Unit vector along X (UVX)
The UVX measure returns the unit vector in the direction of the x axis of marker i, resolved in the coordinate system of marker k.
Format
UVX(i[,k])
Arguments
Applied To Marker (i) | The marker whose x-axis unit vector is being measured. |
Reference Frame (k) | The marker in whose coordinate system the unit vector is being expressed. If k is not specified, k defaults to the global coordinate system. |
Extended Definition
Mathematically, UVX is calculated as:
where:
■
is the unit vector along the x-axis of marker i.
is the unit vector along the x-axis of marker i.■
is the unit vector along the x-axis of marker k.
is the unit vector along the x-axis of marker k.■
is the unit vector along the y-axis of marker k.
is the unit vector along the y-axis of marker k.■
is the unit vector along the z-axis of marker k.
is the unit vector along the z-axis of marker k.Examples
VARIABLE/1, FUN=DXYZ(i,j)*UVX(k)
VARIABLE/2, FUN=DX(i,j,k)
Variables 1 and 2 are synonymous. They both produce the translational displacement between markers i and j along the direction of the x-axis of marker k.