Introduction

Character Interaction System lets a character use things in the world: doors, gates, levers, buttons, crates, hand scanners, pickups and code locks. You set up an object in the Details panel: the sides it can be used from, the states it has, how the character moves to it and what happens when it is used. The same setup works in single player and online: by default, the server checks every use a client asks for, and the use runs on the user’s machine, on the server and on every client that shows it.

What’s in the box

System	What it does	Main type
Character interaction component	Goes on the character: finds the objects in reach, picks the one to use and runs the hold and the use.	UCISCharacterInteractionComponent
Interaction object component	Makes an actor usable: the sides it is used from, its state as a gameplay tag, and what each side does in each state.	UCISInteractionObjectComponent
Actions	What a use does, such as playing a montage or picking up an item. A finished Action can set the object's next state.	UCISInteractionObjectAction
Move handlers	Bring the character into place before or while the Action runs.	UCISInteractionObjectMoveHandler
Conditions	Decide whether a character may use an object. The server can check them again before it accepts a use.	UCISInteractionObjectCondition
Choosing the object	Tests that score the objects in reach, so the character uses the best one.	UCISDetermineUseObjectTest
Data objects	Link one character to one object it can use: the side it uses and Blueprint events at each stage of a use.	UCISInteractionDataObject
Widgets and icons	Show an object's icon on screen with the widget component and the plugin's widgets.	UCISWidgetComponent
Component references	Name a component of an actor, and a socket, in the Details panel; the plugin finds it at run time.	FCISSceneComponentsOnActor
Animation helpers	Attach a mesh to a socket for the length of an anim notify, and move a character with root motion.	UCISAnimNotifyStateAttachMesh
Multiplayer	Where Actions and MoveHandlers run, how the server checks a use, and the project's network settings.	ECISNetExecutionPolicy

How it fits into your game

• Add UCISCharacterInteractionComponent to your character. It tracks the interaction objects near the character through trigger components and picks the one to use with tests such as UCISDetermineUseObjectTest. Call UCISCharacterInteractionComponent::TryUseObject when the player presses the use button: the use starts once the button has been held for the use time, set on the character or per object.
• Add UCISInteractionObjectComponent to any actor that can be used. It holds the sides the object can be used from. Each side has an angle range, a MoveHandler that brings the character into place, and an Action for each state of the object; the state is a gameplay tag.

The demo in /CharacterInteractionSystem/Demo has a character and ready objects built this way.

Modules

Module	Type	What it holds
CharacterInteractionSystem	Runtime	Everything a game uses: the components, Actions, MoveHandlers, Conditions, tests and settings.
CharacterInteractionSystemEditor	Editor	The Details panel pickers for component references: a component of the actor and its socket.

Next

• Installation: engine version, platforms and how to add the plugin to a project.
• Upgrading from 1.x: what changes for a project made with 1.x.