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--- visual3d:documentation:pipeline:metric_commands:metric_cross_product [2024/07/03 17:41] – created sgranger
+++ visual3d:documentation:pipeline:metric_commands:metric_cross_product [2025/10/03 17:35] (current) – [Example: Computing Step Length from Stride Vectors Using Dot Product] wikisysop
@@ Line 1: / Line 1: @@
-====== Metric_Cross_Product ======
+====== Metric Cross Product ======
-Creates a cross product of two metric vectors.
+====Overview====
+The Metric Cross Product command is used to create a cross product of two metric vectors. This could include finding the torque acting on a joint or other similar uses. The command can be found within the **Pipeline Workshop** in the **Metric** folder. The command acts on the active files.
-The command acts on the active files.
+====Pipeline Command====
-{{MetricCrossProductDlg.png}}
+The command, as seen in the pipeline workshop, is below.
 <code>
 Metric_Cross_Product
-/RESULT_METRIC_NAME=The name of the result signal
+! /RESULT_FILE=
-! /RESULT_METRIC_FOLDER=The name of the result signal folder
+! /RESULT_METRIC_FOLDER=PROCESSED
-! /METRIC1_FILE=The movement trial containing the first metric value
+/RESULT_METRIC_NAME=
-/METRIC1_NAME=The name of the metric signal to be evaluated
+! /METRIC1_FILE=
-! /METRIC1_FOLDER=The name of the metric signal folder
+! /METRIC1_FOLDER=PROCESSED
-! /METRIC2_FILE=The movement trial containing the second metric value
+/METRIC1_NAME=
-/METRIC2_NAME=The name of the metric signal folder
+! /METRIC2_FILE=
-! /METRIC2_FOLDER=The name of the metric signal folder
+! /METRIC2_FOLDER=PROCESSED
-! /DIVIDE_BY_METRIC2_LENGTH=(True or False) Divide the resulting signal by the length of the second metric
+/METRIC2_NAME=
-! /GENERATE_MEAN_AND_STDDEV=(True or False)Generate the mean and standard deviation for all of the metrics created
+! /DIVIDE_BY_METRIC2_LENGTH=TRUE
-! /APPEND_TO_EXISTING_VALUES=(True or False)Append this list of metrics to an existing metric of the same result name
+! /GENERATE_MEAN_AND_STDDEV=TRUE
-! /GENERATE_VECTOR_LENGTH_METRIC=(True or False)
+! /APPEND_TO_EXISTING_VALUES=FALSE
-! /RETAIN_NO_DATA_VALUES=(True or False)
+! /GENERATE_VECTOR_LENGTH_METRIC=FALSE
+! /RETAIN_NO_DATA_VALUES=FALSE
 ;
 </code>
+====Command Parameters====
+The following table shows the command parameters seen above and their descriptions:
+|**RESULT_METRIC_NAME**|**The name of the result signal**|
+|**RESULT_METRIC_FOLDER**|**The name of the result signal folder**|
+|**METRIC1_FILE**|**The movement trial containing the first metric value**|
+|**METRIC1_NAME**|**The name of the signal containing the first metric value**|
+|**METRIC1_FOLDER**|**The name of the metric signal folder**|
+|**DIVIDE_BY_METRIC2_LENGTH**|**(True or False) Divide the resulting signal by the length of the second metric**|
+|**GENERATE_MEAN_AND_STDDEV**|**(True or False)Generate the mean and standard deviation for all of the metrics created**|
+|**APPEND_TO_EXISTING_VALUES**|**(True or False)Append this list of metrics to an existing metric of the same result name**|
+|**GENERATE_VECTOR_LENGTH_METRIC**|**(True or False)Generate metric value for vector length**|
+|**RETAIN_NO_DATA_VALUES**|**In cases where there is NO_DATA at an event, you need to specify the parameter /Retain_No_Data_Values=TRUE should you want this included in the resulting signal.**|
+====Dialog====
+The command can be edited in a text editor or in a dialog form. To edit in the dialog pop up form either click on the **Edit** button in the pipeline workshop or double-click on the pipeline command. The dialog is shown below.
+{{:MetricCrossProductDlg.png}}
+The dialog box allows you to assign values to the command parameters outlined above.
 === Metric_File ===
@@ Line 39: / Line 63: @@
 The results are concatenated to an existing signal.
+====Example: Computing Step Length from Stride Vectors Using Dot Product====
+In this example the **Metric Cross Product** command is used along with **Metric Vector Between Events** and **Automatic Gait Events** to find the width of each step in a gait trial.
+First all files are selected as active and key gait events are defined for each trial:
+<code>
+Select_Active_File
+/FILE_NAME=ALL_FILES
+;
+Automatic_Gait_Events
+! /FRAME_WINDOW=8
+! /USE_TPR=TRUE
+! /TPR_EVENT_INSTANCE=1
+;
+</code>
+Next **Metric Vector Between Events** is used twice for each side to define vectors for the proximal end of each foot between gait events:
+<code>
+Metric_Vector_Between_Events
+/START_SIGNAL_TYPE=KINETIC_KINEMATIC
+/START_SIGNAL_NAME=ProxEndPos
+/START_SIGNAL_FOLDER=LFT
+/END_SIGNAL_TYPE=KINETIC_KINEMATIC
+/END_SIGNAL_NAME=ProxEndPos
+/END_SIGNAL_FOLDER=LFT
+/EVENT_SEQUENCE=LHS+LHS
+/EXCLUDE_EVENTS=
+/METRIC_NAME=StrideVectors
+! /GENERATE_MEAN_AND_STDDEV=TRUE
+! /APPEND_TO_EXISTING_VALUES=FALSE
+! /GENERATE_VECTOR_LENGTH_METRIC=FALSE
+;
+Metric_Vector_Between_Events
+/START_SIGNAL_TYPE=KINETIC_KINEMATIC
+/START_SIGNAL_NAME=ProxEndPos
+/START_SIGNAL_FOLDER=RFT
+/END_SIGNAL_TYPE=KINETIC_KINEMATIC
+/END_SIGNAL_NAME=ProxEndPos
+/END_SIGNAL_FOLDER=RFT
+/EVENT_SEQUENCE=RHS+RHS
+/EXCLUDE_EVENTS=
+/METRIC_NAME=StrideVectors
+! /GENERATE_MEAN_AND_STDDEV=TRUE
+/APPEND_TO_EXISTING_VALUES=TRUE
+! /GENERATE_VECTOR_LENGTH_METRIC=FALSE
+;
+Metric_Vector_Between_Events
+/START_SIGNAL_TYPE=KINETIC_KINEMATIC
+/START_SIGNAL_NAME=ProxEndPos
+/START_SIGNAL_FOLDER=RFT
+/END_SIGNAL_TYPE=KINETIC_KINEMATIC
+/END_SIGNAL_NAME=ProxEndPos
+/END_SIGNAL_FOLDER=LFT
+/EVENT_SEQUENCE=RHS+LHS
+/EXCLUDE_EVENTS=
+/METRIC_NAME=LeftStep
+/GENERATE_MEAN_AND_STDDEV=FALSE
+! /APPEND_TO_EXISTING_VALUES=FALSE
+! /GENERATE_VECTOR_LENGTH_METRIC=FALSE
+;
+Metric_Vector_Between_Events
+/START_SIGNAL_TYPE=KINETIC_KINEMATIC
+/START_SIGNAL_NAME=ProxEndPos
+/START_SIGNAL_FOLDER=LFT
+/END_SIGNAL_TYPE=KINETIC_KINEMATIC
+/END_SIGNAL_NAME=ProxEndPos
+/END_SIGNAL_FOLDER=RFT
+/EVENT_SEQUENCE=LHS+RHS
+/EXCLUDE_EVENTS=
+/METRIC_NAME=RightStep
+/GENERATE_MEAN_AND_STDDEV=FALSE
+! /APPEND_TO_EXISTING_VALUES=FALSE
+! /GENERATE_VECTOR_LENGTH_METRIC=FALSE
+;
+</code>
+Now that the vectors for the feet have been defined, **Metric Cross Product** can be used to compute the dot product of those vectors and determine the step width for each stride:
+<code>
+! Calculate LeftStepWidth by taking cross product of LeftStep vector and StrideVectors_MEAN
+! Generate Mean and STD DEV
+Metric_Cross_Product
+! /METRIC1_FILE=
+/METRIC1_NAME=LeftStep
+! /METRIC1_FOLDER=PROCESSED
+/METRIC2_FILE=GLOBAL
+/METRIC2_NAME=StrideVectors_MEAN
+! /METRIC2_FOLDER=PROCESSED
+! /DIVIDE_BY_METRIC2_LENGTH=TRUE
+/RESULT_METRIC_NAME=LeftStepWidth
+! /RESULT_METRIC_FOLDER=PROCESSED
+! /GENERATE_MEAN_AND_STDDEV=TRUE
+! /APPEND_TO_EXISTING_VALUES=FALSE
+/GENERATE_VECTOR_LENGTH_METRIC=TRUE
+;
+! Calculate RightStepWidth by taking cross product of RightStep vector and StrideVectors_MEAN
+! Generate Mean and STD DEV
+Metric_Cross_Product
+! /METRIC1_FILE=
+/METRIC1_NAME=RightStep
+! /METRIC1_FOLDER=PROCESSED
+/METRIC2_FILE=GLOBAL
+/METRIC2_NAME=StrideVectors_MEAN
+! /METRIC2_FOLDER=PROCESSED
+! /DIVIDE_BY_METRIC2_LENGTH=TRUE
+/RESULT_METRIC_NAME=RightStepWidth
+! /RESULT_METRIC_FOLDER=PROCESSED
+! /GENERATE_MEAN_AND_STDDEV=TRUE
+! /APPEND_TO_EXISTING_VALUES=FALSE
+/GENERATE_VECTOR_LENGTH_METRIC=TRUE
+;
+</code>
+The **METRIC:PROCESSED** folder should now contain several new metrics including 3 values (vector, mean, and std dev) for right and left step width. The results should look similar to below:
+{{:visual3d:documentation:pipeline:metric_commands:left_step_width.png?600|}}{{:visual3d:documentation:pipeline:metric_commands:left_step_width_mean.png?600|}}
+A more complete example including dot products is available [[visual3d:documentation:pipeline:signal_commands:mimicking_temporal_distance_command|here]].