# PhysicsFixedJoint > A joint to constrain a pair of bodies together rigidly. This constraint provides springs to mimic soft-body simulation. The approximate solver cannot always hold many bodies together completely rigidly. ## Definition * **Type:** Struct * **Namespace:** [UnityEngine.LowLevelPhysics2D](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d.md) * **Assembly:** UnityEngine.Physics2DModule * **Implements:** [IEquatable\](https://learn.microsoft.com/dotnet/api/system.iequatable-1) ```csharp public readonly struct PhysicsFixedJoint : IEquatable ``` ## Constructors | Constructor | Description | | -------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [PhysicsFixedJoint(UnityEngine.LowLevelPhysics2D.PhysicsJoint)](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/ctor.md) | Create a [PhysicsFixedJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint.md) from the specified base joint. The provided joint must be a joint type of [PhysicsJoint.JointType.FixedJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint/jointtype/fixedjoint.md). | ## Properties | Property | Description | | ------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [angularDamping](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/angulardamping.md) | Angular damping, non-dimensional. Use 1 for critical damping. | | [angularFrequency](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/angularfrequency.md) | Angular stiffness in cycles per second. Use zero for maximum stiffness. | | [bodyA](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/bodya.md) | The first body the joint constrains. | | [bodyB](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/bodyb.md) | The second body the joint constrains. | | [callbackTarget](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/callbacktarget.md) | Get/Set the Object that event callbacks for this joint will be sent to. Care should be taken with any Object assigned as a callback target that isn't a [Object](/engine/6000.3/script-reference/unityengine/object.md) as this assignment will not in itself keep the object alive and can be garbage collected. To avoid this, you should have at least a single reference to the object in your code. | | [collideConnected](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/collideconnected.md) | Whether the shapes on the pair of bodies can come into contact. | | [currentAngularSeparationError](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/currentangularseparationerror.md) | Get the current angular separation error for this joint, in degrees. This does not consider admissible movement. | | [currentConstraintForce](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/currentconstraintforce.md) | Get the current constraint force used by the joint, usually in newtons. | | [currentConstraintTorque](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/currentconstrainttorque.md) | Get the current constraint torque used by the joint, usually in newton-meters. | | [currentLinearSeparationError](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/currentlinearseparationerror.md) | Get the current linear separation error for this joint, usually in meters. This does not consider admissible movement. | | [drawScale](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/drawscale.md) | Controls the scaling of the joint drawing. | | [forceThreshold](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/forcethreshold.md) | The force threshold beyond which a joint event will be produced. | | [isOwned](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/isowned.md) | Get if the joint is owned. See [PhysicsJoint.SetOwner](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint/setowner.md). | | [isValid](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/isvalid.md) | Checks if the joint is valid. | | [jointType](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/jointtype.md) | Gets the joint type. See [PhysicsJoint.JointType](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint/jointtype.md). | | [linearDamping](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/lineardamping.md) | Linear damping, non-dimensional. Use 1 for critical damping. | | [linearFrequency](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/linearfrequency.md) | Linear stiffness in cycles per second. Use zero for maximum stiffness. | | [localAnchorA](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/localanchora.md) | The local anchor frame constraint relative to bodyA's origin. | | [localAnchorB](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/localanchorb.md) | The local anchor frame constraint relative to bodyB's origin. | | [ownerUserData](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/owneruserdata.md) | Get [PhysicsUserData](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsuserdata.md) that can be used for any purpose, typically by the owner only. | | [torqueThreshold](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/torquethreshold.md) | The torque threshold beyond which a joint event will be produced. | | [tuningDamping](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/tuningdamping.md) | Controls the joint stiffness damping, non-dimensional. Use 1 for critical damping. | | [tuningFrequency](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/tuningfrequency.md) | Controls the joint stiffness frequency, in cycles per second. | | [userData](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/userdata.md) | Get/Set [PhysicsUserData](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsuserdata.md) that can be used for any purpose. The physics system doesn't use this data, it is entirely for custom use. | | [world](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/world.md) | Get the world the body is attached to. | ## Methods | Method | Description | | ----------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [Destroy](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/destroy.md) | Destroy the joint. If the object is owned with [PhysicsJoint.SetOwner](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint/setowner.md) then you must provide the owner key it returned. Failing to do so will return a warning and the joint will not be destroyed. | | [Draw](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/draw.md) | Draw a PhysicsJoint that visually represents its current state in the world. This is only used in the Unity Editor or in a Development Player. | | [GetOwner](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/getowner.md) | Get the owner object associated with this joint as specified using [PhysicsJoint.SetOwner](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint/setowner.md). | | [SetOwner](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/setowner.md) | Set the (optional) owner object associated with this joint and return an owner key that must be specified when destroying the joint with [PhysicsJoint.Destroy](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint/destroy.md). The physics system provides access to all objects, including the ability to destroy them so this feature can be used to stop accidental destruction of objects that are owned by other objects. You can only set the owner once, multiple attempts will produce a warning. The lifetime of the specified owner object is not linked to this joint i.e. this joint will still be owned by the owner object, even if it is destroyed. It is also valid to not specify an owner object (NULL) to simply gain an owner key however it can be useful, if simply for debugging purposes and discovery, to know which object is the owner. | | [SetOwnerUserData](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/setowneruserdata.md) | Set [PhysicsUserData](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsuserdata.md) that can be used for any purpose, typically by the owner only. | | [WakeBodies](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/wakebodies.md) | Wake the pair of bodies the joint is constraining. | ## Static Methods | Method | Description | | --------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [Create](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/create.md) | Create a [PhysicsFixedJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint.md) in the specified world. | | [DestroyBatch](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/destroybatch.md) | Destroy a batch of joints. Owned joints will produce a warning and will not be destroyed (see [PhysicsJoint.SetOwner](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint/setowner.md)). Any invalid joints will be ignored. | ## Operators | Operator | Description | | ------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | [PhysicsJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/op-implicit.md) | Cast to the base [PhysicsJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint.md). | | [PhysicsFixedJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint/op-implicit.md) | Cast to a [PhysicsFixedJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsfixedjoint.md) from the base [PhysicsJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint.md). The provided joint must be a joint type of [PhysicsJoint.JointType.FixedJoint](/engine/6000.3/script-reference/unityengine/lowlevelphysics2d/physicsjoint/jointtype/fixedjoint.md). |