DM
The DM function returns the magnitude of the translational displacement vector from marker j to marker i. Marker j defaults to the global coordinate system if it is not specified. DM is the distance between markers i and j and, by definition, is always non-negative.
Format
DM(i[,j])
Arguments
i | The marker whose origin is being measured. |
j | The marker whose origin is the reference point for the displacement calculation. |
Extended Definition
Mathematically, DM is calculated as follows:
where 
is the displacement of marker i in the global coordinate system and 
is the displacement of marker j in the global coordinate system.
is the displacement of marker i in the global coordinate system and is the displacement of marker j in the global coordinate system.Examples
SFORCE/1, I=21, J=11, TRANSLATION
, FUNCTION=-30*(DM(21,11)-25)**1.72
, FUNCTION=-30*(DM(21,11)-25)**1.72
This SFORCE statement defines a nonlinear spring whose free length is 25. The stiffness is 30 force units per unit deformation. DM(21,11)-25 represent the deformation in the spring. 1.72 is the exponent to which the deformation is raised.
See other Displacement measures available.