The Local Link Reference Frame ( LLRF ) is a Cartesian coordinate system rigidly attached to the link. Every link specific information is defined with respect to this coordinate system.
The $LDLinkGroundTransformation record is recalculated, when PlaceLinkage function is called.
The $LDLinkGroundTransformation record is optional. If it is not present the transformation matrices are calculated on the fly.
In case of reasonable number of parameter of the linkage ( < 20 ) the pre-calculated $LDLinkGroundTransformation speed up the calculation of the animation frames.