Diffuse view factors (or form factors) between two planar polygonal surfaces placed at arbitrary orientation relative to each other serve as inputs for surface-to-surface radiation transport or other similar calculations. In this article, a general formulation and accompanying numerical procedures are presented to perform such calculations. The formulation uses a parametric vector representation of the two surfaces along with the well-known contour integral method to develop an integral formula that finally requires a numerical quadrature scheme to evaluate. The use of the parametric vector representation of the surfaces overcomes the difficulty of defining limits to the integrals in the contour integral method. Six test cases are considered, and the results are compared either to exact analytical solutions (when available) or to Monte Carlo results, which are also generated as part of this study. It is found that irrespective of the case studied, the present method matches analytical results perfectly (up to six decimal places accuracy) with a 10-point or higher Gaussian quadrature scheme. The errors in the Monte Carlo results increase when the two surfaces are either far from each other and/or at grazing angles, although the actual errors are quite small (less than 0.5%). For the cases when analytical solutions are not available, the Monte Carlo results and those generated by the present method were found to be in close agreement. (C) 2012 Elsevier Ltd. All rights reserved.