  We present a method to include stereoscopic information about the three
dimensional structure of flux tubes into the reconstruction of the coronal
magnetic field. Due to the low plasma beta in the corona we can assume a force
free magnetic field, with the current density parallel to the magnetic field
lines. Here we use linear force free fields for simplicity. The method uses the
line of sight magnetic field on the photosphere as observational input. The
value of $\alpha$ is determined iteratively by comparing the reconstructed
magnetic field with the observed structures. The final configuration is the
optimal linear force solution constrained by both the photospheric magnetogram
and the observed plasma structures. As an example we apply our method to SOHO
MDI/EIT data of an active region. In the future it is planned to apply the
method to analyse data from the SECCHI instrument aboard the STEREO mission.
