Many researchers have focused on thermal, structural or other multiphysics modeling of laser and electron beam powder bed processes. However, in most cases, the laser heat source distribution is considered Gaussian as an ideal beam. However, power intensity distribution is a function of many parameters that need to be considered if realistic modeling of laser interaction with surface is desired. This work seeks to model the process in a more comprehensive and realistic manner by taking the laser physics into consideration including the wavelength, laser quality factor and laser beam parameter product. The model also uses a level set method to determine the shape of the bead and melt pool during melting and solidification process. Other physics including the heat transfer and fluid flow is incorporated in the simulation to model the whole process. This multiphysics process is used to model the melt pool geometry. Results are compared against an experiment for Inconel 718 alloy.