Direct slicing from CAD models to generate sectional contours of thepart to be sintered for Selective Laser Sintering (SLS) may overcome inherent disadvantages of using a Stereo Lithography ( STL ) format. In this paper, a direct slicing procedure is proposed for Selective Laser Sintering based on material performance and process parameters. Slicing thickness depends on the 3 D geometric model,material performance and process parameters. The relationship among material performance, process parameters and the largest slicing thickness is established using analysis of a sintering temperature field. A dynamic linked library is developed to realize direct slicing from a CAD model.