# Unigine::JointSuspension Class

This class is used to create a suspension joint. The bodies that represent both a frame and a wheel must be rigid bodies.

### Example#

The following code illustrates connection of two rigid bodies (frame and wheel) using a suspension joint.

Source code (UnigineScript)
``````include <UniginePhysics.h>

/* .. */

JointSuspensionPtr joint = JointSuspension::create(frame, wheel);

// setting joint anchor coordinates
joint->setWorldAnchor(wheel->getObject()->getWorldTransform() * Vec3(0.0f));

// setting joint axes coordinates
joint->setWorldAxis0(vec3(0.0f,0.0f,1.0f));
joint->setWorldAxis1(vec3(0.0f,1.0f,0.0f));

// setting linear damping and spring rigidity
joint->setLinearDamping(2.0f);
joint->setLinearSpring(200.0f);

// setting lower and upper suspension ride limits [-0.5; 0.0]
joint->setLinearLimitFrom(-0.5f);
joint->setLinearLimitTo(0.0f);

// setting target suspension height
joint->setLinearDistance(0.5f);

// setting maximum angular velocity and torque
joint->setAngularVelocity(-20.0f);
joint->setAngularTorque(10.0f);

// setting common joint constraint parameters
joint->setLinearRestitution(0.2f);
joint->setAngularRestitution(0.2f);
joint->setLinearSoftness(0.2f);
joint->setAngularSoftness(0.2f);

// setting number of iterations
joint->setNumIterations(8);``````

## static JointSuspensionPtr create ( )

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

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

Constructor. Creates a suspension joint connecting two given bodies. An anchor is placed between centers of mass of the bodies.

### Arguments

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

## static JointSuspensionPtr create ( const Ptr<Body> & body0, const Ptr<Body> & body1, const Math::Vec3 & anchor, const Math::vec3 & axis0, const Math::vec3 & axis1 )

Constructor. Creates a suspension joint connecting two given bodies with specified suspension and spindle axis coordinates and an anchor placed at specified coordinates.

### Arguments

• const Ptr<Body> & body0 - Frame to be connected with the joint.
• const Ptr<Body> & body1 - Wheel to be connected with the joint.
• const Math::Vec3 & anchor - Anchor coordinates.
• const Math::vec3 & axis0 - Suspension axis coordinates.
• const Math::vec3 & axis1 - Wheel spindle axis coordinates.

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

Casts a JointWheel out of the Joint instance.

### Arguments

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

JointSuspension.

## voidsetAngularDamping( float damping )

Sets an angular damping of the joint (wheel rotation damping).

### Arguments

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

## floatgetAngularDamping( )

Returns the angular damping of the joint (wheel rotation damping).

Angular damping.

## voidsetAngularTorque( float torque )

Sets a maximum torque of the attached angular motor.

### Arguments

• float torque - Maximum torque. If a negative value is provided, 0 will be used instead.

## floatgetAngularTorque( )

Returns the maximum torque of the attached angular motor.

Maximum torque.

## voidsetAngularVelocity( float velocity )

Sets a maximum velocity of wheel rotation.

### Arguments

• float velocity - Velocity in radians per second.

## floatgetAngularVelocity( )

Returns the target velocity of wheel rotation.

### Return value

Target velocity in radians per second.

## voidsetAxis00( const Math::vec3 & axis00 )

Sets coordinates of suspension axis, along which a wheel moves vertically. This is a shock absorber.

### Arguments

• const Math::vec3 & axis00 - Suspension axis.

## Math::vec3getAxis00( )

Returns suspension axis coordinates.

Suspension axis.

## voidsetAxis10( const Math::vec3 & axis10 )

Sets a wheel spindle axis in coordinates of the frame (body 0): an axis around which a wheel rotates when moving forward (or backward).

### Arguments

• const Math::vec3 & axis10 - Wheel spindle axis in coordinates of the frame (body 0).

## Math::vec3getAxis10( )

Returns the wheel spindle axis in coordinates of the frame (body 0).

### Return value

Wheel spindle axis in coordinates of the frame (body 0).

## voidsetAxis11( const Math::vec3 & axis11 )

Sets a wheel spindle axis in coordinates of the wheel (body 1): an axis around which a wheel rotates when steering.

### Arguments

• const Math::vec3 & axis11 - Wheel spindle axis in coordinates of the wheel (body 1).

## Math::vec3getAxis11( )

Returns the wheel spindle in coordinates of the wheel (body 1).

### Return value

Wheel spindle axis in coordinates of the wheel (body 1).

## floatgetCurrentAngularVelocity( )

Returns the current velocity of wheel rotation.

### Return value

Current velocity in radians per second.

## floatgetCurrentLinearDistance( )

Returns the current suspension compression.

### Return value

Current suspension height in units.

## voidsetLinearDamping( float damping )

Sets a linear damping of the suspension.

### Arguments

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

## floatgetLinearDamping( )

Returns the linear damping of the suspension.

Linear damping.

## voidsetLinearDistance( float distance )

Sets a target height of the suspension.

### Arguments

• float distance - Height in units.

## floatgetLinearDistance( )

Returns the target height of the suspension.

### Return value

Target height in units.

## voidsetLinearLimitFrom( float from )

Sets a low limit of the suspension ride.

### Arguments

• float from - Limit in units.

## floatgetLinearLimitFrom( )

Returns the low limit of the suspension ride.

### Return value

Low limit in units.

## voidsetLinearLimitTo( float to )

Sets a high limit of the suspension ride.

### Arguments

• float to - Limit in units.

## floatgetLinearLimitTo( )

Returns the high limit of the suspension ride.

### Return value

High limit in units.

## voidsetLinearSpring( float spring )

Sets a rigidity coefficient of the suspension.

### Arguments

• float spring - Rigidity coefficient. If a negative value is provided, 0 will be used instead.

## floatgetLinearSpring( )

Returns the rigidity coefficient of the suspension.

### Return value

Rigidity coefficient.

## voidsetWorldAxis0( const Math::vec3 & axis0 )

Sets suspension axis in the world coordinates.

### Arguments

• const Math::vec3 & axis0 - Suspension axis in the world coordinates.

## Math::vec3getWorldAxis0( )

Returns the suspension axis in the world coordinates.

### Return value

Suspension axis in the world coordinates.

## voidsetWorldAxis1( const Math::vec3 & axis1 )

Sets a wheel spindle axis in the world coordinates.

### Arguments

• const Math::vec3 & axis1 - Wheel spindle axis in the world coordinates.

## Math::vec3getWorldAxis1( )

Returns the wheel spindle axis in the world coordinates.

### Return value

Wheel spindle axis in the world coordinates.
Last update: 2018-12-27