- Qt 5.15
- Qt 3D
- C++ Classes
- QPickingSettings
- Qt 5.15.11 Reference Documentation

# QPickingSettings Class

class Qt3DRender::QPickingSettings

The QPickingSettings class specifies how entity picking is handled. More...

Header: | #include <QPickingSettings>
qmake: | QT += 3drender
Since: | Qt 5.7
Instantiated By: | PickingSettings
Inherits: | Qt3DCore::QNode

This class was introduced in Qt 5.7.

- List of all members, including inherited members

## Public Types

enum | FaceOrientationPickingMode { FrontFace, BackFace, FrontAndBackFace }
enum | PickMethod { BoundingVolumePicking, TrianglePicking, LinePicking, PointPicking, PrimitivePicking }
enum | PickResultMode { NearestPick, AllPicks, NearestPriorityPick }

## Properties

- faceOrientationPickingMode : FaceOrientationPickingMode
- pickMethod : PickMethod
- pickResultMode : PickResultMode
- worldSpaceTolerance : float

## Public Functions

FaceOrientationPickingMode | faceOrientationPickingMode() const
PickMethod | pickMethod() const
PickResultMode | pickResultMode() const
float | worldSpaceTolerance() const

## Public Slots

void | setFaceOrientationPickingMode(FaceOrientationPickingMode faceOrientationPickingMode)
void | setPickMethod(PickMethod pickMethod)
void | setPickResultMode(PickResultMode pickResultMode)
void | setWorldSpaceTolerance(float worldSpaceTolerance)

## Signals

void | faceOrientationPickingModeChanged(QPickingSettings::FaceOrientationPickingMode faceOrientationPickingMode)
void | pickMethodChanged(QPickingSettings::PickMethod pickMethod)
void | pickResultModeChanged(QPickingSettings::PickResultMode pickResult)
void | worldSpaceToleranceChanged(float worldSpaceTolerance)

## Detailed Description

The picking settings determine how the entity picking is handled. For more details about entity picking, see QObjectPicker and QRayCaster component documentation.

When using QObjectPicker components, picking is triggered by mouse events.

When using QRayCaster or QScreenRayCaster components, picking can be explicitly triggered by the application.

In both cases, a ray will be cast through the scene to find geometry intersecting the ray.

See also QObjectPicker, QPickEvent, QPickTriangleEvent, QRayCaster, and QScreenRayCaster.

## Member Type Documentation

### enum QPickingSettings::FaceOrientationPickingMode

Specifies how face orientation affects triangle picking

Constant | Value | Description
--- | --- | ---
`Qt3DRender::QPickingSettings::FrontFace` | `0x01` | Only front-facing triangles will be picked (default).
`Qt3DRender::QPickingSettings::BackFace` | `0x02` | Only back-facing triangles will be picked.
`Qt3DRender::QPickingSettings::FrontAndBackFace` | `0x03` | Both front- and back-facing triangles will be picked.

### enum QPickingSettings::PickMethod

Specifies the picking method.

Constant | Value | Description
--- | --- | ---
`Qt3DRender::QPickingSettings::BoundingVolumePicking` | `0x00` | An entity is considered picked if the picking ray intersects the bounding volume of the entity (default).
`Qt3DRender::QPickingSettings::TrianglePicking` | `0x01` | An entity is considered picked if the picking ray intersects with any triangle of the entity's mesh component.
`Qt3DRender::QPickingSettings::LinePicking` | `0x02` | An entity is considered picked if the picking ray intersects with any edge of the entity's mesh component.
`Qt3DRender::QPickingSettings::PointPicking` | `0x04` | An entity is considered picked if the picking ray intersects with any point of the entity's mesh component.
`Qt3DRender::QPickingSettings::PrimitivePicking` | `TrianglePicking | LinePicking | PointPicking` | An entity is considered picked if the picking ray intersects with any point, edge or triangle of the entity's mesh component.

### enum QPickingSettings::PickResultMode

Specifies what is included into the picking results.

Constant | Value | Description
--- | --- | ---
`Qt3DRender::QPickingSettings::NearestPick` | `0` | Only the nearest entity to picking ray origin intersected by the picking ray is picked (default).
`Qt3DRender::QPickingSettings::AllPicks` | `1` | All entities that intersect the picking ray are picked.
`Qt3DRender::QPickingSettings::NearestPriorityPick` | `2` | Selects the entity whose object picker has the highest value. If several object pickers have the same priority, the closest one on the ray is selected.

See also Qt3DRender::QPickEvent.

## Property Documentation

### faceOrientationPickingMode : FaceOrientationPickingMode

Specifies how face orientation affects triangle picking

Access functions:

FaceOrientationPickingMode | faceOrientationPickingMode() const
void | setFaceOrientationPickingMode(FaceOrientationPickingMode faceOrientationPickingMode)

Notifier signal:

void | faceOrientationPickingModeChanged(QPickingSettings::FaceOrientationPickingMode faceOrientationPickingMode)

### pickMethod : PickMethod

Holds the current pick method.

By default, for performance reasons, ray casting will use bounding volume picking. This may however lead to unexpected results if a small object is englobed in the bounding sphere of a large object behind it.

Triangle picking will produce exact results but is computationally more expensive.

Access functions:

PickMethod | pickMethod() const
void | setPickMethod(PickMethod pickMethod)

Notifier signal:

void | pickMethodChanged(QPickingSettings::PickMethod pickMethod)

### pickResultMode : PickResultMode

Holds the current pick results mode.

By default, pick results will only be produced for the entity closest to the camera.

When setting the pick method to AllPicks, events will be triggered for all the entities with a QObjectPicker along the ray.

When setting the pick method to NearestPriorityPick, events will be triggered for the nearest highest priority picker. This can be used when a given element should always be selected even if others are in front of it.

If a QObjectPicker is assigned to an entity with multiple children, an event will be triggered for each child entity that intersects the ray.

Access functions:

PickResultMode | pickResultMode() const
void | setPickResultMode(PickResultMode pickResultMode)

Notifier signal:

void | pickResultModeChanged(QPickingSettings::PickResultMode pickResult)

### worldSpaceTolerance : float

Holds the threshold, in model space coordinates, used to evaluate line and point picking.

Access functions:

float | worldSpaceTolerance() const
void | setWorldSpaceTolerance(float worldSpaceTolerance)

Notifier signal:

void | worldSpaceToleranceChanged(float worldSpaceTolerance)

## Member Function Documentation

### `[slot]` void QPickingSettings::setWorldSpaceTolerance(float worldSpaceTolerance)

Sets the threshold used for line and point picking to worldSpaceTolerance.

Note: Setter function for property worldSpaceTolerance.

See also worldSpaceTolerance().

### float QPickingSettings::worldSpaceTolerance() const

Returns the line and point precision worldSpaceTolerance

Note: Getter function for property worldSpaceTolerance.

See also setWorldSpaceTolerance().