Models of the spray forming process from different groups show reasonable agreement with each other and with the real process. Use of these models has provided considerable insight into the several complex processes involved in spray forming; in addition, the models allow designed experiments to provide further insight into the process. In the work described it has been shown that the modeled fraction of liquid in the spray f j (s) appears to be an appropriate control parameter for spray forming. Sticking efficiency and porosity have been found to correlate well with f j(S) . The differences found in the optimum value of the fraction of liquid in the spray for billets (0.3) and tubes(0.5-0.6) indicate, however, that the actual control parameter may be the fraction liquid in the deposit, f j (d) on the surface under the spray. The need for improved modeling, particularly of the full thermal profiles in complex geometries such as spray deposited tubes, is discussed as is the value of improved process diagnostic tools for direct experimental measurement of such features as droplet sizes and velocities, and the deposit temperatures in actual spray forming processes.