Digital simulation which was introduced to the architectural field due to the rapid growth of computer graphics, gave birth to a new type of contents called 'virtual reality', led by the interaction with the users and real time processing. The public attention is drawn to the virtual reality's potential as a next generational space simulation it, having the unique characteristics of 'simulation', 'interactivity', 'tole-presence', and 'immersion', is capable of taking a virtual tour of a space with a size equivalent to that of a real space, as well as proceeding with the design progress. Nonetheless, many problems impeding CPU's real time processing of an excessively loaded architectural model data have been pinpointed over the time. Yet such GPU based game engines as 'DirectX' and 'OpenGL', developed to deal with these impediments, have not been easily applied to the architectural simulation in the design process, due to the high license cost and the specific technical requirements for the system. The virtual reality has been developed and distributed centering around the gaming field, and game developers recently show a greater tendency to include level editors in the package for the expandability purpose. Thus, we plan to propose architecture simulation which utilizes level editors in this study. In addition, the compatibility of the game engine based level editors of Quake and Unreal which form the standards for the open source FPS games, based on VRML, the standard format for the virtual reality, was compared and analyzed. Taking the example of Villa Savoye of Le Corbusier, its application possibility as an architecture simulation was assessed, by measuring the extent to which the performance of such characteristic features of the virtual reality as interactivity, immersion, and tele-presence, was improved.