(TPT) [@tpt2; @tpt_erice; @tpt_ex] which indicate how to twist the dynamics of a given system to calculate the reaction rate between a given reactant and product state. The method proposed in this note can be seen as a generalization to arbitrary nonequilibrium processes at statistical steady state of the milestoning procedure with Voronoi tessellation proposed in Ref.  by building upon the original works in Refs. . This generalization makes the procedure more expensive computationally, but it permits to relax completely the assumptions made in milestoning – these assumptions were discussed in detail in Ref. . Our method can also be viewed as a generalization of the transition interface sampling (TIS) [@tis2; @pptis; @tis3] and forward flux sampling (FFS) [@ffs; @valerianiFFS] methods in which arbitrary sets of interfaces can be used that do not have to be placed in monotone succession.

The remainder of this note is organized as follows. First we revisit from an original perspective the nonequilibrium sampling procedure of Refs. . Next, we show how this procedure can be modified to calculate reaction rates exactly using TPT. We then compare our procedure with the Markovian milestoning method proposed in Ref.  and with TIS [@tis2; @pptis; @tis3] and FFS 