Conversion of streamlines from trk to tck

Revisiting this because i’ve recently had an issue with data conversion.

I’ve been running the same tck -> trk conversion for years, which uses nipype’s mrtrix interface ( essentially ) :

import nipype.interfaces.mrtrix as mrt
import shutil

tck2trk = mrt.MRTrix2TrackVis()
tck2trk.inputs.image_file = b0file
tck2trk.inputs.in_file = os.path.join(os.path.dirname(infile), '%s.tck' % tckname)
tck2trk.run()
shutil.move('converted.trk',os.path.join(os.path.dirname(infile), '%s.trk' % tckname))

Currently, the output data no longer lines up in trackvis ( L = trackvis, R = mrview )

I believe this started when i upgraded mrtrix3 from RC1 -> RC2. I’ve also tried it on RC3 with the same results. Any ideas whats going on? Has mrtrix3 changed the way it stores things in headers of the data that could attribute to this? Its nice to be able to use trackvis for easy filtering by lengths, ROIs, etc