A CFD method which combines convection, conduction and radiation heat transfer is presented. The working fluid is non-participating with respect to radiation, and hence the radiation, convection and conduction interact only at the fluid boundaries. The radiation is calculated using a modified form of the hemi-cube method on a radiation grid constructed from the structured fluids grid. The resulting software is flexible and adaptable to any geometry, with only a slight increase in computational effort compared with a non-radiative solution. Comparison with experimental data shows good solution accuracy in predicting boundary temperatures at radiation-convection boundaries.