visual3d:documentation:modeling:segments:coda_pelvis
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| visual3d:documentation:modeling:segments:coda_pelvis [2024/06/14 17:24] – created sgranger | visual3d:documentation:modeling:segments:coda_pelvis [2024/07/17 15:45] (current) – created sgranger | ||
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| - | |**Language: | + | ====== |
| - | |===== Contents =====\\ \\ \\ \\ * [[# | + | |{{:CodaPelvisScs.gif}}|The CODA pelvis refers to a pelvis segment model used by Charnwood Dynamics that they requested that we implement. The pelvis segment is defined using the anatomical locations of the ASIS (Anterior Superior Iliac Spine) and the PSIS (Posterior Superior Iliac Spine). These landmarks are bony protuberances on the Pelvis bones that can be palpated on most (but not all) subjects. They are particularly useful if the subject is very thin, a cadaver, or a skeleton, and historically have been the reference points for defining the segment coordinate system for many experimental studies focused on determining regression equations for locating the hip joint centers. **Unfortunately, |
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| - | ===== Pelvis Origin | + | ==== Pelvis Origin ==== |
| The origin of the pelvis segment coordinate system is defined as the mid-point between the ASIS markers. When creating the Coda pelvis the user can enter the offset of the radius of the motion capture markers. This will create the ORIGIN at the midpoint of the ASIS anatomically rather than the mid-point of the motion capture markers. (The value of the marker radius gets stored as a Subject/ | The origin of the pelvis segment coordinate system is defined as the mid-point between the ASIS markers. When creating the Coda pelvis the user can enter the offset of the radius of the motion capture markers. This will create the ORIGIN at the midpoint of the ASIS anatomically rather than the mid-point of the motion capture markers. (The value of the marker radius gets stored as a Subject/ | ||
| - | ===== Pelvis Orientation | + | ==== Pelvis Orientation ==== |
| The (x-y) plane of the segment coordinate system is defined as the plane passing through the right and left ASIS markers, and the mid-point of the right and left PSIS markers. | The (x-y) plane of the segment coordinate system is defined as the plane passing through the right and left ASIS markers, and the mid-point of the right and left PSIS markers. | ||
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| If the markers have been placed accurately, the pelvis segment coordinate system will typically be tilted forward about 20 degrees, which is unfortunate for the calculation of the hip angle, but can be resolved using virtual segments ([[Visual3D: | If the markers have been placed accurately, the pelvis segment coordinate system will typically be tilted forward about 20 degrees, which is unfortunate for the calculation of the hip angle, but can be resolved using virtual segments ([[Visual3D: | ||
| - | ===== Hip Joint Landmarks | + | ==== Hip Joint Landmarks ==== |
| Estimates for the Right and Left Hip Joint Center are represented as Landmarks that are created automatically when the CODA pelvis segment is created. The location of the landmark is defined as:\\ | Estimates for the Right and Left Hip Joint Center are represented as Landmarks that are created automatically when the CODA pelvis segment is created. The location of the landmark is defined as:\\ | ||
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| - | ===== Specifying the ASIS distance | + | ==== Specifying the ASIS distance ==== |
| For some subjects the ASIS markers may be difficult to place precisely on the ASIS, so they get placed laterally. | For some subjects the ASIS markers may be difficult to place precisely on the ASIS, so they get placed laterally. | ||
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| This results in an ASIS distance that is too big, and this directly affects the location of the Hip Landmark. | This results in an ASIS distance that is too big, and this directly affects the location of the Hip Landmark. | ||
| - | The ASIS distance is a [[Model_Metrics_|Model Metric]] value that can be modified. | + | The ASIS distance is a [[Visual3D: |
| Switch to the Model Metrics Tab: | Switch to the Model Metrics Tab: | ||
| - | [[File: | + | {{:ModelMetricsDlg.jpg}} |
| Select the ASIS_Distance item and select the Modify button | Select the ASIS_Distance item and select the Modify button | ||
| - | [[File: | + | {{:ASISDistance1.png}} |
| Enter the measured value of the ASIS distance. | Enter the measured value of the ASIS distance. | ||
| - | [[File: | + | {{:ASISDistance2.png}} |
| The hip landmark will be based on this ASIS distance. | The hip landmark will be based on this ASIS distance. | ||
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| - | Retrieved from "" | ||
visual3d/documentation/modeling/segments/coda_pelvis.1718385864.txt.gz · Last modified: 2024/06/14 17:24 by sgranger