[en] The work we present consists of the development of a computerised 3-D scanning system running under LABVIEW[reg]. 3-D magnetic field measurements, form an important application allowing a fast on-line determination of charged particle trajectories in real magnetic fields. The set-up consists of a Hall-probe, movable in three dimensions, mimicking a charged particle entering a magnetic field with well-defined transport characteristics (energy, position, momentum). The measured local field components are used as input to a LABVIEW[reg] program, which calculates the local direction of the flight-path of the particle. Then the probe is moved along this direction with a predetermined step-length. In this way, the real path of the charged particle is determined step by step automatically accounting for all magnetic field imperfections. Trajectories can be determined without the measurement of the whole 3-D field configuration