A system includes a balloon catheter having a shaft, an inflatable balloon fitted at a distal end of the shaft, and multiple electrodes disposed on the inflatable balloon, a display, and a processor configured to receive signals that are indicative of respective electrode positions of the multiple electrodes in 3D space, compute the respective electrode positions of the multiple electrodes based on the received signals, from among a plurality of virtual planes defined by different respective groups of the electrode positions, select a virtual plane that contains a maximum number of the electrode positions to within a given tolerance, fit a virtual circle to the electrode positions that are within the given tolerance of the selected virtual plane, and render to the display a 3D representation of the balloon catheter based on a position and orientation of the fitted virtual circle in 3D space.
