  We present a unified derivation of Bohmian methods that serves as a common
starting point for the derivative propagation method (DPM), Bohmian mechanics
with complex action (BOMCA) and the zero-velocity complex action method
(ZEVCA). The unified derivation begins with the ansatz
$\psi=e^{\frac{iS}{\hbar}}$ where the action, $S$, is taken to be complex and
the quantum force is obtained by writing a hierarchy of equations of motion for
the phase partial derivatives. We demonstrate how different choices of the
trajectory velocity field yield different formulations such as DPM, BOMCA and
ZEVCA. The new derivation is used for two purposes. First, it serves as a
common basis for comparing the role of the quantum force in the DPM and BOMCA
formulations. Second, we use the new derivation to show that superposing the
contributions of real, crossing trajectories yields a nodal pattern essentially
identical to that of the exact quantum wavefunction. The latter result suggests
a promising new approach to deal with the challenging problem of nodes in
Bohmian mechanics.
