These Attributes establish a Cartesian coordinate system relative to the Frame of Reference of the implant. When two implants are assembled using a pair of mating features, a rigid spatial registration can be established, that transforms one Frame of Reference so that the mating features align.
Mating Feature Degree of Freedom Sequence (0068,6400) is used to specify that a mating feature allows mating with another implant not only in one defined pose, but within a certain range of freedom. One sequence item specifies one degree of freedom that may be a rotation around or a translation along an arbitrary axis. The Degree of Freedom Type (0068,6420) specifies whether the degree of freedom describes a rotation or a translation.
The 3D coordinates of the axis of translation or rotation is specified by 3D Degree Of Freedom Axis (0068,6490) with respect to the Implant Template’s Frame of Reference as three-dimensional vector in x-y-z order. Range Of Freedom (0068,64A0) specifies an interval, in millimeters or degrees, by which this 3D coordinate system mating feature may be moved along or around the axis.
For each HPGL Document, the 2D Degree Of Freedom Axis (0068,64F0) may be specified as a 3D vector encoded in x-y-z order, where the z-coordinate is equal to the direction of projection, i.e., equal to the cross product of the x- and y-axis of the printing space. Range Of Freedom (0068,64A0) specifies an interval, in millimeters or degrees, by which the 3D coordinate system of this mating feature may be moved along or around the axis.