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Physics Asset Properties Reference

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This page contains a reference listing of properties for Physics Asset Tool, separated into 3 expandable sections based on what is selected in the viewport.

Physics Asset Tool Properties

When no Physics Body or Physics Constraint is selected (regardless of mode), the properties for the Physics Asset Tool are show in the Details panel.

Anim

PhATDef1.png

Property

Description

Physics Blend

Enables you to manually control the physics/animation blend while simulating in the Physics Asset Tool.

Update Joints from Animation

Let's you manually control the physics/animation.

Physics Update Mode

Determines whether simulation of root body updates component transform.

Value

Description

Simulation Updates Component Transfrom

Simulation updates the component's transform.

Component Trasform is Kinematic

Simulation doesn't update the component's transform. Instead it is driven by animation, blueprint, etc...

Poke Pause Time

Time between poking a ragdoll and starting to blend back.

Poke Blend Time

Time taken to blend from physics to animation.

Simulation

PhATDef2.png

Property

Description

Floor Gap

The gap between the floor and physics objects in the Physics Asset Tool. Changing this requires a restart of the Physics Asset Tool.

Grav Scale

Scale factor for the gravity used in the simulation while in the Physics Asset Tool.

Max FPS

Max FPS for simulation in PhAT. This is helpful for targeting the same FPS as your game. -1 means this is disabled.

Time Dilation

This will dilate the time by scale.

Mouse Spring

PhATDef3.png

Property

Description

Handle Linear Damping

Linear damping of mouse spring forces.

Handle Linear Stiffness

Linear stiffness of mouse spring forces.

Handle Angular Damping

Angular damping of mouse spring forces.

Handle Angular Stiffness

Angular stiffness of mouse spring forces.

Interpolation Speed

How quickly we interpolate the physics target transform for mouse spring forces.

Poking

PhATDef4.png

Property

Description

Poke Strength

Strength of the impulse used when poking with the left mouse button.

Advanced

PhATDef5.png

Property

Description

Show Constraints as Points

Whether or not to draw constraints as points.

Show Names in Hierarchy

Whether or not to draw bone names in the viewport.

Drawing

PhATDef6.png

Property

Description

Constraint Draw Size

Controls how large constraints are drawn in the Physics Asset Tool.

Body Mode Properties

When the Physics Asset Tool is in Body Mode and a Physics Body is selected, the Details panel will display the properties for that Physics Body.

Physics

PhATBody2.png

Property

Description

Mass in KG

Mass of the body in KG.

Linear Damping

"Drag" force added to reduce linear movement.

Angular Damping

"Drag" force added to reduce angular movement.

Enable Gravity

If object should have the force of gravity applied.

Physics Type

If this is set to Simulated it will use physics. If this is set to Kinematic it will use kinematic. Default will inherit from OwnerComponent's behavior.

Double Sided Geometry

If true, the physics triangle mesh will use double sided faces when doing scene queries. Thsi is useful for planes and single sided meshes that need traces to work on both sides.

Simple Collision Physical Material

The Physical Material to use for simple collision on this body.

Advanced

PhATBody2_adv.png

Property

Description

Start Awake

If the physics body should start awake (and moving), or asleep (stationary until interacted with).

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.

Generate Wake Events

Should wake/sleep events fire when this object is woken up or put to sleep by the physics simulation.

Max Depenetration Velocity

The maximum velocity used to depenetrate this object.

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). Determines how the Walkable Slope Angle operates on the existing walkable angle, whether it increases or decreases it.

Walkable Slope Angle

Override walkable slope, applying the rules of the Walkable Slope Behavior.

Custom Sleep Threshold Multiplier

If the SleepFamily is set to custom, multiply the natural sleep threshold by this amount. A higher number will cause the body to sleep sooner.

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.

Sleep Family

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

Body Setup

PhATBody1.png

Property

Description

Primitives

The basic shapes that compose this Bone's collision.

Bone Name

Used in the PhysicsAsset case, associates this Body with a Bone in a Skeletal Mesh.

Consider for Bounds

Should this bone be used in the calculation for the bounding volume of the Skeletal Mesh.

Collision

PhATBody3.png

Property

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.

Collision Response

See the Collision Response Reference documentation for more information.

Advanced

PhATBody3_adv.png

Property

Description

Use CCD

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

Physical Animation

PhATBody4.png

Please see the Physics Asset Tool How-To Landing Page for more information on using Physical Animations.

Constraint Mode Properties

When the Physics Asset Tool is in Body Mode and a Physics Body is selected, the Details panel will display the properties for that Physics Body.

Constraint

PhATCon1.png

Property

Description

Joint Name

The name of the bone (Physics Body) this Physics Constraint is associated with.

Constraint Bone 1

Name of the first bone (Physics Body) this Physics Constraint is connecting. This will be the "child" bone in a Physics Asset.

Constraint Bone 2

Name of the second bone (Physics Body) this Physics Constraint is connecting. This will be the "parent" bone in a Physics Asset.

Linear Limits

propProjection.png

Property

Description

Disable Collision

This disables collision between the constrained components.

Enable Projection

If the distance error between bodies exceeds Projection Linear Tolerance value, or rotational error exceeds Projection Angular Tolerance, the Physics Body will be projected to fix this. This fixes cases where the visuals look disconnected, such as individual chain links breaking away from each other.

Projection Linear Tolerance

If the distance error exceeds this value, in world units, the body will be projected.

Projection Angular Tolerance

If the rotational error exceeds this value, in degrees, the body will be projected.

Projection

propJointPresets.png

Property

Description

Hinge

Setup joint as hinge. A hinge joint allows motion only in one plane.

Prismatic

Setup joint as prismatic. A prismatic joint allows only linear sliding movement.

Ball and Socket

Setup joint as ball and socket. A Ball and Socket joint allows motion around an indefinite number of axes, which have one common center.

Angular Limits

propLinearLimits.png

Property

Description

XMotion

Indicates the linear constraint applied along the X-axis.

Type

Description

Free

No constraint along this axis.

Limited

Limited freedom along this axis. The limit is defined for all axes by the Linear Limit Size property.

Locked

Fully constraint along this axis.

YMotion

Indicates the linear constraint applied along the Y-axis.

Type

Description

Free

No constraint along this axis.

Limited

Limited freedom along this axis. The limit is defined for all axes by the Linear Limit Size property.

Locked

Fully constraint along this axis.

ZMotion

Indicates the linear constraint applied along the Z-axis.

Type

Description

Free

No constraint along this axis.

Limited

Limited freedom along this axis. The limit is defined for all axes by the Linear Limit Size property.

Locked

Fully constraint along this axis.

Limit

The distance allowed between the two joint reference frames.

Scale Linear Limits

If true, linear limits scale using the absolute min of the 3D scale of the owning component.

Advanced

propLinearLimitsADV.png

Property

Description

Soft Constraint

Whether we want to use a soft constraint (spring).

Stiffness

Stiffness of the soft constraint. Only used when Soft Constraint is on.

Damping

Damping of the soft constraint.

Restitution

Controls the amount of bounce when the constraint is violated.

Contact Distance

Determines how close to the limit we have to get before turning the joint on.

Linear Breakable

Whether it is possible to break the joint with linear force.

Linear Break Threshold

Force needed to break the distance constraint.

Linear Motor

propsAngularLimits.png

Property

Description

Swing 1Motion

Indicates whether the Swing1 limit is used.

Type

Description

Free

No constraint around this axis.

Limited

Limited freedom around this axis. The limit for each Angular Motion is controlled individually by a correspondingly named Limit property: Swing 1Limit Angle, Swing 2Limit Angle, and Twist Limit Angle.

Locked

Fully constraint around this axis.

Swing 2Motion

Indicates whether the Swing2 limit is used.

Type

Description

Free

No constraint around this axis.

Limited

Limited freedom around this axis. The limit for each Angular Motion is controlled individually by a correspondingly named Limit property: Swing 1Limit Angle, Swing 2Limit Angle, and Twist Limit Angle.

Locked

Fully constraint around this axis.

Twist Motion

Indicates whether the Twist limit is used.

Type

Description

Free

No constraint around this axis.

Limited

Limited freedom around this axis. The limit for each Angular Motion is controlled individually by a correspondingly named Limit property: Swing 1Limit Angle, Swing 2Limit Angle, and Twist Limit Angle.

Locked

Fully constraint around this axis.

Swing 1Limit Angle

Angle of movement along the XY Plane.

Twist Limit Angle

Angle of movement along the XZ Plane.

Swing 2Limit Angle

Symmetric angle of roll along the X-axis.

Angular Rotation Offset

Specifies the angular offset between the two frames of reference. By default this limit goes from (-Angle, +Angle).

Advanced

propsAngularLimitsADV.png

Property

Description

Swing Limits

Soft Constraint

Whether we want to use a soft constraint (spring).

Stiffness

Stiffness of the soft constraint. Only used when Soft Constraint is on.

Damping

Damping of the soft constraint.

Restitution

Controls the amount of bounce when the constraint is violated.

Contact Distance

Determines how close to the limit we have to get before turning the joint on.

Twist Limits

Soft Constraint

Whether we want to use a soft constraint (spring).

Stiffness

Stiffness of the soft constraint. Only used when Soft Constraint is on.

Damping

Damping of the soft constraint.

Restitution

Controls the amount of bounce when the constraint is violated.

Contact Distance

Determines how close to the limit we have to get before turning the joint on.

Breakable

Angular Breakable

Whether it is possible to break the joint with angular force.

Angular Break Threshold

Torque needed to break the joint.

Angular Motor

propLinearMotor.png

Property

Description

Position Target

Enables the position linear motor on one or more axes and sets the local position desired.

Strength

How much force to apply to reach the desired position.

Velocity Target

Enables the velocity linear motor on one or more axes and sets the desired velocity.

Strength

How much force to apply to reach the desired velocity.

Advanced

PhysCon_MotorADV.png

Property

Description

Max Force

The force limit of the drive.

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