These array and matrix functions can be used anywhere Visual3D allows expressions to be used.

Arrays can be thought of as a 1-dimensional ordered list of numerical values.

Vector(a,b, etc) - creates a vector of the number of components specified

! Create a metric signal with 2 components and one frame
Metric_Explicit
! /RESULT_METRIC_FOLDER=PROCESSED
/RESULT_METRIC_NAME=VEC2
/METRIC_VALUE=2+3
;

! Create a vector containing a constant, a two dimensional metric and a 3 dimensional model based signal.
Evaluate_Expression
/EXPRESSION=vector (1, METRIC::PROCESSED::VEC2, LINK_MODEL_BASED::ORIGINAL::RKNEE_ANGLE)
! /SIGNAL_TYPES=
! /SIGNAL_FOLDER=ORIGINAL
! /SIGNAL_NAMES=
! /RESULT_TYPES=DERIVED
! /RESULT_FOLDERS=PROCESSED
/RESULT_NAME=TEST
! /APPLY_AS_SUFFIX_TO_SIGNAL_NAME=FALSE
;

The resulting signal will have the first three columns (one for the constant, one for the vector of 2 components) buffered to the number of frames of RKNEE_ANGLE by replicating the first frame.

list(a,b,etc) - creates a list (column vector) of the number of rows specified.

unit_vector (a, b, etc) - creates a unit vector of the number of components specified.

Rotation matrices are used throughout Visual3D because they can entirely contain the information regarding a segment's pose.

Rotation_Multiply(a,b) - Multiplies two rotation matrices

Example: Multiply two ROTATION signals

Evaluate_Expression
/EXPRESSION=ROTATION_MULTIPLY(ROTATION_INVERSE(ROTATION::ORIGINAL::PELVIS_SHIFTED_4x4),CURRENT_SIGNAL)
/SIGNAL_TYPES=ROTATION
! /SIGNAL_FOLDER=ORIGINAL
! /SIGNAL_NAMES=
/RESULT_TYPES=ROTATION
! /RESULT_FOLDERS=PROCESSED
/RESULT_NAME=_MULT
/APPLY_AS_SUFFIX_TO_SIGNAL_NAME=TRUE
;

Rotation_Inverse(a) - Calculates the inverse of a rotation matrix

Example: Inverse of a 4×4 ROTATION signal or a 3×3 LINK_MODEL_BASED ROTATION

Evaluate_Expression
/EXPRESSION=ROTATION_INVERSE(ROTATION::ORIGINAL::PELVIS_SHIFTED_4x4)
/SIGNAL_TYPES=ROTATION
! /SIGNAL_FOLDER=ORIGINAL
! /SIGNAL_NAMES=
/RESULT_TYPES=ROTATION
! /RESULT_FOLDERS=PROCESSED
/RESULT_NAME=_INV
/APPLY_AS_SUFFIX_TO_SIGNAL_NAME=TRUE
;

Note: A good description of the inverse of a ROTATION signals can be found here

Rotation_Transpose(a) - Creates the transposition of a rotation matrix.

Example: Transpose of a 3×3 LINK_MODEL_BASED ROTATION signal

Evaluate_Expression
/EXPRESSION=ROTATION_TRANSPOSE(ROTATION::ORIGINAL::PELVIS_SHIFTED_4x4)
/SIGNAL_TYPES=ROTATION
! /SIGNAL_FOLDER=ORIGINAL
! /SIGNAL_NAMES=
/RESULT_TYPES=ROTATION
! /RESULT_FOLDERS=PROCESSED
/RESULT_NAME=_T
/APPLY_AS_SUFFIX_TO_SIGNAL_NAME=TRUE
;

Pose4x4(a,0,0,0,123) - Creates a 4×4 rotation signal based on translation by a signal “a” and the orientation defined by Euler angles (0,0,0) with the Euler sequence 123.

This function was created in support of the shadow segments feature.

Example: Create a rotation matrix for a shadow segment of the right heel

POSE4X4(R_HEEL,0,0,0,123)

Go back to see other Expression functions.