With an increased reliance on modeling and simulation in the defense community a requirement has developed for improved ground target infrared signature prediction capabilities. Predictive ground target infrared signature modeling has traditionally been done using the Physically Reasonable Infrared Signature Model (PRISM). The PRISM code has been used extensively in support of signature management for vehicle designers as well as other applications. The intended replacement for PRISM, the Multi-Service Electro-optic Signature (MuSES) code, has recently been developed and offers increased capabilities and ease of use. Until recently, IR/thermal signature analysis suffered from a disparity between the geometry required to predict signatures and the geometry used to design vehicles. The solution to the IR geometry problem was the development of MuSES, which uses meshed CAD geometry. MuSES is a rapid prototyping thermal design tool and an infrared signature prediction tool. To restore modularity lost over ten years of PRISM evolution, a new object-oriented thermal solver was created. The solver incorporates numerous advanced features including a net enclosure method for radiation, CFD interface, restart/seed capability, batch mode, and alternate solution strategies (such as the partial direct solution method). The MuSES interface is optimized for engineers/analysts who need to incorporate signature management treatments or heat management solutions into vehicle designs. Topics covered by this paper include a detailed description of the MuSES code and its capabilities, as well as multiple examples of model creation. The geometry modeling paradigm for the MuSES code represents a radical shift in how a vehicle model is created for the purpose of infrared signature modeling. The model creation examples are presented to demonstrate the tools and techniques used as well as to convey lessons learned to potential users in proper geometry modeling and meshing techniques.