Physics Constraint Distance component reference
Physics Constraint Hinge component reference
Physics Constraint Fixed component reference
Explore the properties you can use to keep two connected 2D Physics Core objects at the same position and rotation. For more information, refer to Add a constraint.
Note: This documentation is about using Pose, Area, and Constraint components. To use 2D physics in the Unity Editor using components like the Rigidbody 2D component, refer to 2D physics instead.
Pose
| Property |
Description |
| Pose A Source |
Sets how Unity finds the first object this constraint connects to. The options are:
-
Auto: Searches this GameObject and its parents for a Physics Pose component.
-
Custom: Uses the Physics Pose component you assign to Pose A Target.
|
| Pose A Target |
Sets the first Physics Pose component this constraint connects to. This property is available only if you set Pose A Source to Custom. Drag a GameObject with a Physics Pose component from the Hierarchy window to this property, or select the picker (⊙). |
| Pose B Target |
Sets the second object this constraint connects. Drag a GameObject with a Physics Pose component from the Hierarchy window to this property, or select the picker (⊙). |
| Refresh Poses |
Refreshes Pose A Target and Pose B Target and recreates the constraint. |
Definition
| Property |
Description |
| Definition Asset |
Sets an asset that sets the values of the properties in this section. By default, this property is empty, and Unity stores the values inside the component. To set a definition asset, drag a Physics Constraint Fixed Definition asset from the Project window to this property, or select the picker (⊙). For more information, refer to Share properties across multiple 2D Physics Core components. |
| Linear Frequency |
Sets the stiffness of the spring that tries to keep the positions of the two objects the same, in Hertz (cycles per second). A higher value makes the constraint less stiff. The default is 0. |
| Linear Damping |
Sets how quickly the spring stops pulling or pushing. A higher value makes the constraint settle more quickly. The default is 0. |
| Angular Frequency |
Sets the stiffness of the spring that tries to keep the rotation of the two objects the same, in Hertz (cycles per second). A higher value makes the constraint’s rotation less stiff. The default is 0. |
| Angular Damping |
Sets how quickly the spring stops rotating. A higher value makes the rotation of the constraint settle more quickly. The default is 0. |
| Collide Connected |
Allows the shapes on the two connected objects to collide with each other and create collision or trigger events. By default, the constraint prevents this. For more information, refer to Collisions and interactions in 2D Physics Core. |
Anchors
Set where each end of the constraint attaches. Local Anchor A attaches to the first object and Local Anchor B attaches to the second object. Each anchor has the following properties.
| Property |
Description |
| Auto |
Automatically calculates the anchor position and rotation from the positions of the two objects when Unity creates the constraint. As a result, both anchors line up in world space. |
| Position |
Sets the position of the anchor, relative to the position of the object it attaches to. This property is available only if you disable Auto. |
| Rotation |
Sets the rotation of the anchor in degrees. This property is available only if you disable Auto. |
Thresholds
| Property |
Description |
| Force Threshold |
Sets the amount of linear force that creates an OnJointThreshold2D event. |
| Torque Threshold |
Sets the amount of rotational force that creates an OnJointThreshold2D event. |
Tuning
| Property |
Description |
| Tuning Frequency |
Sets the overall stiffness of the constraint in Hertz (cycles per second). A higher value makes the constraint less stiff. |
| Tuning Damping |
Sets how quickly overall the constraint stops pulling or pushing. A higher value makes the constraint settle more quickly. |
Drawing
Callbacks
| Property |
Description |
| Callback Source |
Sets the callback method the constraint calls when the force or torque exceeds Force Threshold or Torque Threshold. The options are:
|
| Callback Target |
Sets the object that receives physics callbacks. This property is available only if you set Callback Source to Constraint or Joints. |
Event settings
The properties in this section set the specific method this constraint calls or the parameter it sets, and control the behavior of the On Joint Threshold (JointThresholdEvent) method of the component. This section is available only if you set Callback Source to Events.
| Property |
Description |
| Activation |
Sets when the constraint activates the callback method or sets the parameter. The options are:
-
Off: Doesn’t activate the callback method or set the parameter.
-
Editor and Runtime: Activates the callback method or sets the parameter in the Unity Editor and at runtime.
-
Runtime Only: Activates the callback method or sets the parameter only at runtime.
|
| Object |
Sets the object with the method to call or parameter to update. Drag any object from the Hierarchy or Project windows to this property, or select the picker (⊙). |
| Functions |
Sets the parameter to update or the method to call. Select a parameter or method from the Object, its components, or its script methods. You can set the parameter value to update to, or the method parameters to use. |
|
Add (+) |
Adds a new callback method to the list. |
|
Remove (-) |
Removes the selected callback method from the list. |
User Data
Use the properties in this section to add your own data to the component, and read it using the U2D.Physics API. For more information, refer to Add custom data to a 2D Physics Core object.
| Property |
Description |
| Object |
Sets a custom object. Drag any object from the Hierarchy or Project windows to this property, or select the picker (⊙). |
| Physics Mask |
Sets a custom set of enabled and disabled layers. For more information, refer to Configure collisions between 2D Physics Core objects. |
| Float |
Sets a custom floating-point number. |
| Int |
Sets a custom integer. |
| Int 64 |
Sets a custom 64-bit integer. |
| Vector 3 Int |
Sets a custom 3D vector of integers. |
| Bool |
Sets a custom Boolean value. |
Info
This section displays information about the constraint. You can’t directly edit the properties in this section.
Handle
| Property |
Description |
| Valid |
The state of the object. True means the object is in the simulation. |
| World |
The index number of the world the object belongs to. The default is 0, which is the default world. |
| Index |
The index number of the object in the world. |
| Generation |
The number of times Unity has used the same Index for different objects. |
Callbacks
This section is visible only if you set Callback Source to a value other than Off.
| Property |
Description |
| Joint Threshold |
How many times a joint callback was dispatched to a valid receiver. |
Other properties
| Property |
Description |
| Constraint Force |
The current force the constraint applies, as a vector in newtons. |
| Constraint Torque |
The current torque the constraint applies, in newton-meters. |
Additional resources
Physics Constraint Distance component reference
Physics Constraint Hinge component reference