Differences

This shows you the differences between two versions of the page.

--- visual3d:documentation:pipeline:force_commands:entering_inertial_values_using_expressions [2024/07/17 15:45] – created sgranger
+++ visual3d:documentation:pipeline:force_commands:entering_inertial_values_using_expressions [2025/07/03 16:19] (current) – Initial recovery from the Wayback Machine. wikisysop
@@ Line 1: / Line 1: @@
-Under Construction...
+====== Entering Inertial Values Using Expressions ======
+It is possible to include any regression equations for the inertia and center of mass because Visual3D allows the user to put expressions into the edit boxes. Consider a typical right thigh segment, which is populated with the default inertial values.
+InertiaExpression1.jpg
+If the user selects this segment to be a CUSTOM_SEG, the edit boxes can be edited.
+InertiaExpression2.jpg
+===== Example: Frustra of Right Cones =====
+For the sake of this example, we will create an expression for the Axial component of the center of mass based on the default computations described elsewhere in the documentation
+frustraOfRightCones1.gif
+frustraOfRightCones2.png
+For convenience create a new Subject Metric X and enter the expression RTH_DISTAL_RADIUS/RTH_PROXIMAL_RADIUS:
+InertiaExpression3.jpg
+We can then use the Subject Data Metric X that we just created in another expression. Enter the following expression into the Segment Properties Axial edit box:
+<code>
+(1+2*X+3*X^2)/4/(1+X+X^2)*RTH_SEG_LENGTH
+</code>
+InertiaExpression4.jpg
+Note: the edit box doesn't show the entire expression, which is a nuisance