  Riptide is a detector concept aiming to track fast neutrons. It is based on
neutron--proton elastic collisions inside a plastic scintillator, where the
neutron momentum can be measured by imaging the scintillation light. More
specifically, by stereoscopically imaging the recoil proton tracks, the
proposed apparatus provides neutron spectrometry capability and enable the
online analysis of the specific energy loss along the track. In principle, the
spatial and topological event reconstruction enables particle discrimination,
which is a crucial property for neutron detectors. In this contribution, we
report the advances on the Riptide detector concept. In particular, we have
developed a Geant4 optical simulation to demonstrate the possibility of
reconstructing with sufficient precision the tracks and the vertices of neutron
interactions inside a plastic scintillator. To realistically model the optics
of the scintillation detector, mono-energetic protons were generated inside a
$6\times6\times6$ cm$^3$ cubic BC-408 scintillator, and the produced optical
photons were propagated and then recorded on a scoring plane corresponding to
the surfaces of the cube. The photons were then transported through an optical
system to a $2\times2$ cm$^2$ photo sensitive area with 1 Megapixel. Moreover,
we have developed two different analysis procedures to reconstruct 3D tracks:
one based on data fitting and one on Principal Component Analysis. The main
results of this study will be presented with a particular focus on the role of
the optical system and the attainable spatial and energy resolution.
