The U.S. Army Cold Regions Research and Engineering Laboratory (CRREL) is administering a multi-year, multi-agency infrared background data and modeling program entitled Smart Weapons Operability Enhancement (SWOE). This paper describes the progress made to date in model development and integration, under the direction of the Geophysics Directorate of the Air Force Phillips Laboratory. Other aspects of the program, not described here, include measurements and database development. A 1-D thermal model for natural backgrounds has been developed that covers a full range of background types. The range of types includes vegetated and nonvegetated surfaces, winter conditions, porous materials, and the presence of soil moisture. The model is also being used as a test bed for the development of a full 3-D model for natural backgrounds. The temperatures computed with this model are designed to be input to the radiometric models. Two models have been developed to compute the infrared radiances of natural background scenes, with both spectral and spatial capability. The first model computes radiances from terrain or water, while the second is used for modeling of discrete 3-D objects, such as trees, buildings, and vehicles. Both radiometric models includes thermal emission and reflections of the sun and sky. Atmospheric transmission and radiance are included. The terrain and objects may have spatially-varying temperatures and surface coatings. Emittances and reflectances are spectral and directional/bi- directional. Radiances computed with these models are translated to a Computer Image Generator (CIG) run by the U.S. Army Engineering Topographic Laboratory (ETL) for image rendering.