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visual3d:tutorials:modeling:plug-in_gait_lower_limb [2024/11/15 16:54] – [Virtual Foot Segment] wikisysopvisual3d:tutorials:modeling:plug-in_gait_lower_limb [2026/02/03 18:34] (current) – [Introduction] wikisysop
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 ====== Plug-In Gait Lower Limb ====== ====== Plug-In Gait Lower Limb ======
  
-\\ +**In it's current form, the segment's definitions (coordinate systems) are exactly those of the Plug-In Gait model in Visual3D. It is however not possible to obtain the //exact// same results as those generated using Vicon's Nexus software due to the use of different [[Visual3D:Documentation:Kinematics_and_Kinetics:Pose_Estimation|pose estimation]] methods.**
-**N.B. While every effort has been made to ensure the correct implementation of the Plug-In Gait model in Visual3D, some differences may still persist, most likely caused by the different pose estimations used within Nexus and Visual3D. Please report any errors to support@has-motion.com.**+
  
-**NOTE:** This tutorial has been updated. The original format can be found [[Visual3D:Documentation:Modeling:Marker_Sets:PiG_LL_Original|here]]. 
  
 ==== Introduction ==== ==== Introduction ====
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 //Workstation// or //Nexus// users will be familiar with the Plug-In Gait variation as Vicon's implementation of the CGM. //Workstation// or //Nexus// users will be familiar with the Plug-In Gait variation as Vicon's implementation of the CGM.
  
-In this tutorial, we describe this implementation of [[http://www.vicon.com%7C|Vicon's]] Plug-In Gait using Visual3D.+In this tutorial, we describe this implementation of [[http://www.vicon.com|Vicon's]] Plug-In Gait using Visual3D.
  
 +To see an example of a modified definition for the Plug-In Gait Lower Limb model to compensate for errors in marker placement, see this [[:plug_gait_lower_limb_modified|tutorial]].
 +
 +A video version of this tutorial can be viewed [[https://youtu.be/Pp8wqqM98L0|here]].
 ==== Pose Estimation ==== ==== Pose Estimation ====
  
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 Since there are variations of the conventional gait model, decisions must be made prior to marker placement and data collection. The diagram below lays out some of the decisions based on body segment. This is not comprehensive since many variations exist. The following sections describe the conventional gait model marker placement locations and challenges based on these options. Since there are variations of the conventional gait model, decisions must be made prior to marker placement and data collection. The diagram below lays out some of the decisions based on body segment. This is not comprehensive since many variations exist. The following sections describe the conventional gait model marker placement locations and challenges based on these options.
  
-{{:Conventional_gait_model_decisions1.png?790x550}}+{{:Conventional_gait_model_decisions1.png?790}}
  
-In the case of the Plug-In Gait, the decisions have already been made for option 2(c), 4(b) and 5(b). Using Visual3D, it is possible to opt for different model decisions if needed or relevant. This would however not be consistent with the Plug-In Gait's implementation per se.+In the case of the Plug-In Gait, the decisions have already been made for option 2%%(c)%%, 4(b) and 5(b). Using Visual3D, it is possible to opt for different model decisions if needed or relevant. This would however not be consistent with the Plug-In Gait's implementation per se.
  
 ==== Manual Metrics For Plug-In Gait ==== ==== Manual Metrics For Plug-In Gait ====
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 **Foot Marker Placement Considerations**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       **Foot Marker Placement Considerations**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
  
-The foot is visualized as a line along the long axis of the foot from the 2nd metatarsal heads and the ankle joint center projected onto the plantar surface of the foot.\\ \\ The forefoot (toe) marker (RTOE, LTOE) is placed on the dorsal aspect on the 2nd metatarsal heads proximal to the MP joint (on the mid-foot side of the equinus break between forefoot and midfoot). Care should be taken in feet with midfoot breakdown or collapse. The placement of this marker should be proximal to the deformity to avoid exaggerating dorsiflexion in stance.\\ \\ The heel marker (RHEE, LHEE) is placed on the calcaneous where the medial/lateral position is in line with the ankle joint center. In a plantargrade foot, the heel marker is at the same height above the plantar surface of the foot as the toe marker. For a non-plantargrade foot as well as shoe/brace conditions, the height of the heel marker must be placed so that the line from the heel to toe (when viewed from the sagittal plane) is parallel to the plantar surface of the foot.\\ \\ **Note that inversion/eversion of the foot cannot be measured reliably with any Conventional Gait Model without any enhancement to the foot marker set**\\ \\ See [[Visual3D:Tutorials:Modeling:Building_a_Conventional_Gait_Model#Enhancing_the_Foot_Segment|Enhancing the foot segment]] for more detail.+The foot is visualized as a line along the long axis of the foot from the 2nd metatarsal heads and the ankle joint center projected onto the plantar surface of the foot.\\ \\ The forefoot (toe) marker (RTOE, LTOE) is placed on the dorsal aspect on the 2nd metatarsal heads proximal to the MP joint (on the mid-foot side of the equinus break between forefoot and midfoot). Care should be taken in feet with midfoot breakdown or collapse. The placement of this marker should be proximal to the deformity to avoid exaggerating dorsiflexion in stance.\\ \\ The heel marker (RHEE, LHEE) is placed on the calcaneous where the medial/lateral position is in line with the ankle joint center. In a plantargrade foot, the heel marker is at the same height above the plantar surface of the foot as the toe marker. For a non-plantargrade foot as well as shoe/brace conditions, the height of the heel marker must be placed so that the line from the heel to toe (when viewed from the sagittal plane) is parallel to the plantar surface of the foot.\\ \\ **Note that inversion/eversion of the foot cannot be measured reliably with any Conventional Gait Model without any enhancement to the foot marker set.**\\ \\ See [[Visual3D:Tutorials:Modeling:Building_a_Conventional_Gait_Model#Enhancing_the_Foot_Segment|Enhancing the foot segment]] for more detail.
  
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 {{:tutorial1_2.jpg}}\\ {{:tutorial1_2.jpg}}\\
  
-  - From the **Model** menu, select **Create (Add Static Calibration File)**\\ +  - From the **Model** menu, select **Hybrid Model from C3DFile** 
-  - Select **Hybrid Model from C3DFile** +  - In the **Select the calibration file for the new model** dialog, select //WalkingStaticLowerBody.c3d//
-  - In the **Select the calibration file for the new model** dialog, select //Sub01_Static_01.c3d//+
     - If using a knee alignment device, select //Sub01_Static_KAD_01.c3d//     - If using a knee alignment device, select //Sub01_Static_KAD_01.c3d//
   - Click **Open.**   - Click **Open.**
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   - Click **Landmarks** button   - Click **Landmarks** button
   - Click **Add New Landmark** button   - Click **Add New Landmark** button
-  - Create Landmark: //RHIP//\\ \\ **Landmark Name:** //RHIP//\\ **Define Orientation Using:** \\    Click **Existing Segment:** //Pelvis// \\ Offset Using the Following **ML/AP/AXIAL** Offsets:\\    **X:** //-HJC_ML//    **Y:** //HJC_AP//    **Z:** //HJC_AX// \\ **Do NOT Check:** //Offset by Percent (1.0 = 100%)// \\ **Check:** //Calibration Only Landmark//+  - Create Landmark: //RHIP//\\ \\ **Landmark Name:** //RHIP//\\ **Define Orientation Using:** \\    Click **Existing Segment:** //Pelvis// \\ Offset Using the Following **ML/AP/AXIAL** Offsets:\\    **X:** //-HJC_ML//    **Y:** //HJC_AP//    **Z:** //HJC_AX// \\ **Do NOT Check:** //Offset by Percent (1.0 = 100%)// \\ **Do NOT Check:** //Calibration Only Landmark//
  
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   - Click **Landmarks** button   - Click **Landmarks** button
   - Click **Add New Landmark** button   - Click **Add New Landmark** button
-  - Create Landmark: //LHIP//\\ \\ **Landmark Name:** //LHIP//\\ **Define Orientation Using:** \\    Click **Existing Segment:** //Pelvis//\\ Offset Using the Following **ML/AP/AXIAL** Offsets:\\    **X:** //HJC_ML//    **Y:** //HJC_AP//    **Z:** //HJC_AX// \\ **Do NOT Check:** //Offset by Percent (1.0 = 100%)// \\ **Check:** //Calibration Only Landmark//+  - Create Landmark: //LHIP//\\ \\ **Landmark Name:** //LHIP//\\ **Define Orientation Using:** \\    Click **Existing Segment:** //Pelvis//\\ Offset Using the Following **ML/AP/AXIAL** Offsets:\\    **X:** //HJC_ML//    **Y:** //HJC_AP//    **Z:** //HJC_AX// \\ **Do NOT Check:** //Offset by Percent (1.0 = 100%)// \\ **Do NOT Check:** //Calibration Only Landmark//
  
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   - In the **Segments** tab, select //Right Thigh// in the Segment Name box.   - In the **Segments** tab, select //Right Thigh// in the Segment Name box.
   - Click on the **Create Segment** button.   - Click on the **Create Segment** button.
-  - In the **Right Thigh** tab, enter these values:\\ \\ **Define Proximal Joint and Radius**\\    **Lateral:** //None//     **Joint:** //RHJC//     **Medial:** //None//     \\    **Radius:** //0.5*DISTANCE(RHJC,LHJC)//\\ **Define Distal Joint and Radius**\\    **Lateral:** //RKNE//     **Joint:** //None//     **Medial:** //None//     \\    **Radius:** //0.5*Knee_Width + MarkerRadius//\\ **Extra Target to Define Orientation**\\    **Location:** //Lateral//     //RTHI//\\ **Select Tracking Targets:**\\ **Check:** //Use Calibration Targets for Tracking//\\ \\+  - In the **Right Thigh** tab, enter these values:\\ \\ **Define Proximal Joint and Radius**\\    **Lateral:** //None//     **Joint:** //RHJC//     **Medial:** //None//     \\    **Radius:** //0.5*DISTANCE(RHJC,LHJC)//\\ **Define Distal Joint and Radius**\\    **Lateral:** //RKNE//     **Joint:** //None//     **Medial:** //None//     \\    **Radius:** //0.5*Knee_Width + MarkerRadius//\\ **Extra Target to Define Orientation**\\    **Location:** //Lateral//     //RTHI// \\ **Select Tracking Targets:**\\ **Check:** //Use Calibration Targets for Tracking//\\ \\
   - Click on **Build Model.**   - Click on **Build Model.**
   - Click on **Close Tab** before proceeding.   - Click on **Close Tab** before proceeding.
visual3d/tutorials/modeling/plug-in_gait_lower_limb.1731689692.txt.gz · Last modified: by wikisysop