# Unigine::JointPath Class

A path joint is used with BodyPath: it attaches an arbitrary BodyRigid to move along its path.

Notice
The path is a spline along which an object can be moved.

• A set of samples located in the data/samples/ directory, namely:
1. physics/train_00.cpp
2. joints/path_00.cpp

### Example#

The following code illustrates connection of a rigid body (b0) and a path body (b1) using a path joint.

Source code (C++)
``````include <UniginePhysics.h>

/* .. */

JointPathPtr joint = JointPath::create(b0, b1);

// setting linear damping, velocity and force limits
joint->setLinearDamping(200.0f);
joint->setLinearVelocity(-100.0f);
joint->setLinearForce(1000.0f);

// setting body orientation regarding the path
joint->setRotation0(rotateZ(90.0f));

// setting number of iterations
joint->setNumIterations(4);``````

## static JointPathPtr create ( )

Constructor. Creates a path joint with an anchor at the origin of the world coordinates.

## static JointPathPtr create ( const Ptr<Body> & body0, const Ptr<Body> & body1 )

Constructor. Creates a path joint connecting two given bodies. An anchor is placed in the center of the rigid body attached the path body.

### Arguments

• const Ptr<Body> & body0 - BodyRigid to be connected with the joint.
• const Ptr<Body> & body1 - BodyPath to be connected with the joint.

## static JointPathPtr create ( const Ptr<Body> & body0, const Ptr<Body> & body1, const Math::Vec3 & anchor )

Constructor. Creates a path joint connecting two given bodies with an anchor placed at specified coordinates.

### Arguments

• const Ptr<Body> & body0 - BodyRigid to be connected with the joint.
• const Ptr<Body> & body1 - BodyPath to be connected with the joint.
• const Math::Vec3 & anchor - Anchor coordinates.

## Ptr<JointPath>cast( const Ptr<Joint> & joint )

Casts a JointPath out of the Joint instance.

### Arguments

• const Ptr<Joint> & joint - Joint instance.

JointPath.

## floatgetCurrentLinearVelocity( )

Returns the current linear velocity of the attached motor.

### Return value

Current linear velocity in units per second.

## voidsetLinearDamping( float damping )

Sets damping factor of linear velocities of bodies connected by the joint.

### Arguments

• float damping - Linear damping to be set. If a negative value is provided, 0 will be used instead.

## floatgetLinearDamping( )

Returns the current damping factor for linear velocities of bodies connected by the joint.

Linear damping.

## voidsetLinearForce( float force )

Sets a maximum force of the attached motor. 0 means that the motor is not attached.

### Arguments

• float force - Maximum force to be set. If a negative value is provided, 0 will be used instead. 0 detaches the motor.

## floatgetLinearForce( )

Returns the maximum force of the attached motor.

Maximum force.

## voidsetLinearVelocity( float velocity )

Sets a target linear velocity of the attached motor.

### Arguments

• float velocity - Target velocity in units per second.

## floatgetLinearVelocity( )

Returns the current linear velocity of the attached motor.

### Return value

Target velocity in units per second.

## voidsetRotation0( const Math::mat3 & rotation0 )

Sets a rotation matrix of the anchor point in a system of coordinates of the connected rigid body.

### Arguments

• const Math::mat3 & rotation0 - Rotation matrix in the body-space coordinates.

## voidsetWorldRotation( const Math::mat3 & rotation )

Sets a rotation matrix of the anchor point in the world coordinates.

### Arguments

• const Math::mat3 & rotation - Rotation matrix in the world-space coordinates.

## Math::mat3getWorldRotation( )

Returns rotation matrix of the anchor point in the world coordinates.

### Return value

Rotation matrix in the world-space coordinates.
Last update: 2018-12-27