A method of operating an interferometric system to use multiple shape-sensing optical cores (A, B, C, D) and a single optical core in a fiber housing to generate a three-dimensional data set for at least a portion of an anatomical target based on distance measurements of multiple points of the target from a distal end of the fiber housing and measurements of respective three-dimensional positions and pointing directions of the distal end, the multiple shape-sensing optical cores (A, B, C, D) located alongside the single optical core, the method comprising: (a) projecting, over a first range of multiple frequencies, collimated light from the single optical core to a current point of a target while the distal end of the fiber housing is directed toward the current point; (b) using optical frequency domain reflectometry to detect reflected light scattered from the current point and to process the reflected light to determine a distance of the distal end to the current point; (c) projecting, over a second range of multiple frequencies, light through the multiple shape-sensing optical cores (A, B, C, D) to the distal end of the fiber housing; (d) using optical frequency domain reflectometry to obtain a measurement of light reflected from the distal end of the fiber housing back through the multiple shape-sensing optical cores (A, B, C, D) and to process the measurement of light reflected to determine a position in three-dimensional space of the distal end of the fiber housing and a pointing direction of the distal end of the fiber housing; (e) using the determined position in three-dimensional space of the distal end of the fiber housing, the pointing direction of the distal end of the fiber housing, and the determined distance to determine a position in three-dimensional space of the current point; and repeating (a)-(e) multiple times for multiple additional current points of the target to generate the three-dimensional data set for at least the portion of the target, wherein, to generate the three-dimensional data set, the single optical core is used to determine distances of the distal end to the multiple points of the target, and wherein generating the three-dimensional data set requires combining the distances with the respective three-dimensional positions and pointing directions of the distal end. (a) projecting, over a first range of multiple frequencies, collimated light from the single optical core to a current point of a target while the distal end of the fiber housing is directed toward the current point; (b) using optical frequency domain reflectometry to detect reflected light scattered from the current point and to process the reflected light to determine a distance of the distal end to the current point; (c) projecting, over a second range of multiple frequencies, light through the multiple shape-sensing optical cores (A, B, C, D) to the distal end of the fiber housing; (d) using optical frequency domain reflectometry to obtain a measurement of light reflected from the distal end of the fiber housing back through the multiple shape-sensing optical cores (A, B, C, D) and to process the measurement of light reflected to determine a position in three-dimensional space of the distal end of the fiber housing and a pointing direction of the distal end of the fiber housing; (e) using the determined position in three-dimensional space of the distal end of the fiber housing, the pointing direction of the distal end of the fiber housing, and the determined distance to determine a position in three-dimensional space of the current point; and repeating (a)-(e) multiple times for multiple additional current points of the target to generate the three-dimensional data set for at least the portion of the target, wherein, to generate the three-dimensional data set, the single optical core is used to determine distances of the distal end to the multiple points of the target, and wherein generating the three-dimensional data set requires combining the distances with the respective three-dimensional positions and pointing directions of the distal end.