PlacementSystemComponent

The PlacementSystemComponent is the core orchestrator of the Grid Placement System plugin. It provides a comprehensive grid-based object placement system with precision controls, multiple surface types, audio feedback, and intuitive interaction methods.

Overview

This component should be added to your Player Pawn to enable grid-based placement functionality. It manages camera controls, input handling, object validation, surface detection, visual feedback, and audio cues during placement mode.

Quick Setup

Add the PlacementSystemComponent to your Player Pawn - all assets and input mappings are auto-loaded from the plugin content.

Configuration Categories

Core Settings

Controls fundamental behavior of the placement system.

Property	Type	Default	Description
Auto Exit After Placement	Boolean	`false`	Automatically exit placement mode after placing an object
Auto Create Grids	Boolean	`true`	Automatically detect and create grids on tagged surfaces when entering placement mode
Default Object To Place	Actor Class	`None`	Object class to select automatically when entering placement mode

Audio

Configure audio feedback for placement actions.

Property	Type	Default	Description
Sounds Enabled	Boolean	`true`	Enable/disable all placement audio feedback
Master Sound Volume	Float	`1.0`	Global volume multiplier for all placement sounds
Snap Sound	Sound Base	Auto-loaded	Sound played when objects snap to grid
Place Sound	Sound Base	Auto-loaded	Sound played when objects are placed
Rotate Sound	Sound Base	Auto-loaded	Sound played when objects are rotated

Grid Settings

Configure the visual grid system and surface detection.

Property	Type	Default	Description
Placement Type Tags	Map	Floor: "Floor" Wall: "Wall" Roof: "Roof"	Tags used to identify different surface types in your level
Grid Size	Float	`25.0`	Size of each grid cell in Unreal units (25 = 25cm)
Grid Color	Linear Color	White	Primary color of the grid lines
Sub Grid Color	Linear Color	White	Color of sub-division grid lines
Grid Pattern	Texture2D	`None`	Optional texture pattern for the grid overlay

Materials

Visual materials used by the placement system (auto-loaded from plugin content).

Property	Type	Default	Description
Grid Material	Material Interface	Auto-loaded	Material applied to surfaces to show the grid
Selected Outline Material	Material Interface	Auto-loaded	Outline material for selected/preview objects
Overlay Material	Material Interface	Auto-loaded	Material for the placement indicator overlay

Object Editing

Settings for editing already-placed objects.

Property	Type	Default	Description
Allow Object Selection	Boolean	`true`	Enable clicking on placed objects to select them for editing
Allow Object Deletion	Boolean	`true`	Allow deleting selected objects with the delete key

Controls

Camera and movement configuration.

Property	Type	Default	Description
Camera Movement Speed	Float	`800.0`	Speed of camera movement during placement
Zoom Speed	Float	`100.0`	Speed of camera zoom in/out
Min Zoom Distance	Float	`200.0`	Minimum camera distance from target
Max Zoom Distance	Float	`1700.0`	Maximum camera distance from target
Object Rotation Increment	Float	`45.0`	Degrees to rotate objects per input (45° = 8 directions)

Precision Placement

Fine-tuned placement controls.

Property	Type	Default	Description
Allow Precision Placement	Boolean	`true`	Enable precision mode when holding Shift
Show Precision Mode Indicator	Boolean	`false`	Hide/Unhide Overlay when in Precision Mode

If you set Show Precision Mode Indicator to false, the Precision Overlay will be hidden.

Visuals

Visual feedback and indicators.

Property	Type	Default	Description
Show Placement Overlay	Boolean	`true`	Show the placement indicator overlay
Valid Placement Color	Linear Color	Green	Color when placement location is valid
Invalid Placement Color	Linear Color	Red	Color when placement location is blocked
Precision Mode Color	Linear Color	White	Color when in precision placement mode

Camera Settings

Camera behavior during placement mode (supports both Third-Person and First-Person setups).

Property	Type	Default	Description
Disable Collision In Placement Mode	Boolean	`true`	Disable camera collision while placing objects
Enable Camera Pitch Constraint	Boolean	`true`	Limit camera pitch to prevent flipping
Min Camera Pitch	Float	`-60.0`	Minimum camera pitch angle (degrees)
Max Camera Pitch	Float	`0.0`	Maximum camera pitch angle (degrees)
Vertical Min Offset Z	Float	`0.0`	Minimum vertical camera offset
Vertical Max Offset Z	Float	`200.0`	Maximum vertical camera offset

Input Settings

Input mapping contexts and actions (auto-loaded from plugin content).

Property	Type	Description
Placement Mapping Context	Input Mapping Context	Context active during placement mode
Toggle Mapping Context	Input Mapping Context	Context for toggling placement mode
IA_Placement Toggle	Input Action	Toggle placement mode on/off
IA_Placement Confirm	Input Action	Confirm object placement
IA_Placement Cancel	Input Action	Cancel placement or exit mode
IA_Placement Rotate	Input Action	Rotate preview object
IA_Placement Zoom	Input Action	Zoom camera in/out
IA_Placement Move	Input Action	Move camera
IA_Placement Shift	Input Action	Hold for precision mode
IA_Select Object	Input Action	Select placed objects for editing
IA_Delete Object	Input Action	Delete selected objects
IA_Placement Vertical	Input Action	Move camera vertically

Debug Settings

Development and debugging tools.

Property	Type	Default	Description
Show Debug Info	Boolean	`false`	Display debug information on screen

Blueprint API

Core Functions

Note: You don't need to use this API unless necessary
PlacementHelper already handles system initialization internally.

Initialize()

UFUNCTION(BlueprintCallable, Category = "GPS: Placement System")
void Initialize();

Initializes the placement system. Call this in your Pawn's BeginPlay event.

StoreInitialCameraState()

UFUNCTION(BlueprintCallable, Category = "GPS: Placement System")
void StoreInitialCameraState();

Stores the initial camera state to restore later when exiting placement mode.

EnterPlacementMode()

UFUNCTION(BlueprintCallable, Category = "GPS: Placement System")
bool EnterPlacementMode();

Enters placement mode. Returns true if successful.

ExitPlacementMode()

UFUNCTION(BlueprintCallable, Category = "GPS: Placement System")
void ExitPlacementMode();

Exits placement mode and returns to normal game mode.

SelectObjectToPlace(ObjectClass)

UFUNCTION(BlueprintCallable, Category = "GPS: Placement System")
bool SelectObjectToPlace(TSubclassOf<AActor> ObjectClass);

Selects an object class for placement. Must be in placement mode first.

ClearSelectedObject()

UFUNCTION(BlueprintCallable, Category = "GPS: Placement System")
void ClearSelectedObject();

Clears the currently selected object for placement.

RefreshGrids()

UFUNCTION(BlueprintCallable, Category = "GPS: Placement System")
void RefreshGrids();

Refreshes the grid system, useful when surfaces are added/removed at runtime.

Object Editing

SelectPlacedObjectForEditing(Actor)

UFUNCTION(BlueprintCallable, Category = "GPS: Object Editing")
void SelectPlacedObjectForEditing(AActor* Actor);

Selects a placed object for editing (moving, rotating, deleting).

DeleteSelectedPlacedObject()

UFUNCTION(BlueprintCallable, Category = "GPS: Object Editing")
void DeleteSelectedPlacedObject();

Deletes the currently selected placed object.

State Getters

GetCurrentMode()

UFUNCTION(BlueprintCallable, BlueprintPure, Category = "GPS: Placement System")
EPlacementMode GetCurrentMode() const;

Returns the current mode: Normal or Placement.

HasSelectedObject()

UFUNCTION(BlueprintCallable, BlueprintPure, Category = "GPS: Placement System")
bool HasSelectedObject() const;

Returns true if an object is selected for placement.

GetCurrentPlacementValidity()

UFUNCTION(BlueprintCallable, BlueprintPure, Category = "GPS: Placement System")
EPlacementValidity GetCurrentPlacementValidity() const;

Returns the current placement validity: Valid, Invalid, or Unknown.

IsInPrecisionMode()

UFUNCTION(BlueprintCallable, BlueprintPure, Category = "GPS: Precision Placement")
bool IsInPrecisionMode() const;

Returns true if precision placement mode is active (Shift held + precision enabled).

Events

Core Placement Events

OnPlacementModeChanged

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnPlacementModeChanged OnPlacementModeChanged;

Fired when entering or exiting placement mode. Parameters: NewMode (EPlacementMode)

OnObjectPlaced

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnObjectPlaced OnObjectPlaced;

Fired when a new object is successfully placed. Parameters: PlacedObject (AActor*), WorldLocation (FVector)

OnPlacementValidityChanged

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnPlacementValidityChanged OnPlacementValidityChanged;

Fired when placement validity changes (valid/invalid/unknown). Parameters: NewValidity (EPlacementValidity)

OnNeedObjectSelection

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnNeedObjectSelection OnNeedObjectSelection;

Fired when the system needs an object to be selected for placement.

Object Management Events

OnPlacedObjectSelected

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnPlacedObjectSelected OnPlacedObjectSelected;

Fired when a placed object is selected for editing. Parameters: SelectedObject (AActor*)

OnPlacedObjectDeselected

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnPlacedObjectDeselected OnPlacedObjectDeselected;

Fired when a placed object is deselected. Parameters: DeselectedObject (AActor*)

OnPlacedObjectMoved

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnPlacedObjectMoved OnPlacedObjectMoved;

Fired when a placed object is moved to a new location. Parameters: MovedObject (AActor*), NewLocation (FVector)

OnPlacedObjectDeleted

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnPlacedObjectDeleted OnPlacedObjectDeleted;

Fired when a placed object is deleted. Parameters: DeletedObject (AActor*)

Tracking and Preview Events

OnObjectClassSelectedForPlacement

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnObjectClassSelectedForPlacement OnObjectClassSelectedForPlacement;

Fired when an object class is selected for placement. Parameters: ObjectClass (TSubclassOf<AActor>), PlacementType (EPlacementType)

OnObjectPreviewStarted

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnObjectPreviewStarted OnObjectPreviewStarted;

Fired when object preview begins (either for new placement or editing). Parameters: PreviewActor (AActor*), ObjectClass (TSubclassOf<AActor>), bIsEditing (bool)

OnObjectPreviewEnded

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnObjectPreviewEnded OnObjectPreviewEnded;

Fired when object preview ends. Parameters: PreviewActor (AActor*)

OnObjectPreviewMoved

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnObjectPreviewMoved OnObjectPreviewMoved;

Fired when the preview object is moved. Parameters: PreviewActor (AActor*), NewLocation (FVector), NewRotation (FRotator)

OnObjectRotated

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnObjectRotated OnObjectRotated;

Fired when an object is rotated during placement. Parameters: PreviewActor (AActor*), OldRotation (float), NewRotation (float)

State Change Events

OnPlacementTypeChanged

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnPlacementTypeChanged OnPlacementTypeChanged;

Fired when switching between Floor/Wall/Roof placement. Parameters: OldType (EPlacementType), NewType (EPlacementType)

OnPrecisionModeChanged

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnPrecisionModeChanged OnPrecisionModeChanged;

Fired when entering or exiting precision mode. Parameters: bPrecisionModeActive (bool)

OnValidationChangedWithContext

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnValidationChangedWithContext OnValidationChangedWithContext;

Enhanced validation event with additional context. Parameters: PreviewActor (AActor*), NewValidity (EPlacementValidity), PlacementType (EPlacementType), bPrecisionMode (bool)

OnInputModeChanged

UPROPERTY(BlueprintAssignable, Category = "GPS: Events")
FOnInputModeChanged OnInputModeChanged;

Fired when input mode state changes. Parameters: bPlacementInputActive (bool), bToggleInputActive (bool)

Surface Setup

To use the placement system, you need to tag your level geometry:

Floor Surfaces: Add the tag Floor to static mesh actors that should accept floor-placed objects
Wall Surfaces: Add the tag Wall to vertical static mesh actors for wall-mounted objects
Roof Surfaces: Add the tag Roof to ceiling/overhead static mesh actors

The system will automatically detect these tagged surfaces and show appropriate grids based on the selected object's placement type.

Default Input Controls

Camera Controls

Input	Action
WASD	Camera Movement
Mouse Scroll	Zoom In/Out
E/Q	Up/Down Movement

Object Placement

Input	Action
Left Click	Place Object
Right Click	Rotate Object
X/ESC	Cancel Placing/Editing Object
Delete	Delete Object While Selected
Middle Mouse	Select Object for Editing

Special Modes

Input	Action
Hold Shift	Precision Mode (bypasses grid snapping)
Tab	Toggle Enter/Exit Placement Mode

Camera System Features

Automatic Camera Setup Detection

Third-Person Projects: Uses existing SpringArm component
First-Person Projects: Automatically creates temporary SpringArm for placement mode
Seamlessly restores original camera setup when exiting placement mode

Camera Constraints

Configurable pitch limits to prevent camera flipping
Collision detection can be disabled during placement
Vertical movement constraints with customizable limits

Performance Considerations

Grid Management: Grids are only shown for the current placement type
Collision Optimization: Uses oriented bounding box collision for accurate placement validation
Audio Throttling: Snap sounds have cooldown to prevent audio spam
Component Architecture: Modular design with dedicated managers for different systems

Audio Feedback System

The system provides audio feedback for key actions:

Snap Sound: Plays when objects snap to grid positions (with cooldown)
Place Sound: Plays when objects are successfully placed
Rotate Sound: Plays when objects are rotated

All sounds respect the master volume setting and can be globally disabled.

Troubleshooting

Objects won't place

Ensure surfaces are tagged correctly (Floor, Wall, Roof)
Check that placement location isn't occupied by other objects
Verify the object implements IPlaceableObjectInterface
Enable debug info to see collision detection visualization

Camera behaves strangely

The system automatically detects and handles both TPP and FPP setups
For FPP projects, a temporary SpringArm is created during placement mode
Check camera pitch constraints if movement feels limited
Verify SpringArm component exists for TPP projects

Grid not showing

Verify Auto Create Grids is enabled
Ensure grid material is assigned (should auto-load from plugin)
Check that surfaces have the correct tags
Call RefreshGrids() if surfaces were added at runtime
Check that the placement type matches the surface tags

Audio not playing

Verify Sounds Enabled is true
Check Master Sound Volume is greater than 0
Ensure audio assets are properly loaded (should auto-load from plugin)
Check that your project's audio settings allow 2D/3D sounds

Performance issues

Disable Show Debug Info in shipping builds
Consider reducing grid density for large surfaces
Limit the number of concurrent preview actors
Use LODs for complex placeable objects

PlacementObjectRegistry DirectionalArrowComponent