Constraints¶

RaiSim currently has two types of constraints:

Both constraints offer three stretch types: STRETCH_RESISTANT_ONLY, COMPRESSION_RESISTANT_ONLY, BOTH. The first two are unilateral constraints (i.e., acting only in one direction) and BOTH is a bilateral constraint (i.e., acting in both directions). The stretch types are explained in StiffLengthConstraint.

You can find a short example in examples/src/server/newtonsCradle.cpp. This code simulates the following dynamics

API¶

LengthConstraint¶

class LengthConstraint : public raisim::Constraints¶

Subclassed by raisim::CompliantLengthConstraint, raisim::CustomLengthConstraint, raisim::StiffLengthConstraint

Public Functions

void update(contact::ContactProblems &contact_problems)¶: update internal variables (called by World::integrate1())

double getLength() const¶

Returns: the length of the wire

inline double getVisualizationWidth()¶

get wire width for visualization

Returns: width

inline void setVisualizationWidth(double width)¶

set visualization width

Parameters: width – width

double getDistance() const¶

Returns: the distance between the two mounting points

const Vec<3> &getP1() const¶

Returns: the first attachment point in the World frame

const Vec<3> &getP2() const¶

Returns: the second attachment point in the World frame

Object *getBody1() const¶

Returns: the first object to which the wire is attached

Object *getBody2() const¶

Returns: the second object to which the wire is attached

const Vec<3> &getNorm() const¶

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

size_t getLocalIdx1() const¶

Returns: the local index of object1

size_t getLocalIdx2() const¶

Returns: the local index of object2

double getStretch() const¶

Returns: the stretch length (i.e., constraint violation)

inline void setName(const std::string &name)¶

set name of the wire

Parameters: name – the constraint’s name

inline const std::string &getName() const¶

get name of the wire

Returns: the wire name

inline void setStretchType(StretchType type)¶

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

Parameters: type – the wire stretch type. Available types: STRETCH_RESISTANT_ONLY, COMPRESSION_RESISTANT_ONLY, BOTH

inline StretchType getStretchType() const¶

get the constraint’s stretch type

Returns: the wire stretch type

inline WireType getWireType() const¶

get wire type

Returns: wire type

const Vec<3> &getOb1MountPos() const¶

get pos on ob1 where the wire is attached

Returns: mount position 1

const Vec<3> &getOb2MountPos() const¶

get pos on ob2 where the wire is attached

Returns: mount position 2