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> Unreal Engine API Reference > Plugins > ModelingComponents > Selection > UPolygonSelectionMechanic

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UPolygonSelectionMechanic

[UPolygonSelectionMechanic](API\Plugins\ModelingComponents\Selection\UPolygonSelectionMechanic) implements the interaction for selecting a set of faces/vertices/edges from a [FGroupTopology](API\Plugins\DynamicMesh\FGroupTopology) on a [USimpleDynamicMeshComponent](API\Plugins\ModelingComponents\USimpleDynamicMeshComponent).

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Inheritance Hierarchy

UObjectBase

UObjectBaseUtility

UObject

UInteractionMechanic

UPolygonSelectionMechanic

References

Module	ModelingComponents
Header	/Engine/Plugins/Experimental/MeshModelingToolset/Source/ModelingComponents/Public/Selection/PolygonSelectionMechanic.h
Include	#include "Selection/PolygonSelectionMechanic.h"

Syntax

[UCLASS](Programming/UnrealArchitecture/Reference/Classes#classdeclaration)()
class UPolygonSelectionMechanic : public UInteractionMechanic

Remarks

UPolygonSelectionMechanic implements the interaction for selecting a set of faces/vertices/edges from a FGroupTopology on a USimpleDynamicMeshComponent.

Variables

	Name	Description
TUniquePtr< FPo...	ActiveChange
bool	bAddSelectionFilterPropertiesToParentTool	Configuration variables that must be set before bSetup is called
FViewCameraStat...	CameraState
TSet< int >	CurrentlyHighlightedGroups
UTriangleSetCom...	DrawnTriangleSetComponent
TFunction< bool...	GetAddToSelectionModifierStateFunc
TFunction< FDyn...	GetSpatialFunc
UMaterialInterf...	HighlightedFaceMaterial
FToolDataVisual...	HilightRenderer
FGroupTopologyS...	HilightSelection
const FDynamicM...	Mesh
FSimpleMulticas...	OnSelectionChanged	OnSelectionChanged is broadcast whenever the selection is modified (including by FChanges)
FGroupTopologyS...	PersistentSelection
FToolDataVisual...	PolyEdgesRenderer
APreviewGeometr...	PreviewGeometryActor	The actor we create internally to own the DrawnTriangleSetComponent
UPolygonSelecti...	Properties
FToolDataVisual...	SelectionRenderer
int32	SelectionTimestamp
TFunction< bool...	ShouldSelectEdgeLoopsFunc	When bSelectEdgeLoops is true, this function is tested to see if we should select edge loops, to allow edge loop selection to be toggled with some key (setting bSelectEdgeLoops to false overrides this function).
TFunction< bool...	ShouldSelectEdgeRingsFunc	When bSelectEdgeRings is true, this function is tested to see if we should select edge rings, to allow edge ring selection to be toggled with some key (setting bSelectEdgeRings to false overrides this function).
FTransform3d	TargetTransform
const FGroupTop...	Topology
FGroupTopologyS...	TopoSelector

Destructors

	Name	Description
	~UPolygonSelectionMechanic()

Functions

	Name	Description
void	BeginChange()	Change Tracking Begin a change record.
void	ClearHighlight()	Clear current hover-highlight
void	ClearSelection()	Clear the current selection
TUniquePtr< ...	EndChange()	End the active change and return it. Returns empty change if the selection was not modified!
bool	EndChangeAndEmitIfModified()	Ends the active change and emits it via the parent tool, if the selection has been modified.
const FGroup...	GetActiveSelection()
FFrame3d	GetSelectionFrame ( bool bWorld, FFrame3d* InitialLocalFrame )
FGroupTopolo...	GetTopoSelectorSettings ( bool bUseOrthoSettings )	Get the topology selector settings to use given the current selection settings.
bool	HasSelection()
void	Initialize ( const FDynamicMesh3* Mesh, FTransform TargetTransform, UWorld* World, const FGroupTopology* Topology, TFunction< FDynamicMeshAABBTree3&#..., TFunction< bool)> GetAddToSele... )	Initializes the mechanic.
void	Initialize ( USimpleDynamicMeshComponent* M..., const FGroupTopology* Topology, TFunction< FDynamicMeshAABBTree3&#..., TFunction< bool)> GetAddToSele... )
void	NotifyMeshChanged ( bool bTopologyModified )	Notify internal data structures that the associated MeshComponent has been modified.
void	SetSelection ( const FGroupTopologySelection& Sel... )	Replace the current selection with an external selection.
void	SetShouldSelectEdgeLoopsFunc ( TFunction< bool)> Func )
void	SetShouldSelectEdgeRingsFunc ( TFunction< bool)> Func )
bool	TopologyHitTest ( const FRay& WorldRay, FHitResult& OutHit, bool bUseOrthoSettings )	Perform a hit test on the topology using the current selection settings.
bool	TopologyHitTest ( const FRay& WorldRay, FHitResult& OutHit, FGroupTopologySelection& OutSelect..., bool bUseOrthoSettings )	Perform a hit test on the topology using the current selection settings.
bool	UpdateHighlight ( const FRay& WorldRay )	Hover API Update the hover highlight based on the hit elements at the given World Ray
bool	UpdateSelection ( const FRay& WorldRay, FVector3d& LocalHitPositionOut, FVector3d& LocalHitNormalOut )	Selection API Intersect the ray with the mesh and update the selection based on the hit element, modifier states, etc

Overridden from UInteractionMechanic

	Name	Description
void	Render ( IToolsContextRenderAPI* Render... )	Allow the Mechanic to do any custom drawing (ie via PDI/RHI)
void	Setup ( UInteractiveTool* ParentTool )	Called to initialize the InteractionMechanic
void	Shutdown()	Called to clean up the InteractionMechanic

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