# Unigine::BodyParticles Class

Header: | #include <UniginePhysics.h> |

Inherits: | Body |

BodyParticles is a base class for BodyCloth and BodyRope classes. It uses a mass-spring simulation model, i.e. particles that are connected by inner joints. The particles are of sphere shape and characterized by a position, mass and velocity. The total mass of the whole cloth is distributed among them. Particles can be acted upon by a force or an impulse. The inner joints can be stretched (linear and angular separately), or linear joints can also be scaled, which provides the same stretching effect. When stretched to the specified distance, joins are torn (the distance is set separately for linear and angular joints).

### See Also*#*

- The Creating and Attaching a Cloth usage example demonstrating how to set rope parameters

## BodyParticles Class

### Members

## void setAngularRestitution( float restitution )

Sets the restitution of the body's inner joints, when triangles formed by particles are folded angularly relative to each other.### Arguments

*float***restitution**- Joints angular restitution. Provided value is saturated in range**[0;1.0]**.

## float getAngularRestitution( )

Returns the current restitution of the body's inner joints, when triangles formed by particles are folded angularly relative to each other.### Return value

Joints angular restitution.## void setAngularThreshold( float threshold )

Sets the threshold for angular folding of particles triangles connected by inner joints. When passing this threshold, the joints tear up.### Arguments

*float***threshold**- Joints angular folding threshold. If a negative value is provided,**0**will be used instead.

## float getAngularThreshold( )

Returns the current threshold for angular folding of particles triangles connected by inner joints. When passing this threshold, the joints tear up.### Return value

Joints angular folding threshold.## Ptr<BodyParticles> getBodyParticles( )

## void setCollision( int collision )

Sets a value indicating if collision with a body is enabled or not.### Arguments

*int***collision**- Positive value to enable collision,**0**to disable it.

## int getCollision( )

Returns a value indicating if collision with a body is enabled or not.### Return value

Positive value if collision is enabled,**0**if disabled.

## void setCollisionMask( int mask )

Sets a collision bit mask for the body. Two objects collide, if they both have matching masks.### Arguments

*int***mask**- Integer, each bit of which is a mask.

## int getCollisionMask( )

Returns a collision bit mask for the body. Two objects collide, if they both have matching masks.### Return value

Integer, each bit of which is a mask.## void setDistance( float distance )

Sets the distance of body simulation.### Arguments

*float***distance**- Distance of simulation. If a negative value is provided,**0**will be used instead.

## float getDistance( )

Returns the current distance of body simulation.### Return value

Distance of simulation.## void setFriction( float friction )

Sets the friction of the body by its contact with other surfaces.### Arguments

*float***friction**- Body friction. If a negative value is provided,**0**will be used instead.

## float getFriction( )

Returns the current friction of the body by its contact with other surfaces.### Return value

Body friction.## void setLinearDamping( float damping )

Sets a value indicating how much the linear velocity of the particles decreases over time.### Arguments

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

## float getLinearDamping( )

Returns a value indicating how much the linear velocity of the particles decreases over time.### Return value

Linear damping value.## void setLinearRestitution( float restitution )

Sets the restitution of the body's inner joints by linear stretching.### Arguments

*float***restitution**- Joints linear restitution. Provided value is saturated in range**[0;1.0]**.

## float getLinearRestitution( )

Returns the current restitution of the body's inner joints by linear stretching.### Return value

Joints linear restitution.## void setLinearStretch( float stretch )

Sets the scale for the length of linear joints (relative the source mesh topology).### Arguments

*float***stretch**- Stretch scale for linear joints. If a negative value is provided,**0**will be used instead.

## float getLinearStretch( )

Returns the current scale for the length of linear joints (relative the source mesh topology).### Return value

Stretch scale for linear joints.## void setLinearThreshold( float threshold )

Sets the threshold for linear stretching of the body's inner joints. When passing this threshold, the joints tear up.### Arguments

*float***threshold**- Linear stretching threshold. If a negative value is provided,**0**will be used instead.

## float getLinearThreshold( )

Returns the current linear stretching of the body's inner joints. When passing this threshold, the joints tear up.### Return value

Joints linear stretching threshold.## void setMass( float mass )

Sets a mass of the body.### Arguments

*float***mass**- Mass of the body. If a negative value is provided,**0**will be used instead.

## float getMass( )

Returns the current mass of the body.### Return value

Mass of the body.## void setNumIterations( int iterations )

Sets the number of iterations used to solve inner joints between the particles. Note that if this value is too low, the precision of calculations will suffer.### Arguments

*int***iterations**- Number of iterations. If a non-positive value is provided,**1**will be used instead.

## int getNumIterations( )

Returns the current number of iterations used to solve inner joints between particles.### Return value

Number of iterations.## int getNumParticles( )

Returns the total number of particles that constitute the body.### Return value

The number of particles.## void setParticleMass( int num, float mass )

Sets the mass for the specified particle.### Arguments

*int***num**- Particle number.*float***mass**- Particle mass.

## float getParticleMass( int num )

Returns the current mass of the specified particle.### Arguments

*int***num**- Particle number.

### Return value

Particle mass.## void setParticlePosition( int num, const Math::Vec3 & position )

Sets the position of the specified body's particle.### Arguments

*int***num**- Particle number.*const Math::Vec3 &***position**- Particle position in world coordinates.

## Math::Vec3 getParticlePosition( int num )

Returns the current position of the specified particle.### Arguments

*int***num**- Particle number.

### Return value

Particle position in world coordinates.## void setParticleVelocity( int num, const Math::vec3 & velocity )

Sets the velocity of the specified particle.### Arguments

*int***num**- Particle number.*const Math::vec3 &***velocity**- Particle velocity.

## Math::vec3 getParticleVelocity( int num )

Returns the current velocity of the specified particle.### Arguments

*int***num**- Particle number.

### Return value

Particle velocity.## void setRadius( float radius )

Sets the radius of the particles forming the body and represented as sphere shapes.### Arguments

*float***radius**- Radius of the sphere-shaped particles.

## float getRadius( )

Returns the current radius of the particles forming the body and represented as sphere shapes.### Return value

Radius of the sphere-shaped particles.## void setRestitution( float restitution )

Sets the restitution of the body by bouncing.### Arguments

*float***restitution**- Body restitution. Provided value is saturated in range**[0;1.0]**.

## float getRestitution( )

Returns the current restitution of the body by bouncing.### Return value

Body restitution.## void setRigidity( float rigidity )

Sets rigidity of the body's inner joints movement, i.e. how much interpolated linear and angular velocities of all joints affect velocities of each separate joint.### Arguments

*float***rigidity**- Rigidity of joints interaction. Provided value is saturated in range**[0;1.0]**:- By the value of
**0**, joints move independently. - By the value of
**1**, joints move uniformly, as interpolated velocity greatly changes velocities of each joint.

- By the value of

## float getRigidity( )

Returns the current rigidity of the body's inner joints movement, i.e. how much interpolated linear and angular velocities of all joints affect velocities of each separate joint.### Return value

Rigidity of joints movement:- By the value of
**0**, joints move independently. - By the value of
**1**, joints move uniformly, as interpolated velocity greatly changes velocities of each joint.

## void addParticleForce( int num, const Math::vec3 & force )

Applies a force to the given particle. Integrated forces are applied after calling the update.### Arguments

*int***num**- Particle number.*const Math::vec3 &***force**- Amount of force to apply.

## void addParticleImpulse( int num, const Math::vec3 & impulse )

Applies an impulse to the given particle. Impulses immediately affect particles velocities.### Arguments

*int***num**- Particle number.*const Math::vec3 &***impulse**- Amount of impulse to apply.

Last update:
2020-01-14

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