Marker

Class Name

Marker

Description

The Newtonian reference frame (Ground) is considered to be a special case of a rigid PART.

Attribute Summary

Name	Property	Modifiable by command?	Designable?
id	Int ()
label	Str ()
part	Reference (Part)		Yes
point_mass	Reference (PointMass)		Yes
flex_body	Reference (FlexBody)		Yes
body	Reference (Body) # Alias	Yes	Yes
qp	Location (Point(), required=True)	Yes	Yes
zp	Location ()	Yes	Yes
xp	Location ()	Yes	Yes
xv	Location()		Yes
zv	Location()		Yes
reuler	Angles ()	Yes	Yes
floating	Bool ()
rm	Reference ("Marker")
node	Int ()
usexp	Bool ()
usexv	Bool ()
function	Function ("MARKER_READ()")
routine	Routine ()

Usage

#1: Defined completely in the input file 
Marker (body=objBody, optional_attributes)

#2: Defined in a compiled user-written subroutine
Marker (body=objBody, function=userString, routine=string, optional_attributes)

#3: Defined in a Python script
Marker (body=objBody, function=userString, routine=functionPointer, optional_attributes)

Attributes

Attributes Defined Completely in the Input File

body: Reference to an existing Part, PointMass or FlexBody object; Specifies an already existing PART, POINT_MASS or FLEX_BODY object to which the Marker belongs.; The body attribute is mandatory
qp: A Location object or a list of 3 doubles; Specifies the coordinates of the origin of the Marker in the RM Marker coordinate system.; The qp attribute is optional. When not specified, it is assumed to be coincident with the global origin, i.e. (0, 0, 0).
zp: A Location object or a list of 3 doubles; Specifies the coordinates of a point on the z-axis of the Marker in the RM Marker coordinate system.; The zp attribute is optional. When not specified, the point is assumed to be on the z-axis of the RM Marker.; The zp/xp attribute is exclusive to zv, xv, reuler, and function. Only one of them may be specified.
xp: A Location object or a list of 3 doubles.; Specifies the coordinates of a point on the x-axis of the Marker in the RM Marker coordinate system.; The xp attribute is optional. When not specified, the point is assumed to be on the x-axis of the RM Marker.; The zp/xp attribute is exclusive to zv, xv, reuler, and function. Only one of them may be specified.
usexp: Boolean; The usexp attribute is optional.

When usexp is set to "TRUE", the x-axis of the Marker is calculated first using the QP and XP values. Then the z-axis is computed using QP and ZP such that it is orthonormal to the x-axis. Lastly, the y-axis is computed using the right-hand rule.

When usexp is set to "FALSE" or it is not defined, the z-axis of the Marker is calculated first using the QP and ZP values. Then the x-axis is computed using QP and XP such that it is orthonormal to the z-axis. Lastly, the y-axis is computed using the right-hand rule.
zv: A Location object or a list of 3doubles.; Specifies the z axis direction of the Marker in the RM Marker coordinate system.; The zv attribute is optional. When not specified, the z-axis of the RM Marker will be used.; The zv/xv attributes are exclusive to zp, xp, reuler and function. Only one of them may be specified.
xv: A Location object or a list of 3doubles.; Specifies the x-axis direction of the Marker in the RM Marker coordinate system.; The xv attribute is optional. When not specified, the x-axis of the RM Marker will be used.; The zv/xv attribute is exclusive to zp, xp, reuler, and function. Only one of them may be specified.
usexv: Boolean.; The usexv attribute is optional.

When usexv is set to "TRUE", the x-axis of the Marker is calculated first using xv. Then, the z-axis is computed using zv such that it is orthonormal to the x-axis. Lastly, the y-axis is computed using the right-hand rule.

When usexv is set to "FALSE" or it is not defined, the z-axis of the Marker is calculated first using zv. Then, the x-axis is computed using xv such that it is orthonormal to the z-axis. Lastly, the y-axis is computed using the right-hand rule.

reuler: A list of 3 doubles; Specifies the body-fixed 3-1-3 Euler angles, in radians, of the Marker with respect to the RM Marker.; The reuler attribute is optional. When not specified, it is assumed to be (0,0,0). In other words, the Marker has the same orientation as the RM Marker.; The reuler attribute is exclusive to zv/xv, zp/xp, and function. Only one of them may be specified.

Attributes Defined in a Compiled User-written Subroutine

body: Reference to an existing Part, PointMass or FlexBody object; Specifies an already existing PART, POINT_MASS or FLEX_BODY object to which the Marker belongs.; The body attribute is mandatory
function: String; The list of parameters that are passed from the data file to the user-defined subroutine.; The function attribute is mandatory
routine: String; Specifies an alternative name for the user subroutine. The name consists of two pieces of information, separated by "::". The first is the pathname to the shared library containing the function that computes the response of the user-defined Surface. The second is the name of the function in the shared library that does the computation.; An example is: routine="/staff/Altair/engine.dll::myMarker"

"/staff/Altair/ engine.dll is the dll

myMarker" is the function within this DLL that performs the calculations; The attribute routine is optional.; When not specified, routine defaults to MARKER_READ.; When function is specified, but routine is not, routine defaults to MARKER_READ.

Attributes Defined in a Python Script

body: Reference to an existing Part, PointMass or FlexBody object; Specifies an already existing PART, POINT_MASS or FLEX_BODY object to which the Marker belongs.; The body attribute is mandatory
function: String; The list of parameters that are passed from the data file to the user-defined subroutine.; The function attribute is mandatory
routine: Pointer to a callable function in Python; An example is: routine=myMarker

myMarker is a Python function or method that can be called from wherever the model resides.; The attribute routine is optional.; When not specified, routine defaults to MARKER_READ.

Optional Attributes Available to all Methods

id: Integer; Specifies the element identification number. This number must be unique among all the Marker objects in the model.; This attribute is optional. MotionSolve will automatically create an ID when one is not specified.; Range of values: id > 0
label: String; Specifies the name of the Marker object.; This attribute is optional. When not specified, MotionSolve will create a label for you.
rm: Reference to an existing Marker; Defines the reference coordinate system in which the MARKER location and orientation are described.; If you want to specify the position and orientation of the MARKER in the global reference frame, use RM=0.; The rm attribute is optional. When not specified, the position and orientation of the MARKER is assumed to be with respect to the LPRF of the hosting body.
floating: Boolean; Specifies whether the MARKER is a floating marker or not.; The attribute floating is optional. When not specified it is set to "FALSE".
node: Integer; Specifies the node on the flexible body to which the MARKER is attached.; The node attribute is required only when a Marker is to be placed oat a node on a flexible body. It is not to be used for rigid bodies or point mass bodies.

Examples

Define a marker on a rigid part p1000.

m1012 = Marker (id=1012, label="marker 1012", body=p1000, qp=[1.414,3.142,1.618], 
zp=[101.327,3.142,-2.545], xp=[1.414, 3.142, 101.618])

Define a Marker at the LPRF of part p30303 with the same orientation as the LPRF.

m30303 = Marker (label="joint 3-marker-i", body=p30303)

Define a Marker on Part p30102 in a user written function, MARKER_READ, written in Python.

m30102040 = Marker (id=30102040, label="Marker 2", body=p30102, function="user(1, -0.5, 0.3, 0., 1.57079633, 1.57079633, -1.57079633)", 
routine=marker_read)

The script marker_read.py is defined below:

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

Define a Marker whose location is dependent on design variables.

# DVs_
qpx = Dv (label="X coordinate of Point B", b=40)
qpy = Dv (label="Y coordinate of Point B", b=200)
qpz = Dv (label="Z coordinate of Point B", b=350)

# QP
qp = [qpx, qpy, qpz]

# ZP is along x-axis
zp = [qpx+10, qpy, qpz]

# XP is along z-axis
xp = [qpx, qpy, qpz+10]

# Now define the Marker and hold it in the Python variable markerB
markerB = Marker (body=p1, qp=qp, zp=zp, xp=xp, label="markerB")

Define a Marker, m2, whose location and orientation is the same as another, m1.

m2 = Marker (body=p2, qp=m1.qp, zp=m1.zp, xp=m1.xp, label="m2")

Figure 1.

Comments

See Properties for an explanation about what properties are, why they are used, and how you can extend these.
For a more detailed explanation about Marker, see Reference: Marker.