Filament boxing option of Ximdisp. The user sets the box width before selecting each end of each candidate filament. Box corners are stored in a file which can be read by a separate program for calculating box centres with a user set inter-box distance. The box centres are stored in a file which can be read directly into RELION for processing. The illustration shows HsRad51 complexed with single-stranded DNA (EMD-8183; Short et al., 2016).