Disclosed are a method, system and apparatus for analyzing foam decomposition in gap mode during mold filling in lost foam casting, the casting process in gap mode characterized by a bubble flux and the mold filling having a mold filling speed. The method includes providing a plurality of values for casting process parameters as variables in a plurality of predetermined equations, simultaneously solving the plurality of predetermined equations including the parameter values, calculating a flux value for the bubble flux, a gap value for the gap width, and a speed value for the mold filling speed, and determining whether to adjust at least one of the parameter values based on at least one result for the bubble flux, mold filling speed, or gap width.