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visual3d:documentation:pipeline:model_based_data_commands:angular_momentum_example [2025/12/19 14:43] – wikisysopvisual3d:documentation:pipeline:model_based_data_commands:angular_momentum_example [2026/06/18 21:05] (current) – Linked model-based item pages. richard
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-===== Angular Momentum Examples ===== +====== Angular Momentum Examples ====== 
-This page demonstrates how to compute angular momentum using sports data sets, with normalization methods based on recent biomechanics research. The approach follows principles established in studies like "How maximal whole-body and segmental angular momenta relate to fastball speeds in high school baseball pitchers," which showed that normalized angular momentum (divided by body mass × height × velocity) provides meaningful comparisons across athletes of different sizes. The pipeline computes both segmental angular momentum (with local and remote components) and model angular momentum, then projects these 3D vectors onto task-specific planes—such as the swing plane in batting or a golf swing. This projection isolates the rotational momentum that actually contributes to performance, filtering out off-axis rotation that doesn't transfer energy to the implement or ball. The examples below show how to implement these calculations in Visual3D for batting analysis, though the same principles apply to pitching, throwing, and other rotational sports movements. +This page demonstrates how to compute angular momentum using sports data sets, with normalization methods based on recent biomechanics research. The approach follows principles established in studies like "How maximal whole-body and segmental angular momenta relate to fastball speeds in high school baseball pitchers"[1] and "Changes in angular momentum during the golf swing and their association with club head speed"[2]. The following pipelines computes both segmental angular momentum (with local and remote components) and model angular momentum, then projects these 3D vectors onto the swing planes for both baseball patting and a golf swing. The examples below show how to implement these calculations in Visual3D for batting and golf analysis, though the same principles apply to pitching, throwing, and other rotational sports movements. 
-====Baseball==== + 
-This example shows how to compute the angular momentum of the model (MODEL_ANGULAR_MOMENTUM) as well as finding the angular momentum of a segment (ANGULAR_MOMENTUM) using babseball data with accounting for the swing plane. +=====Example 1: Baseball===== 
-{{:visual3d:documentation:pipeline:model_based_data_commands:basbeall.png?400|}}+This example shows how to compute the angular momentum of the model (the **[[visual3d:documentation:visual3d_signal_types:link_model_based_data_type:model_angular_momentum|MODEL_ANGULAR_MOMENTUM]]** model-based item) as well as finding the angular momentum of a segment (the **[[visual3d:documentation:visual3d_signal_types:link_model_based_data_type:angular_momentum|ANGULAR_MOMENTUM]]** model-based item) using baseball data with accounting for the swing plane. 
 +|{{:visual3d:documentation:pipeline:model_based_data_commands:basbeall.png?400|}}|{{:visual3d:documentation:pipeline:model_based_data_commands:graph.jpg?500x400|}}| 
 ---- ----
  
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 ; ;
 </code> </code>
-4. Using the CONTACT_PLANE calculated in step 2, the **projection** values below represent the magnitude of angular momentum aligned with the swing plane, expressed as a scalar rather then a vector. + 
 +4. The projected values below represent the magnitude of angular momentum aligned with the swing plane calculated in step 2 , expressed as a scalar rather then a vector.
 <code> <code>
 Evaluate_Expression Evaluate_Expression
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 ; ;
 </code> </code>
 +----
 +===== Example 2: Golf ====
  
-====Golf====+1. First, the Best_Fit_Plane is used to calculate the swing plane at impact. This will be used in subsequent commands to identify the angular momentum projection on the swing plane:  
 +<code> 
 +Evaluate_Expression 
 +/EXPRESSION=METRIC_MEAN(SIGN(DOT(VECTOR(LANDMARK::ORIGINAL::VLB_ANTERIOR,0),Best_Fit_Plane(CURRENT_SIGNAL,EVENT_LABEL::SEQUENCE::CONTACT_PLANE)))) 
 +*Best_Fit_Plane(CURRENT_SIGNAL,EVENT_LABEL::SEQUENCE::CONTACT_PLANE) 
 +/SIGNAL_TYPES=KINETIC_KINEMATIC 
 +/SIGNAL_FOLDER=CLUB_FACE 
 +/SIGNAL_NAMES=ProxEndPos 
 +! /SIGNAL_COMPONENTS= 
 +! /RESULT_TYPES=DERIVED 
 +/RESULT_FOLDERS=CLUB 
 +/RESULT_NAME=CONTACT_PLANE 
 +! /APPLY_AS_SUFFIX_TO_SIGNAL_NAME=FALSE 
 +; 
 +</code>
  
-====Segment Angular Momentum About Segment COM====+==== Example 2a: Segment Angular Momentum About Segment COM ==== 
 +The following example show how the angular momentum of the thorax about its own center of mass can be calculated: 
 <code> <code>
 Compute_Model_Based_Data Compute_Model_Based_Data
-/RESULT_NAME=Angular_Segment_Momentum+/RESULT_NAME=Thorax_AngMom
 /SUBJECT_TAG=ALL_SUBJECTS /SUBJECT_TAG=ALL_SUBJECTS
 /FUNCTION=ANGULAR_MOMENTUM /FUNCTION=ANGULAR_MOMENTUM
-/SEGMENT=RFA+/SEGMENT=RTX
 /REFERENCE_SEGMENT= /REFERENCE_SEGMENT=
 ! /RESOLUTION_COORDINATE_SYSTEM=LAB ! /RESOLUTION_COORDINATE_SYSTEM=LAB
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 ! /AXIS2=Y ! /AXIS2=Y
 ! /AXIS3=Z ! /AXIS3=Z
-/INCLUDE_REMOTE_ANGULAR_MOMENTUM=TRUE+! /INCLUDE_REMOTE_ANGULAR_MOMENTUM=FALSE
 ! /TREADMILL_DATA=FALSE ! /TREADMILL_DATA=FALSE
 ! /TREADMILL_DIRECTION=UNIT_VECTOR(0,1,0) ! /TREADMILL_DIRECTION=UNIT_VECTOR(0,1,0)
 ! /TREADMILL_SPEED=0.0 ! /TREADMILL_SPEED=0.0
-</code> 
-====Segment Angular Momentum About Model COM==== 
-<code> 
-First_Derivative 
-/SIGNAL_TYPES=KINETIC_KINEMATIC 
-/SIGNAL_FOLDER=Model 
-/SIGNAL_NAMES=CenterOfMass 
-/RESULT_TYPES=DERIVED 
-/RESULT_FOLDER=COM 
-! /RESULT_NAMES= 
-/RESULT_SUFFIX=_VEL 
 ; ;
 +</code>
  
-! Nested Loops +The resulting segment angular momentum about the z looked like so:
-! Outer Loop gets an active segment+
  
 +{{:visual3d:documentation:pipeline:model_based_data_commands:thx_segment.png?600|}}
  
-For_Each +==== Example 2b: Segment Angular Momentum Including Remote Angular Momentum ====
-/ITERATION_PARAMETER_NAME=SEG_NAME +
-/ITEMS=RFT+RSK+RTH+LFT+LSK+LTH+RPV +
-;+
  
-! compute the R for (r x mv) +This example shows how the angular momentum of the thorax can be found, like above, this time including the remote angular momentum of the segment. The remote angular momentum is defined as a segment’s linear momentum relative to the body’s center of mass. This value is then projected, using Evaluate_Expression, onto the swing plane we defined earlier: 
-Evaluate_Expression +<code> 
-/EXPRESSION=vector((Kinetic_Kinematic::&::SEG_NAME&:&:CGPos::X - KINETIC_KINEMATIC::MODEL::CenterOfMass::X ), (Kinetic_Kinematic::&::SEG_NAME&:&:CGPos::Y - KINETIC_KINEMATIC::MODEL::CenterOfMass::Y), (Kinetic_Kinematic::&::SEG_NAME&:&:CGPos::Z - KINETIC_KINEMATIC::MODEL::CenterOfMass::Z)) +Compute_Model_Based_Data 
-/RESULT_NAME=::SEG_NAME&_R  +/RESULT_NAME=Thorax_AngMomRemote 
-! /RESULT_TYPE=DERIVED +/SUBJECT_TAG=ALL_SUBJECTS 
-! /RESULT_FOLDER=PROCESSED+/FUNCTION=ANGULAR_MOMENTUM 
 +/SEGMENT=RTX 
 +/REFERENCE_SEGMENT= 
 +! /RESOLUTION_COORDINATE_SYSTEM=LAB 
 +! /USE_CARDAN_SEQUENCE=FALSE 
 +/NORMALIZATION=TRUE 
 +/NORMALIZATION_METHOD=DEFAULT_NORMALIZATION 
 +! /NORMALIZATION_METRIC= 
 +! /NEGATEX=FALSE 
 +! /NEGATEY=FALSE 
 +! /NEGATEZ=FALSE 
 +! /AXIS1=X 
 +! /AXIS2=Y 
 +! /AXIS3=Z 
 +/INCLUDE_REMOTE_ANGULAR_MOMENTUM=TRUE 
 +! /TREADMILL_DATA=FALSE 
 +! /TREADMILL_DIRECTION=UNIT_VECTOR(0,1,0) 
 +! /TREADMILL_SPEED=0.0
 ; ;
  
-! compute mv 
 Evaluate_Expression Evaluate_Expression
-/EXPRESSION=(MODEL::SEGMENT::&::SEG_NAME&:&:MASS)*(Kinetic_Kinematic::&::SEG_NAME&:&:CGVel - DERIVED::COM::CENTEROFMASS_VEL) +/EXPRESSION=DOT(DERIVED::CLUB::CONTACT_PLANE,VECTOR(CURRENT_SIGNAL,0)) 
-/RESULT_NAME=::SEG_NAME&_mv +/SIGNAL_TYPES=LINK_MODEL_BASED 
-! /RESULT_TYPE=DERIVED +! /SIGNAL_FOLDER=ORIGINAL 
-! /RESULT_FOLDER=PROCESSED+/SIGNAL_NAMES=Thorax_AngMomRemote 
 +! /SIGNAL_COMPONENTS= 
 +! /RESULT_TYPES=DERIVED 
 +/RESULT_FOLDERS=CLUB 
 +/RESULT_NAME=_PROJ 
 +/APPLY_AS_SUFFIX_TO_SIGNAL_NAME=TRUE
 ; ;
  
-! compute rxmv +</code>
-Evaluate_Expression +
-/EXPRESSION=cross(DERIVED::PROCESSED::&::SEG_NAME&_R, DERIVED::PROCESSED::&::SEG_NAME&_mv) +
-/RESULT_NAME=::SEG_NAME&_rxmv +
-! /RESULT_TYPE=DERIVED +
-! /RESULT_FOLDER=PROCESSED +
-;+
  
 +It is important to note that when remote angular momentum is included the value is only particularly meaningful around the time of impact. The resulting projected value around the time of impact looked like so:
 +
 +{{:visual3d:documentation:pipeline:model_based_data_commands:remote_projection.png?600|}}
 +
 +==== Example 2c: Whole Body Angular Momentum About Model COM ====
 +
 +The following commands show how the total angular momentum of the model can be found by summing the angular momentum of every model segment about the model COM. This value is then projected onto the swing plane using the same method as above. Model angular momentum can either include or exclude the remote angular momentum of each segment, in this example it is excluded. 
 +<code>
 Compute_Model_Based_Data Compute_Model_Based_Data
-/RESULT_NAME=::SEG_NAME&_IW +/RESULT_NAME=AngMomTotal 
-/FUNCTION=ANGULAR_MOMENTUM +/SUBJECT_TAG=ALL_SUBJECTS 
-/SEGMENT=::SEG_NAME +/FUNCTION=MODEL_ANGULAR_MOMENTUM 
-/REFERENCE_SEGMENT=LAB+/SEGMENT= 
 +/REFERENCE_SEGMENT=
 ! /RESOLUTION_COORDINATE_SYSTEM=LAB ! /RESOLUTION_COORDINATE_SYSTEM=LAB
 ! /USE_CARDAN_SEQUENCE=FALSE ! /USE_CARDAN_SEQUENCE=FALSE
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 ! /AXIS2=Y ! /AXIS2=Y
 ! /AXIS3=Z ! /AXIS3=Z
 +! /INCLUDE_REMOTE_ANGULAR_MOMENTUM=FALSE
 +! /TREADMILL_DATA=FALSE
 +! /TREADMILL_DIRECTION=UNIT_VECTOR(0,1,0)
 +! /TREADMILL_SPEED=0.0
 ; ;
  
-! compute rxmv 
 Evaluate_Expression Evaluate_Expression
-/EXPRESSION=LINK_MODEL_BASED::ORIGINAL::&::SEG_NAME&_IW + DERIVED::PROCESSED::&::SEG_NAME&_rxmv +/EXPRESSION=DOT(DERIVED::CLUB::CONTACT_PLANE,VECTOR(CURRENT_SIGNAL,0)) 
-/RESULT_NAME=::SEG_NAME&_IW +/SIGNAL_TYPES=LINK_MODEL_BASED 
-/RESULT_TYPE=DERIVED +! /SIGNAL_FOLDER=ORIGINAL 
-/RESULT_FOLDER=Momentum_Contribution+/SIGNAL_NAMES=AngMomTotal 
 +! /SIGNAL_COMPONENTS= 
 +! /RESULT_TYPES=DERIVED 
 +/RESULT_FOLDERS=CLUB 
 +/RESULT_NAME=_PROJ 
 +/APPLY_AS_SUFFIX_TO_SIGNAL_NAME=TRUE
 ; ;
 +</code>
  
-End_For_Each +The resulting projection of the model angular momentum on the swing plane looked like so:
-/ITERATION_PARAMETER_NAME=SEG_NAME +
-;+
  
-</code>+{{:visual3d:documentation:pipeline:model_based_data_commands:total_projection.png?600|}}
  
-====Whole Body Angular Momentum About Model COM====+A comparison of the angular momentum about the z axis for each of these examples can be seen below:
  
 +{{:visual3d:documentation:pipeline:model_based_data_commands:golf_angular_momentum.png?600|}}
  
 +===== References =====
 +[1] [[https://pubmed.ncbi.nlm.nih.gov/40858090/|How maximal whole-body and segmental angular momenta relate to fastball speeds in high school baseball pitchers]]\\
 +[2] [[https://www.researchgate.net/publication/337863270_Changes_in_angular_momentum_during_the_golf_swing_and_their_association_with_club_head_speed|Changes in angular momentum during the golf swing and their association with club head speed]]
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