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--- visual3d:documentation:modeling:segments:segment_properties [2024/06/17 18:17] – created sgranger
+++ visual3d:documentation:modeling:segments:segment_properties [2025/06/20 16:14] (current) – [Segment Properties Dialog] wikisysop
@@ Line 1: / Line 1: @@
+====== Segment Properties ======
+Segment properties include the segment's inertial properties as well as its decorations.
+===== General Properties =====
+^ Property ^ Description ^
+| Segment Name | Every segment has a name. See Visual3D's [[Visual3D:Documentation:Modeling:Segments:Segment_Default_Names|default segment names]]. |
+| Kinetic/Kinematic | Indicates whether or not the segment should be included in the kinetic chain for [[visual3d:documentation:kinematics_and_kinetics:inverse_dynamics|inverse dynamics]]. "Kinematic-only" segments are also called [[visual3d:documentation:modeling:segments:virtual_segments|virtual segments]]. |
-The segment properties include the inertial properties of the segment and its decorations:
+===== Inertial Properties =====
-  * Name See also: [[Visual3D:Documentation:Modeling:Segments:Segment_Default_Names|Segment Default Names]]
+^ Property ^ Description ^
-  * Mass
+| [[Visual3D:Documentation:Modeling:Segments:Segment_Mass|Segment Mass]] | The default segment masses are relative to total body mass according to Dempster's regression equations. |
-  * Geometry
+| Segment Length | Defined exclusively by the [[Visual3D:Documentation:Modeling:Segments:Segment_Coordinate_System|segment definition]] and not editable by the user. |
-  * Center of Mass
+| [[Visual3D:Documentation:Modeling:Segments:Segment_Geometry|Segment Geometry]] | Visual3D models segments as cones, cylinders, spheres, and ellipsoids and uses this geometry to calculate the segment's mass, moments of inertia (IXX, IYY, IZZ) and center of gravity. |
-  * Moment of Inertia
+| [[Visual3D:Documentation:Modeling:Segments:Segment_Inertia|Inertial Values]] | By default the moment of inertia of a segment is computed from the segment mass, the proximal and distal radii, and the Segment Geometry. The default Visual3D segments are treated as geometric objects that have inertial properties based on their shape according to Hanavan. |
-  * Wireframe animation model
+| Center of Mass | The segment's centre of mass is determined automatically from the segment geometry. |
-Note: the inertial properties are computed using geometric primitives.
+Segment and laboratory coordinate systems [[Visual3D:Documentation:Modeling:Segments:Modify_Segment_Coordinate_System|can be modified]] to suit your preferred model.
-**Hanavan E. (1964) A Mathematical Model for the Human Body. Technical Report, Wright-Patterson Air Force Base.**
+===== Animation Properties =====
-Length might be considered a segment property, but the length is defined by the [[Visual3D:Documentation:Modeling:Segments:Segment_Coordinate_System|segment definition]] and is not editable by the user.
-===== Segment Mass =====
+A surface mesh can be associated with each segment as an [[Visual3D:Documentation:Modeling:Segments:Animation_Surface_Models|animation surface model]]. This surface mesh should be stored as a [[Visual3D:Documentation:Modeling:Segments:Wavefront_obj_file_format|Wavefront .obj file]] and [[Visual3D:Documentation:Modeling:Segments:Transforming_an_obj_file|transformed]] as necessary to align with the segment's coordinate system.
-The default segment masses are relative to total body mass (Dempster). See [[Visual3D:Documentation:Modeling:Segments:Segment_Mass|Segment Mass]] for the relative values.
+===== Segment Properties Interface =====
-===== Segment Geometry =====
+The **Segment Properties** portion of Visual3D's [[visual3d:documentation:definitions:model_builder_mode|model-builder mode]] allows users to inspect and modify segment properties which are common to most segments.
-Visual3D models segments as cones, cylinders, spheres, and ellipsoids. VISUAL3D calculates the mass, moments of inertia (IXX, IYY, IZZ) and center of gravity location for each segment. Refer to [[Visual3D:Documentation:Modeling:Segments:Segment_Geometry|Segment Geometry]] for the details.
+{{:visual3d_segment_properties.png}}
-===== Segment Inertia =====
+  - Select the segment name in the **Segment Name** combo box. The selected segment's properties will be displayed in the dialog.
+  - Make the desired changes in the dialog to any of the following properties:
-By default the moment of inertia of a segment is computed from the segment mass, the proximal and distal radii, and the Segment Geometry. The default Visual3D segments are treated as geometric objects that have inertial properties based on their shape (Hanavan E. (1964) A Mathematical Model for the Human Body. Technical Report, Wright-Patterson Air Force Base). Refer to [[Visual3D:Documentation:Modeling:Segments:Segment_Inertia|Segment Inertia]] for more details.
+    - [[Visual3D:Documentation:Modeling:Segments:Segment_Geometry|Segment Geometry]] - The segment may be represented internally as a CONE, .CYLINDER, SPHERE, ELLIPSOID or CUSTOM SEG (ment). The geometry of a segment affects the segment's inertial properties and center of mass location. This also affects the segment geometry drawn when view segment geometry is selected in the animation/model builder window.
+    - [[Visual3D:Documentation:Modeling:Segments:Segment_Mass|Segment Mass]] - The segment mass is defaulted based on the type of segment and the subject mass. To change this value, you may type in a specific value for the mass (in kilograms), or use a formula using existing Subject Data (such as a percentage of the subject mass).
-===== Modify Segment Coordinate System =====
+    - [[Visual3D:Documentation:Modeling:Segments:Segment_Inertia|Inertial Values]] - These values may be modified only for segments with a CUSTOM SEG (ment) selected for the Segment Geometry.
+    - [[Visual3D:Documentation:Modeling:Segments:Segment_Geometry|Distance from CM (Center of Mass) to Proximal end]] - This is a multiplier used to modify the distance from the center of mass from the segment's proximal end. This field is only used when CUSTOM SEG (ment) is selected for the Segment Geometry.
-Segment and laboratory coordinate systems can be modified to suit your preference. Refer to [[Visual3D:Documentation:Modeling:Segments:Modify_Segment_Coordinate_System|Modify Segment Coordinate System]] for more details.
+    - [[Visual3D:Documentation:Modeling:Segments:Animation_Surface_Models|Model File/Material File]] - This is the graphic model file (.obj or .wrl) used to draw the segment in the animation/model window.
+  - Click the **Apply** button.
-===== Animation Surface Models =====
-A surface mesh can be associated with each segment. Refer to [[Visual3D:Documentation:Modeling:Segments:Animation_Surface_Models|Animation Surface Models]] for details.
-==== Wavefront obj file format ====
-Refer to [[Visual3D:Documentation:Modeling:Segments:Wavefront_obj_file_format|Wavefront_obj_file_format]] for how to export for use in Visual3D.
-==== Transforming an obj file ====
-The [[Visual3D:Documentation:Modeling:Segments:Transforming_an_obj_file|Transforming an obj file]] shows a very simple obj file that describes the polygons for a cone.
-===== Segment Properties Example1 =====
-This page specifies segment properties from pipeline commands. Specifically, depth measures for the Pelvis and Thorax.
-**NOTE:** As of Visual3Dv5.01.20, user's are able to enter equations into the depth measurements for the Pelvis and Thorax.
-===== Modify Segment Properties =====
-The **Segment Properties** dialog modifies general segment properties which are common to most segments.
-[[SegmentPropertiesDialog.png]]\\
-To modify a segment's properties, select the segment name in the **Segment Name** combo box. The selected segment's properties will be displayed in the dialog.
-To modify the properties, make the desired change in the dialog, and click the **Apply** button.
-The following properties may be modified:
-  * [[Visual3D:Documentation:Modeling:Segments:Segment_Geometry|Segment Geometry]] - The segment may be represented internally as a CONE, .CYLINDER, SPHERE, ELLIPSOID or CUSTOM SEG (ment). The geometry of a segment affects the segment's inertial properties and center of mass location. This also affects the segment geometry drawn when view segment geometry is selected in the animation/model builder window.
-  * [[Visual3D:Documentation:Modeling:Segments:Segment_Mass|Segment Mass]] - The segment mass is defaulted based on the type of segment and the subject mass. To change this value, you may type in a specific value for the mass (in kilograms), or use a formula using existing Subject Data (such as a percentage of the subject Mass).
-  * [[Visual3D:Documentation:Modeling:Segments:Segment_Length|Segment Length]] - This is computed based upon the calibration of the segment proximal and distal endpoints.
-  * [[Visual3D:Documentation:Modeling:Segments:Segment_Inertia|Inertial Values]] - This is computed based upon the segment mass and geometry. These values may be modified only for segments with a CUSTOM SEG (ment) selected for the Segment Geometry.
-  * [[Visual3D:Documentation:Modeling:Segments:Segment_Geometry|Distance from CM (Center of Mass) to Proximal end]] - This is a multiplier used to modify the distance from the center of mass from the segment's proximal end. This field is only used when CUSTOM SEG (ment) is selected for the Segment Geometry.
-  * [[Visual3D:Documentation:Modeling:Segments:Animation_Surface_Models|Model File/Material File]] - This is the graphic model file (.obj or .wrl) used to draw the segment in the animation/model window.
+Note that some properties cannot be modified directly:
+  - [[Visual3D:Documentation:Modeling:Segments:Segment_Length|Segment Length]] - This is computed based upon the calibration of the segment proximal and distal endpoints.
+  - [[Visual3D:Documentation:Modeling:Segments:Segment_Inertia|Inertial Values]] - This is computed based upon the segment mass and geometry. These values may be modified only for segments with a CUSTOM SEG (ment) selected for the Segment Geometry.
+===== Pipeline Command =====
+Users can define and modify segment properties using the [[visual3d:documentation:pipeline:model_commands:set_segment_properties|Set_Segment_Properties]] pipeline command. As of Visual3D v5.01.20, users are able to enter equations into the depth measurements for the Pelvis and Thorax.
+===== References =====
+  - Dempster W.T. (1955) Space requirements of the seated operator : geometrical, kinematic, and mechanical aspects of the body, with special reference to the limbs. Technical Report, Wright-Patterson Air Force Base.
+  - Hanavan E. (1964) A Mathematical Model for the Human Body. Technical Report, Wright-Patterson Air Force Base