts.
10. Seat locking and access rules.
11. Events for switches, seats and denials (with a reason enum).
12. Multiplayer: Server RPCs and replicated occupancy with RepNotify.
13. Spectate mode without possessing.
14. Input mode per pawn and a Setup Input event.
15. Save / restore of roster and seat occupancy.

Requirements

Installation

1. Install PawnSwap from Fab into your engine, or copy the PawnSwap folder into your project's Plugins folder.
2. Enable PawnSwap in Edit > Plugins and restart the editor.
3. C++ only: add PublicDependencyModuleNames.Add("PawnSwap"); to your Build.cs.

Quick start

1. Open your PlayerController Blueprint and add a Pawn Swap Manager component.
2. Place two characters in the level. On the second one add a Pawn Swap Profile and tick Auto Register (player index 0). The first pawn you possess is registered automatically (Register Initial Pawn).
3. In the PlayerController, bind a key (Tab) to Switch To Next. Play: Tab blends the camera to the other character and gives you control.
4. Open a vehicle Blueprint (any pawn, for example a wheeled vehicle), make sure Replicates is on, add a Pawn Swap Seat under the body where the driver sits. Keep Seat Role on Driver. Add a scene component DoorLeft beside the door and add an Entry Point with Component = DoorLeft.
5. Bind a key (E) to Interact on the manager. Walk to the door and press E: the character sits in the seat and you drive the vehicle. Press E again to get out at the door (or the nearest free spot).

1. Swap manager

Component UPawnSwapManagerComponent — displayed as Pawn Swap Manager. Add it to the PlayerController (an AIController also works for server-side switching without camera or input). It replicates; every request made on a client is sent to the server.

A switch is refused when the target is invalid, already controlled, controlled by another player, not allowed by the roster rule, or requested during the cooldown; see Events.

2. Camera blend

struct FPawnSwapBlendSettings — used by Switch Blend (switching), Seat Blend (entering a driver seat / leaving it) and Spectate Blend.

Manage Camera (default on) holds the PlayerController's Auto Manage Active Camera Target during the possession so the engine does not cut the view, then restores it and starts the blend. On a remote client the hold and the blend are sent on the controller's reliable channel in order. A Pawn Swap Profile can override the blend for switches to its pawn (Override Blend).

3. Roster

The roster is the ordered list of pawns a player can switch between. It is kept on the server and replicated to the owning client.

Pawns can also register themselves with a Pawn Swap Profile (Auto Register, Auto Register Player Index; -1 = every player). Destroyed pawns are removed automatically.

4. Seats & points

Component UPawnSwapSeatComponent — displayed as Pawn Swap Seat. A scene component: its transform is where the occupant sits. The vehicle actor must replicate.

struct FPawnSwapSeatPoint — an entry or exit point: Component (name of a scene component of the vehicle, None = the seat itself) plus an Offset transform relative to it. The offset rotation sets the facing after an exit.

Point helpers: Get Point Transform, Get Entry Transforms, Get Exit Transforms, Get Nearest Entry Location. Manager nodes: Enter Seat (Seat), Exit Seat, Get Current Seat, Is Seated.

5. Multi-seat vehicles

Add one Pawn Swap Seat per seat. Seats of the same actor form the vehicle.

6. Exit validation

Find Exit Transform (For Pawn) is used by every exit. It uses the pawn's capsule (character capsule, capsule root, collision cylinder, else the defaults) and tries, in order:

1. Each exit point (or entry point): snapped to the ground below, tested with a capsule overlap and a line of sight from the seat (the vehicle itself is ignored for the sight test).
2. Fallback rings around the vehicle bounds, starting on the side of the seat and alternating left/right.
3. The roof of the vehicle.

If nothing is free the exit is refused with Exit Blocked and the occupant stays seated. struct FPawnSwapExitSettings (seat property Exit Settings):

Library: Is Capsule Free and Get Pawn Collision Size for your own placement checks.

7. Left-behind pawns

enum EPawnSwapLeftBehind decides what happens to the controller of the pawn you leave:

Used by the manager's Left Behind Policy (default Leave Unpossessed), a profile's Left Behind Policy when Override Left Behind is on (profile default Spawn AI Controller), and the seat's Vehicle On Exit for the vehicle a driver leaves (default Leave Unpossessed). A driver who switches away keeps sitting in the vehicle, which stays unpossessed; switching back to that pawn resumes driving.

8. Seated occupant

The previous state (collision, visibility, movement, controller rotation flags) is stored when the pawn sits down and restored when it leaves; the pawn is detached and stood upright. The same handling runs on every machine through the occupancy RepNotify, so collision and movement are correct on clients too.

9. Interaction query

Find Best Interaction returns an struct FPawnSwapInteraction: Type (None, Seat, Pawn, Exit), Seat, Pawn, Distance, View Angle, Prompt and Deny Reason. While seated it returns Exit. Interact runs the best one (enter, take over, exit); Interact With runs a given result.

Settings (Interaction, FPawnSwapInteractionSettings):

Auto Scan Interaction (default off) queries every Scan Interval seconds (default 0.1) on the owning client and fires event On Interaction Changed when the target changes; Get Current Interaction returns the last result.

10. Locks & access

Set Seat Owner (server) accepts a controller, player state or pawn; Get Seat Owner reads it. A pawn's team is its profile Team Id when 0 or more, otherwise the manager's Team Id (default 0, set with Set Team Id on the server). Check Access (Candidate, Controller) returns the deny reason without entering. Override event Check Custom Access in a seat subclass for keys, factions or quest state (refused with Custom Rule).

11. Events

Manager switch, seat and deny events fire on the server and on the owning client (once in standalone and on a listen-server host). enum EPawnSwapDenyReason: None, Invalid Target, No Pawn, No Authority, Locked, Not Owner, Wrong Team, Occupied, Out Of Range, Already Seated, Not Seated, Exit Blocked, Controlled By Other Player, Not In Roster, Already Controlled, Cooldown, Custom Rule.

12. Multiplayer

• Switch, enter, exit and change-seat calls made on a client go to the server with reliable Server RPCs; the server validates everything (roster, access, range, exit space) and answers through the events.
• Seat Occupant replicates with a RepNotify that attaches/detaches and applies/restores the occupant state on every client; lock, access rule, team and owner replicate too.
• The roster, the current seat and the team id replicate to the owning client only.
• Camera blends reach remote clients through the engine's view-target replication; the manager holds the client's automatic camera during the possession so the blend is not cut.
• After an exit the server teleports the pawn and sends the owning client its new location.

13. Spectate

Spectating is a view change on the owning client (the server keeps you possessing your pawn). Ignore Input While Spectating (default on) blocks move and look input until you return; any possession change ends spectating.

14. Input per pawn

struct FPawnSwapInputSettings — applied on the owning client after every switch: the new pawn's profile Input when Override Input is on, else the manager's Default Input.

Then event Setup Input For Pawn (overridable in a manager subclass) and event On Setup Input fire: add input mapping contexts, bind actions or show the pawn's HUD there. Apply Input Settings applies a settings struct at any time.

15. Save / restore

Export State returns struct FPawnSwapSaveData (all fields marked SaveGame): Pawns (actor name, roster tag, class, transform), Active Index (your pawn, or the driver while driving) and Seats occupied by roster pawns (vehicle name/tag, seat name, occupant index, driving, locked). Store it in your SaveGame object.

Restore State (Data, Restore Transforms, Spawn Missing) on the server: frees the seats held by your pawns, finds each pawn by Roster Tag (profile tag or first actor tag) or by actor name, respawns missing ones from their class when Spawn Missing is on, moves them when Restore Transforms is on, rebuilds the roster, re-seats the occupants, restores seat locks and possesses the active pawn (or its vehicle when it was driving). Both default to on.

Pawn Swap Profile

Component UPawnSwapPawnComponent — displayed as Pawn Swap Profile. Optional, on any pawn.

Blueprint library

Function Library UPawnSwapLibrary — category PawnSwap.

C++

#include "PawnSwapManagerComponent.h"
#include "PawnSwapSeatComponent.h"
#include "PawnSwapLibrary.h"

// In your PlayerController
UPROPERTY(VisibleAnywhere)
UPawnSwapManagerComponent* Swap;

AMyPlayerController::AMyPlayerController()
{
    Swap = CreateDefaultSubobject<UPawnSwapManagerComponent>(TEXT("Swap"));
    Swap->SwitchBlend.BlendTime = 0.4f;
    Swap->LeftBehindPolicy = EPawnSwapLeftBehind::SpawnAIController;
    Swap->bAutoScanInteraction = true;
}

void AMyPlayerController::OnInteractPressed()  { Swap->Interact(); }
void AMyPlayerController::OnNextPressed()      { Swap->SwitchToNext(); }

// AI passenger (server)
if (UPawnSwapSeatComponent* Seat = UPawnSwapLibrary::GetFreeSeat(Bus, Npc, false))
{
    Seat->SeatPawn(Npc);
}

// Save game
MySave->Swap = Swap->ExportState();
Swap->RestoreState(MySave->Swap, true, true);

Troubleshooting

Credits

© 2026 Alpha XP — alphaxp.net · Support: support@alphaxp.net. Built for Unreal Engine 4.27 and 5.8.