ModelingInputs a user-defined marker element.

## Use

<Reference_Marker
id                  = "30102040"
label               = "Joint 3-Marker I"
body_id             = "30102"
body_type           = "RigidBody"
usrsub_param_string = "USER(1,-0.5, 0.3, 0., 1.57079633, 1.57079633, -1.57079633)"
usrsub_dll_name     = "NULL"
/>

## Format

Fortran Calling Syntax
SUBROUTINE MARKER_READ (ID, PAR, NPAR, ERRFLG)
C/C++ Calling Syntax
void STDCALL MARKER_READ (int *id, double *par, int *npar, int *errflg)
Python Calling Syntax
def MARKER_READ(id, par, npar):
return function errflg = MARKER_READ(id, par, npar)
MATLAB Calling Syntax
function errflg = MARKER_READ(id, par, npar)

## Attributes

ID
[integer]
The marker element identifier.
PAR
[double precision]
An array that contains the constant arguments from the list provided in the user-defined statement.
NPAR
[integer]
The number of entries in the PAR array.
ERRFLAG
[integer]
The error flag.

## Example

def MARKER_READ(id, par, npar):
eflg = 0
errflg = 0
r = 3 *[0.0]
angle = 6*[0.0]
angle_type = int(par[0])
r[0] = par[1]
r[1] = par[2]
r[2] = par[3]
if angle_type==0: # DCMTX
angle[0] = par[4]
angle[1] = par[5]
angle[2] = par[6]
angle[3] = par[7]
angle[4] = par[8]
angle[5] = par[9]
elif (angle_type == 1) | (angle_type == 2):# Euler angles (313 or YPR)
angle[0] = par[4]
angle[1] = par[5]
angle[2] = par[6]
elif angle_type == 3: # Euler parameters
angle[0] = par[4]
angle[1] = par[5]
angle[2] = par[6]
angle[3] = par[7]
else:
errflg = 1;
return errflg
eflg = py_put_marker(id, r, angle_type, angle)
return errflg