The Hybrid Manufacturing is the blend of subtractive and additive manufacturing processes. Additive manufacturing processes have seen nowadays as an upward trend in complex and structurally sound industrial applications. At the same time, there is still an open ground in modeling and simulation techniques when applied to these processes. There are many fabrication processes in modern manufacturing, but current modeling and simulation tools only simulate a few unit processes based on different geometry models. To overcome the problem between different models, this paper studies various in-process geometry models together with their working systems for traditional manufacturing processes. Novel hybrid 5 axis multiple machining, 5 axis laser cladding, and layered manufacturing processes are presented to identify critical issues. Working towards a vision of pervasive modeling and simulation, a unified deformable in-process geometry model and simulation for 5 axis multiple machining, 5 axis laser cladding, and layered manufacturing simulations is developed and discussed.