Joins two face selections rigidly: the follower faces move exactly with the driver faces. Only points of faces B within the radius are tied; if none are, the block reports an error. Between two bodies treated as solid the faces are tied where the bodies touch, in the analysis' cells both reach; a gap wider than a cell is not bridged, and the analysis says so by name.
Faces on the first (independent) side.
Faces on the second (dependent) side, tied to faces A near them.
Also tie rotations. Not supported yet: leave off.
Search distance in mm (default 1). Points of faces B farther than this from the driver faces are not tied.