Reference: Marker

Command ElementModifies a marker element.

Format

<Reference_Marker
id                  = "integer"
pos_x               = "real"
pos_y               = "real"
pos_z               = "real"
a00                 = "real"
a10                 = "real"
a20                 = "real"
a01                 = "real"
a11                 = "real"
a21                 = "real"
a02                 = "real"
a12                 = "real"
a22                 = "real"
rm_id               = "integer">
</Reference_Marker>

Attributes

id
The element identification number (integer>0). This number is unique to all Reference_Marker elements.
pos_x, pos_y, pos_z
The x, y, and z coordinates of the marker origin specified in terms of the global frame. pos_x defines the x-coordinate of the origin, pos_y defines the y-coordinate of the origin, and pos_z defines the z-coordinate of the origin.
a00 a01 a02, a10 a11 a12, a20 a21 a22
Elements of the transformation matrix defining the orientation of the Reference_Marker with respect to the global frame.

{a00 a10 a20} defines directions cosines of the x-axis.

{a01 a11 a21} defines directions cosines of the y-axis.

{a02 a12 a22} defines directions cosines of the z-axis. The nine elements define a 3x3, orthonormal matrix.

This means that the nine numbers must satisfy the following conditions:
• The magnitude of each column is 1.
• Each column is orthogonal (perpendicular) to the other two.
rm_id
Specifies the ID of the Reference_Marker for which the position and orientation of the current marker are to be defined.

Example

The following example modifies a Reference_Marker on a rigid body.

<Reference_Marker
id                  = "1012"
pos_x               = "1.414"
pos_y               = "3.14159"
pos_z               = "1.61804"
a00                 = "0."
a10                 = "1."
a20                 = "0."
a01                 = "0.041630503"
a11                 = "0."
a21                 = "0.99913307"
a02                 = "0.99913307"
a12                 = "0."
a22                 = "-0.04163050">
rm_id               = 101
</Reference_Marker>