Extent of the bottom boundary of the extrapolation volume (white contours; a rectangle in CEA coordinates) compared with selected full-disk observations before (first and second columns) and during the filament eruption (third column). The pre-eruption SDO/HMI LOS magnetogram and the SDO/AIA 211 Å and 304 Å images, match the time of our NLFFF extrapolation (19:34 UT). The KSO Hα image was recorded at 14:59 UT.