Daylighting has an important influence in two of the main consumption sources of a building: whereas solar gain makes a great influence on the consumption of the heating and cooling systems, solar illuminance can reduce the use of artificial light and its electrical equipment. Whatever the final objective, lighting analysis of indoor rooms implies the knowledge not only of its location and orientation toward the North, but also of the location, dimensions and geometry of its main entrances of natural light, commonly windows and glass exterior doors. In this paper, as-built 3D models are proposed for their use as input in lightning analysis given their adequacy for providing information about the geometry and the semantics of the building. Furthermore, a methodology for their generation is presented, taking as a basis the geometric information of the reality of the building, acquired only with a laser scanning device.