raisim::LengthConstraint

abstract class · #include <raisim/constraints/LengthConstraint.hpp>

Inherits: raisim::Constraints
Derived by: raisim::CompliantLengthConstraint, raisim::CustomLengthConstraint, raisim::StiffLengthConstraint

Base class of the legacy distance constraints ("wires") between two points on two objects. Create them with World::addStiffWire(), World::addCompliantWire() or World::addCustomWire(); the world owns them. Internally each wire is backed by a two-site spatial Tendon.

Public types

WireType

enum class WireType : int

Concrete wire model.

Enumerator	Value	Description
STIFF	0	StiffLengthConstraint: hard length limit.
COMPLIANT		CompliantLengthConstraint: spring with stiffness.
CUSTOM		CustomLengthConstraint: user-specified tension.

StretchType

enum class StretchType : int

Which length deviation the wire resists.

Enumerator	Value	Description
STRETCH_RESISTANT_ONLY	0	Resists only distances longer than the length (like a rope). Default for stiff and compliant wires created by World.
COMPRESSION_RESISTANT_ONLY		Resists only distances shorter than the length.
BOTH		Resists both.

Constructors & destructor

LengthConstraint

LengthConstraint(
    Object *obj1,
    size_t localIdx1,
    Vec<3> pos1_b,
    Object *obj2,
    size_t localIdx2,
    Vec<3> pos2_b,
    double length)

Use the World::add*Wire() functions instead of constructing wires directly.

Parameters

Parameter	Description
obj1 (in)	first object (non-null)
localIdx1 (in)	local body index on obj1
pos1_b (in)	mount position in obj1's body frame
obj2 (in)	second object (non-null)
localIdx2 (in)	local body index on obj2
pos2_b (in)	mount position in obj2's body frame
length (in)	rest length in meters (finite, nonnegative). Throws std::invalid_argument otherwise

~LengthConstraint

virtual ~LengthConstraint()

Public member functions

getTendon

Tendon *getTendon() const

Compatibility view of a World-owned tendon; null before registration.

Returns the backing tendon (owned by World) or nullptr

update

void update(contact::ContactProblems &contact_problems)

update internal variables (called by World::integrate1())

Parameters

Parameter	Description
contact_problems (in, out)	contact problems of the world

getLength

double getLength() const

Returns the configured nominal (rest) length of the wire in meters, not the current separation (see getDistance())

getVisualizationWidth

double getVisualizationWidth()

get wire width for visualization

Returns width in meters

setVisualizationWidth

void setVisualizationWidth(double width)

set visualization width. A width of zero hides the wire.

Parameters

Parameter	Description
width (in)	width in meters. Must be finite and nonnegative (throws std::invalid_argument otherwise)

getDistance

double getDistance() const

Returns the distance between the two mounting points (m) at the last update

getP1

const Vec<3> &getP1() const

Returns the first attachment point in the World frame

getP2

const Vec<3> &getP2() const

Returns the second attachment point in the World frame

getBody1

Object *getBody1() const

Returns the first object to which the wire is attached

getBody2

Object *getBody2() const

Returns the second object to which the wire is attached

getNorm

const Vec<3> &getNorm() const

Returns the direction of the normal (i.e., p2-p1 normalized)

getLocalIdx1

size_t getLocalIdx1() const

Returns the local index of object1

getLocalIdx2

size_t getLocalIdx2() const

Returns the local index of object2

getStretch

double getStretch() const

Returns the stretch length, getDistance() - getLength() (m), at the last update

setName

void setName(const std::string &name)

set name of the wire

Parameters

Parameter	Description
name (in)	the constraint's name

getName

const std::string &getName() const

get name of the wire

Returns the wire name

setStretchType

void setStretchType(StretchType type)

set stretch type of the wire Check http://raisim.com/sections/StiffLengthConstraint.html

Parameters

Parameter	Description
type (in)	the wire stretch type. Available types: STRETCH_RESISTANT_ONLY, COMPRESSION_RESISTANT_ONLY, BOTH

getStretchType

StretchType getStretchType() const

get the constraint's stretch type

Returns the wire stretch type

getWireType

WireType getWireType() const

get wire type

Returns wire type

getOb1MountPos

const Vec<3> &getOb1MountPos() const

get pos on ob1 where the wire is attached

Returns mount position 1 in body1's frame

getOb2MountPos

const Vec<3> &getOb2MountPos() const

get pos on ob2 where the wire is attached

Returns mount position 2 in body2's frame

Public attributes

isActive

bool isActive

True when the constraint is active in the solver.

Inherited members

From raisim::Constraints: getColor, lock, lockMutex, setColor, try_lock, unlock, unlockMutex