An automatic method of categorizing the contact force of a catheter tip against a portion of a patient's heart based on motion of the catheter tip, the method comprising (a) capturing a series of 3D-coordinate data points of the catheter tip as a function of discrete times with a 3D medical imaging system, the 3D coordinates corresponding to an orthogonal 3-axis spatial coordinate system, (b) using a programmable computing system, computing a set of measures based on the series of 3D-coordinate data points, (c) categorizing each measure by a respective set of predetermined threshold values; and (d) combining the categorized measures to yield a relative quality of the contact force.