This report details the development of a 2D and 3D Method of Characteristic (MOC) tool for the design of complex nozzle geometries. These tools are GUI driven and can be run on most Windows-based platforms. The report provides a user's manual for these tools as well as explains the mathematical algorithms used in the MOC solutions.Rice, TharenGlenn Research CenterNOZZLE GEOMETRY; THREE DIMENSIONAL MODELS; NOZZLE DESIGN; SUPERSONIC COMBUSTION RAMJET ENGINES; METHODOLOGY; GRAPHICAL USER INTERFACE; ALGORITHMS; CONTOURS; WALL PRESSURE; MACH NUMBER...