User Guide

Purpose

NsInteraction lets an actor, usually the player, use other actors: doors, levers, pickups, and buttons. A sensor gives the targets. The interaction component asks each target for its option, keeps the best one, and runs it on a press or at the end of a hold.

NsInteraction has no UI and no input binding. Your game shows the prompt and calls the component from its input. NsInteraction depends on no other plugin.

Setup

1. Copy the NsInteraction folder into the Plugins folder of your project.
2. Open the project and enable NsInteraction in Edit > Plugins.
3. For C++, add "NsInteraction" to the dependencies of your game module in Build.cs.
4. Restart the editor.

The plugin has no project settings.

Quick Start

1. Make a Blueprint class with the parent NsInteractableActor. Name it BP_Button.
2. Add a Static Mesh component to BP_Button and set a mesh. Its collision must block the Visibility channel.
3. In the Event Graph, implement On Interact and add a Print String node.
4. Place BP_Button in the level.
5. Open your player pawn. Make sure that it has a Camera component.
6. Add the Ns Interaction component and the Ns Interaction View Sensor component to the pawn.
7. In the input of the pawn, call Begin Interact on the Ns Interaction component when the input starts.
8. Call End Interact when the input ends.
9. Press Play, look at the button from less than 3 m, and press the input. The text prints.

In C++, implement INsInteractable on any actor:

// MyLever.h
#include "GameFramework/Actor.h"
#include "NsInteractable.h"
#include "MyLever.generated.h"

UCLASS()
class AMyLever : public AActor, public INsInteractable
{
    GENERATED_BODY()

public:
    virtual bool GetInteractionOption_Implementation(AActor* Interactor, UPrimitiveComponent* Part, FNsInteractionOption& OutOption) override
    {
        OutOption.Prompt = NSLOCTEXT("MyGame", "PullLever", "Pull the lever");
        return true;
    }

    virtual bool ExecuteInteraction_Implementation(AActor* Interactor, const FNsInteractionOption& Option) override
    {
        bPulled = !bPulled;
        return true;
    }

    bool bPulled = false;
};

Common Tasks

Make an interactable with no code

1. Make a Blueprint class with the parent NsInteractableActor.
2. Add the meshes. Each mesh that takes the aim must block the trace channel of the view sensor.
3. In the Details panel, open Interaction > Option.
4. Set Prompt, Title, Input, and the other fields.
5. Implement On Interact, or bind On Interacted.

The default option has Action Id Use, Prompt “Use”, and Authority Server. To turn the option on or off in play, call Set Interaction Enabled.

Make any Blueprint interactable

1. Open the Blueprint and select Class Settings.
2. Under Interfaces, add NsInteractable.
3. Implement Get Interaction Option. Set the fields of Out Option and return true.
4. Implement Execute Interaction. Read Action Id from the option and run the action.
5. Optional: implement On Interactor Enter and On Interactor Exit to react when an interactor starts or stops to consider the actor.

Return false from Get Interaction Option when the part has no action now. Do not change game state in it, because the component calls it often.

Aim at targets

1. Add the Ns Interaction View Sensor component to the pawn.
2. Make sure that the pawn has a Camera component, or call Set View Source with another scene component.
3. Set Trace Distance Cm to the reach of the aim.

The sensor uses the first camera of the owner and the first Ns Interaction component of the owner. It traces each frame on the machine that controls the pawn.

Use nearby targets

1. Add a Sphere Collision or Box Collision component to the pawn.
2. On its On Component Begin Overlap event, call Handle Sensor Begin Overlap on the Ns Interaction component. Pass all pins.
3. On its On Component End Overlap event, call Handle Sensor End Overlap the same way.

In C++, bind the overlap delegates to UNsInteractionComponent::HandleSensorBeginOverlap and HandleSensorEndOverlap with AddDynamic.

Give targets from game code

1. Call Add Target with an actor and an optional part.
2. Call Remove Target with the actor to remove all of its targets.
3. Call Set Targets to replace the full list. The first target wins a tie.

Show a prompt

1. Bind On Option Changed on the Ns Interaction component.
2. When Has Option is true, show Title and Prompt of the option at Prompt Location.
3. When Has Option is false, hide the prompt.
4. For a hold, read Get Hold Progress each frame. It goes from 0 to 1.

Hold to interact

1. Set Input of the option to Hold.
2. Set Hold Seconds to the hold time.
3. Optional: set Tap Action Id to run another action on a short press.

The action runs when the hold time ends. A release before the end runs the tap action, when it is set. The hold stops when the target changes.

Offer more than one action

1. Give each part of the actor its own option in Get Interaction Option. The Part input names the part that the sensor found.
2. Give each option its own Action Id.
3. In Execute Interaction, run the action that Action Id names.

Show an action that is not available

1. Set Enabled of the option to false.
2. Put the reason in Prompt.

The prompt shows, and the input runs nothing.

Run an action on the server

1. Set Authority of the option to Server.
2. Keep Send Server Requests on the Ns Interaction component on.
3. Set Max Distance Cm on the Ns Interaction component, so the server checks the reach.

On a client, the component fires On Server Request and sends the request to the server. The server builds the option again and runs it when the option is enabled and names the same action. The pawn must belong to the player controller of the client.

To send the request yourself, clear Send Server Requests. Bind On Server Request, send the target and the action in your own server RPC, and call Execute On Server there. You can check the aim first with Is Part In View on the view sensor.

Make the aim forgiving

1. Set Assist Angle Deg on the view sensor, for example to 8.
2. Keep Assist Stick Deg at 2 or more, so two close parts do not flicker.

When the exact aim gives no option, the part nearest to the view direction inside the cone takes the focus.

Change which option wins

1. Make a child class of the Ns Interaction component.
2. Override Score Option. The highest score wins.

The default score prefers a higher Priority, then a nearer target.

Settings

Ns Interaction component

Ns Interaction View Sensor component

Interaction option

On Ns Interactable Actor, the option defaults are Action Id Use, Prompt “Use”, and Authority Server.

Debug

The plugin has no console commands, console variables, log category, or debug draw.

To see the state in play, print these values:

• Get Targets, Has Option, and Get Option on the Ns Interaction component.
• Get Focus on the Ns Interaction View Sensor component.

Troubleshooting

Limits

• The option of Ns Interactable Actor does not replicate. Set Interaction Enabled changes it only on the machine that calls it.
• One option for each target at a time. For two actions on one part, change the option, or use two parts.
• The view sensor gives one target at most.
• The aim assist measures the bounds box of a part, not its exact shape.
• The built-in server request checks the reach and the option, but not the aim of the client.

Contact

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