Module: MJSite

class MJSite : public MJObject<mjsSite>

#include <MJSite.h>

Represents a MuJoCo site, which is a reference point attached to a body.

The MJSite class provides functionality to manage a ‘site’ in MuJoCo. A ‘site’ represents a point in MuJoCo where one may query dynamic information (such as position, orientation, velocity…) and apply forces and torques.

Public Functions

MJSite(mjsSite *site, MJBody &body)

Constructs an MJSite object with a given MuJoCo site object and the body where it’s attached.

Parameters:

• site – Pointer to the MuJoCo site.

• body – Reference to the body the site is attached to.

MJSite(const MJSite&) = delete

MJSite(MJSite&&) = delete

MJSite &operator=(const MJSite&) = delete

MJSite &operator=(MJSite&&) = delete

inline MJBody &getBody()

Retrieves the body the site is attached to.

Returns:

A reference to the attached MJBody object.

void setPositionRelativeToBody(const Eigen::Vector3d &position)

Sets the position of the site relative to the body it’s attached to.

Parameters:

position – The 3D position vector relative to the body, in the body reference frame.

void setAttitudeRelativeToBody(const Eigen::MRPd &attitude)

Sets the attitude (orientation) of the site relative to the body it’s attached to.

Parameters:

attitude – The orientation represented as Modified Rodrigues Parameters (MRP) from the body reference frame.

void writeFwdKinematicsMessage(mjModel *model, mjData *data, uint64_t CurrentSimNanos)

Writes the frame state message (stateOutMsg) based on the state of the site.

Sets the position, velocity, orientation, and angular rate of the site in the inertial frame, as parsed from the given MuJoCo model and data.

Parameters:

• model – Pointer to the MuJoCo model.

• data – Pointer to the MuJoCo simulation data.

• CurrentSimNanos – The current simulation time in nanoseconds.

Public Members

Message<SCStatesMsgPayload> stateOutMsg

Message to output site frame state.

Protected Attributes

MJBody &body

Reference to the body to which the site is attached.