# Class: WheelJoint A wheel joint. This joint provides two degrees of freedom: translation along an axis fixed in bodyA and rotation in the plane. In other words, it is a point to line constraint with a rotational motor and a linear spring/damper. This joint is designed for vehicle suspensions. ## Extends - [`Joint`](/api/classes/Joint) ## Constructors ### new WheelJoint() > **new WheelJoint**(`def`): [`WheelJoint`](/api/classes/WheelJoint) #### Parameters • **def**: [`WheelJointDef`](/api/interfaces/WheelJointDef) #### Returns [`WheelJoint`](/api/classes/WheelJoint) #### Overrides [`Joint`](/api/classes/Joint).[`constructor`](/api/classes/Joint#constructors) ### new WheelJoint() > **new WheelJoint**(`def`, `bodyA`, `bodyB`, `anchor`?, `axis`?): [`WheelJoint`](/api/classes/WheelJoint) #### Parameters • **def**: [`WheelJointOpt`](/api/interfaces/WheelJointOpt) • **bodyA**: [`Body`](/api/classes/Body) • **bodyB**: [`Body`](/api/classes/Body) • **anchor?**: [`Vec2Value`](/api/interfaces/Vec2Value) • **axis?**: [`Vec2Value`](/api/interfaces/Vec2Value) #### Returns [`WheelJoint`](/api/classes/WheelJoint) #### Overrides [`Joint`](/api/classes/Joint).[`constructor`](/api/classes/Joint#constructors) ## Properties ### style > **style**: [`Style`](/api/interfaces/Style) = `{}` Styling for dev-tools. #### Inherited from [`Joint`](/api/classes/Joint).[`style`](/api/classes/Joint#style) *** ### TYPE > `static` **TYPE**: `"wheel-joint"` ## Methods ### enableMotor() > **enableMotor**(`flag`): `void` Enable/disable the joint motor. #### Parameters • **flag**: `boolean` #### Returns `void` *** ### getAnchorA() > **getAnchorA**(): [`Vec2`](/api/classes/Vec2) Get the anchor point on bodyA in world coordinates. #### Returns [`Vec2`](/api/classes/Vec2) #### Overrides [`Joint`](/api/classes/Joint).[`getAnchorA`](/api/classes/Joint#getanchora) *** ### getAnchorB() > **getAnchorB**(): [`Vec2`](/api/classes/Vec2) Get the anchor point on bodyB in world coordinates. #### Returns [`Vec2`](/api/classes/Vec2) #### Overrides [`Joint`](/api/classes/Joint).[`getAnchorB`](/api/classes/Joint#getanchorb) *** ### getBodyA() > **getBodyA**(): [`Body`](/api/classes/Body) Get the first body attached to this joint. #### Returns [`Body`](/api/classes/Body) #### Inherited from [`Joint`](/api/classes/Joint).[`getBodyA`](/api/classes/Joint#getbodya) *** ### getBodyB() > **getBodyB**(): [`Body`](/api/classes/Body) Get the second body attached to this joint. #### Returns [`Body`](/api/classes/Body) #### Inherited from [`Joint`](/api/classes/Joint).[`getBodyB`](/api/classes/Joint#getbodyb) *** ### getCollideConnected() > **getCollideConnected**(): `boolean` Get collide connected. Note: modifying the collide connect flag won't work correctly because the flag is only checked when fixture AABBs begin to overlap. #### Returns `boolean` #### Inherited from [`Joint`](/api/classes/Joint).[`getCollideConnected`](/api/classes/Joint#getcollideconnected) *** ### getJointSpeed() > **getJointSpeed**(): `number` Get the current joint translation speed, usually in meters per second. #### Returns `number` *** ### getJointTranslation() > **getJointTranslation**(): `number` Get the current joint translation, usually in meters. #### Returns `number` *** ### getLocalAnchorA() > **getLocalAnchorA**(): [`Vec2`](/api/classes/Vec2) The local anchor point relative to bodyA's origin. #### Returns [`Vec2`](/api/classes/Vec2) *** ### getLocalAnchorB() > **getLocalAnchorB**(): [`Vec2`](/api/classes/Vec2) The local anchor point relative to bodyB's origin. #### Returns [`Vec2`](/api/classes/Vec2) *** ### getLocalAxisA() > **getLocalAxisA**(): [`Vec2`](/api/classes/Vec2) The local joint axis relative to bodyA. #### Returns [`Vec2`](/api/classes/Vec2) *** ### getMaxMotorTorque() > **getMaxMotorTorque**(): `number` #### Returns `number` *** ### getMotorSpeed() > **getMotorSpeed**(): `number` Get the motor speed, usually in radians per second. #### Returns `number` *** ### getMotorTorque() > **getMotorTorque**(`inv_dt`): `number` Get the current motor torque given the inverse time step, usually in N-m. #### Parameters • **inv\_dt**: `number` #### Returns `number` *** ### getNext() > **getNext**(): [`Joint`](/api/classes/Joint) Get the next joint the world joint list. #### Returns [`Joint`](/api/classes/Joint) #### Inherited from [`Joint`](/api/classes/Joint).[`getNext`](/api/classes/Joint#getnext) *** ### getReactionForce() > **getReactionForce**(`inv_dt`): [`Vec2`](/api/classes/Vec2) Get the reaction force on bodyB at the joint anchor in Newtons. #### Parameters • **inv\_dt**: `number` #### Returns [`Vec2`](/api/classes/Vec2) #### Overrides [`Joint`](/api/classes/Joint).[`getReactionForce`](/api/classes/Joint#getreactionforce) *** ### getReactionTorque() > **getReactionTorque**(`inv_dt`): `number` Get the reaction torque on bodyB in N*m. #### Parameters • **inv\_dt**: `number` #### Returns `number` #### Overrides [`Joint`](/api/classes/Joint).[`getReactionTorque`](/api/classes/Joint#getreactiontorque) *** ### getSpringDampingRatio() > **getSpringDampingRatio**(): `number` #### Returns `number` *** ### getSpringFrequencyHz() > **getSpringFrequencyHz**(): `number` #### Returns `number` *** ### getType() > **getType**(): `string` Get the type of the concrete joint. #### Returns `string` #### Inherited from [`Joint`](/api/classes/Joint).[`getType`](/api/classes/Joint#gettype) *** ### getUserData() > **getUserData**(): `unknown` #### Returns `unknown` #### Inherited from [`Joint`](/api/classes/Joint).[`getUserData`](/api/classes/Joint#getuserdata) *** ### initVelocityConstraints() > **initVelocityConstraints**(`step`): `void` #### Parameters • **step**: [`TimeStep`](/api/classes/TimeStep) #### Returns `void` #### Overrides [`Joint`](/api/classes/Joint).[`initVelocityConstraints`](/api/classes/Joint#initvelocityconstraints) *** ### isActive() > **isActive**(): `boolean` Short-cut function to determine if either body is inactive. #### Returns `boolean` #### Inherited from [`Joint`](/api/classes/Joint).[`isActive`](/api/classes/Joint#isactive) *** ### isMotorEnabled() > **isMotorEnabled**(): `boolean` Is the joint motor enabled? #### Returns `boolean` *** ### setMaxMotorTorque() > **setMaxMotorTorque**(`torque`): `void` Set/Get the maximum motor force, usually in N-m. #### Parameters • **torque**: `number` #### Returns `void` *** ### setMotorSpeed() > **setMotorSpeed**(`speed`): `void` Set the motor speed, usually in radians per second. #### Parameters • **speed**: `number` #### Returns `void` *** ### setSpringDampingRatio() > **setSpringDampingRatio**(`ratio`): `void` Set/Get the spring damping ratio #### Parameters • **ratio**: `number` #### Returns `void` *** ### setSpringFrequencyHz() > **setSpringFrequencyHz**(`hz`): `void` Set/Get the spring frequency in hertz. Setting the frequency to zero disables the spring. #### Parameters • **hz**: `number` #### Returns `void` *** ### setUserData() > **setUserData**(`data`): `void` #### Parameters • **data**: `unknown` #### Returns `void` #### Inherited from [`Joint`](/api/classes/Joint).[`setUserData`](/api/classes/Joint#setuserdata) *** ### shiftOrigin() > **shiftOrigin**(`newOrigin`): `void` Shift the origin for any points stored in world coordinates. #### Parameters • **newOrigin**: [`Vec2Value`](/api/interfaces/Vec2Value) #### Returns `void` #### Inherited from [`Joint`](/api/classes/Joint).[`shiftOrigin`](/api/classes/Joint#shiftorigin) *** ### solvePositionConstraints() > **solvePositionConstraints**(`step`): `boolean` This returns true if the position errors are within tolerance. #### Parameters • **step**: [`TimeStep`](/api/classes/TimeStep) #### Returns `boolean` #### Overrides [`Joint`](/api/classes/Joint).[`solvePositionConstraints`](/api/classes/Joint#solvepositionconstraints) *** ### solveVelocityConstraints() > **solveVelocityConstraints**(`step`): `void` #### Parameters • **step**: [`TimeStep`](/api/classes/TimeStep) #### Returns `void` #### Overrides [`Joint`](/api/classes/Joint).[`solveVelocityConstraints`](/api/classes/Joint#solvevelocityconstraints)