“…The integral in Equation (2) represents the net VOF advected out of the cell V F T and will be solved geometrically using the face-matched flux polyhedron advection (FMFPA-3D) method proposed in this work, which is described below. Before beginning the description of the proposed advection method, it should be mentioned that, before applying the advection step, the interface will be assumed to have been reconstructed in the previous time step using a PLIC method (such as that proposed in the companion paper [14]), in which the interface is reconstructed in each cell as a plane n·x+C = 0, where n points to the reference fluid. Since the aim of this paper is to assess the proposed advection method, widely used methods, for which many results are available in the literature, will be used to determine the vector normal to the interface, n, and constant C. Thus, unless otherwise stated, n will be obtained from the gradient of the volume fraction function, ∇F, using the method of Youngs [15] (see also [4,16]), and the constant C will be determined from the value of F in the cell and enforcement of local volume conservation using the analytical method of Scardovelli and Zaleski [17] (alternatively, an iterative method, such as Brent's method [18], could also be employed).…”