||For a same project, engineers tend to use different software to perform different tasks such as geometry modeling, database management, numerical analysis and data visualization. This may cause decrease of productivity and losses of information during the conversion process between different data file formats. In, most lighting analysis tools for example, the geometry modeling and pre-processing features does not provide all the capabilities available in a CAD (Computer Aided Design) system. Also the presentation of numerical results does not allows a rich and interactive data exploration/visualization such as is provided by Scientific Visualization tools and Virtual Reality systems. The aim of this paper is to describe an lighting analysis application which is an add-in for a 3-D CAD system which integrate all CAD modeling features, algorithms for mesh generation, numerical processing and post-processing of scalar fields, management tools for fixtures database, and a VRML (Virtual Reality Modeling Language) writer/exporter. Basically the application use the workspace of the CAD system as a 3-D interface for to plan the lighting scheme (luminaires choice and positioning), to process the illumination in 2D or 3D meshes chosen by the user, and then, to visualize and explore the results through scalar field scientific visualization techniques (p.e. contours, cut, slices, color mapping). Therefore, the application developed consist of a lighting analysis tool which integrate features for pre-processing, processing and visualization of illuminance fields with rich and intuitive visual interactivity. The method used for the algorithms developments are described and two examples of application are presented, a power substation and a simple house lighting plan.