Physics Bodies Reference

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This page contains a reference listing of properties in the Physics and Collision categories of properties. If you are looking for reference on Collision Responses or Collision Presets please see: Collision Response Reference .

Properties

Below are the properties for Physics Bodies (Body Instances) separated by major category.

Physics

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Property

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Description

Simulate Physics

If true, this body will use simulation. If false, will be 'fixed' (ie kinematic) and move where it is told. For a Skeletal Mesh Component, simulating requires a physics asset setup and assigned on the SkeletalMesh asset. For a Static Mesh Component, simulating requires simple collision to be setup on the StaticMesh asset.

Mass in KG

Mass of the body in KG.

Angular Damping

'Drag' force added to reduce angular movement

Linear Damping

'Drag' force added to reduce linear movement

Enable Gravity

If object should have the force of gravity applied

Constraints

Lock Position

When a Locked Axis Mode is selected, will lock translation on the specified axis

Property

Description

Lock X Translation

Lock translation along the X-axis

Lock Y Translation

Lock translation along the Y-axis

Lock Z Translation

Lock translation along the Z-axis

Lock Rotation

When a Locked Axis Mode is selected, will lock rotation to the specified axis

Property

Description

Lock X Rotation

Lock rotation about the X-axis

Lock Y Rotation

Lock rotation about the Y-axis

Lock Z Rotation

Lock rotation about the Z-axis

Mode

Locks physical movement along specified axis.

Property

Description

Default

Inherits the degrees of freedom from the project settings.

Six DOF

Specifies which axis to freeze rotation and movement along.

YZPlane

Allows 2D movement along the Y-Z plane.

XZPlane

Allows 2D movement along the X-Z plane.

XYPlane

Allows 2D movement along the X-Y plane.

Custom Plane

Allows 2D movement along the plane of a given normal.

None

No constraints.

Advanced

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Property

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Description

Auto Weld

If true and is attached to a parent, the two bodies will be joined into a single rigid body. Physical settings like collision profile and body settings are determined by the root

Start Awake

If object should start awake, or if it should initially be sleeping

Center Of Mass Offset

User specified offset for the center of mass of this object, from the calculated location

Mass Scale

Per-instance scaling of mass

Max Angular Velocity

The maximum angular velocity for this instance

Use Async Scene

If true, this body will be put into the asynchronous physics scene. If false, it will be put into the synchronous physics scene. If the body is static, it will be placed into both scenes regardless of the value of bUseAsyncScene.

Override Max Depenetration Velocity

Whether this body instance has its own custom MaxDepenetrationVelocity

Max Depenetration Velocity

The maximum velocity used to depenetrate this object

Override Walkable Slope on Instance

Whether this instance of the object has its own custom walkable slope override setting.

Walkable Slope Override

Custom walkable slope setting for this body.

See the Walkable Slope documentation for usage information.

Walkable Slope Behavior

Behavior of this surface (whether we affect the walkable slope). @see GetWalkableSlopeBehavior(), SetWalkableSlopeBehavior()

Walkable Slope Angle

Override walkable slope angle (in degrees), applying the rules of the Walkable Slope Behavior. @see GetWalkableSlopeAngle(), SetWalkableSlopeAngle()

Sleep Family

The set of values used in considering when put this body to sleep.

Position Solver Iteration Count

This physics body's solver iteration count for position. Increasing this will be more CPU intensive, but better stabilized.

Velocity Solver Iteration Count

This physics body's solver iteration count for velocity. Increasing this will be more CPU intensive, but better stabilized.

Should Update Physics Volume

Whether or not the cached PhysicsVolume this component overlaps should be updated when the component is moved. @see GetPhysicsVolume()

Collision

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Property

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Description

Simulation Generates Hit Events

Should 'Hit' events fire when this object collides during physics simulation.

Phys Material Override

Allows you to override the PhysicalMaterial to use for simple collision on this body.

Generate Overlap Events

If true, this component will generate overlap events when it is overlapping other components (eg Begin Overlap). Both components (this and the other) must have this enabled for overlap events to occur.

@see Overlap Events @see UpdateOverlaps(), BeginComponentOverlap(), EndComponentOverlap()

Collision Responses

See the Collision Response Reference documentation for more information.

Advanced

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Property

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Description

Use CCD

If true Continuous Collision Detection (CCD) will be used for this component

Always Create Physics State

Indicates if we'd like to create physics state all the time (for collision and simulation). If you set this to false, it still will create physics state if collision or simulation activated. This can help performance if you'd like to avoid overhead of creating physics state when triggers

Multi Body Overlap

If true, this component will generate individual overlaps for each overlapping physics body if it is a multi-body component. When false, this component will generate only one overlap, regardless of how many physics bodies it has and how many of them are overlapping another component/body. This flag has no influence on single body components.

Check Async Scene On Move

If true, this component will look for collisions on both physic scenes during movement. Only required if the asynchronous physics scene is enabled and has geometry in it, and you wish to test for collisions with objects in that scene. @see MoveComponent()

Trace Complex On Move

If true, component sweeps with this component should trace against complex collision during movement (for example, each triangle of a mesh). If false, collision will be resolved against simple collision bounds instead. @see MoveComponent()

Return Material On Move

If true, component sweeps will return the material in their hit result. @see MoveComponent(), FHitResult

Can Ever Affect Navigation

Whether this component can potentially influence navigation