YoArrowFX3D example

Let's create a new force vector for the right foot. Start by clicking Add...:

In the new dialog, select Arrow in the 3D Graphics section and name it "Right foot force":

Click Create. A new editor becomes available on the right side while a new blue arrow appears in the 3D view:

Note the presence of a check mark for most fields. This helps identifying whether a field is properly filled or not, in which case the check mark becomes . A new YoGraphic cannot be saved until all check marks are green.

Let's link the origin of the arrow to the point of application for the force on the right foot. In the Search Origin look for "DesiredExternalWrenchr_footPointOfApplication" and press Enter, the editor should be updated as follows:

Note that the arrow updated its origin in the 3D view to match the position referred by the YoVariables. Also note that the coordinates of the arrow's origin can also be set individually.

Let's do the same for the arrow's direction. Look for "DesiredExternalWrenchr_footForce":

Now the arrow updated its direction and, in this example, is now hidden inside Atlas' shin.

Let's modify the size properties of the arrow as follows:

By selecting the scale option for the length, the length of the arrow is now set to be proportional to the magnitude of "DesiredExternalWrenchr_footForce", i.e. in this example the length of the arrow is now proportional to the magnitude of the force applied on the right foot, the field Body length and Head length becomes multipliers.

After saving this new YoGraphic, the arrow in the 3D view tracks the force for the right foot: