A method of creating a 3-D model of a body part , the body part being coupled to an orthopedic fixator , the orthopedic fixator comprising at least four markers at predetermined scalar distances along the orthopedic fixator, the method comprising: receiving a first roentgenogram of the body part and the orthopedic fixator disposed between an x-ray source and an x-ray imager in a first orientation , wherein the first roentgenogram includes an image of: the body part, the orthopedic fixator, and the at least four markers; receiving a second roentgenogram of the body part and the orthopedic fixator disposed between the x-ray source and the x-ray imager in a second orientation , wherein the second roentgenogram includes an image of: the body part, the orthopedic fixator, and the at least four markers; determining a first set of projections of the at least four markers on the first roentgenogram; determining a first 3-D position of the x-ray source and a first 3-D position of the orthopedic fixator with respect to the x-ray imager in the first orientation using the predetermined scalar distances between the at least four markers and the first set of the projections of the at least four markers on the first roentgenogram; determining a second set of projections of the at least four markers on the second roentgenogram; determining a second 3-D position of the x-ray source and a second 3-D position of the orthopedic fixator with respect to the x-ray imager in the second orientation using the predetermined scalar distances between the at least four markers and the second set of projections of the at least four markers on the second roentgenogram; aligning the first and second 3-D orthopedic fixator projections in a 3-D reference frame using the 3-D positions of the at least four markers with respect to the x-ray imager in the first and second orientations; and creating a 3-D model of the imaged body part in the 3-D reference frame based on the first and second 3-D orthopedic fixator projections. receiving a first roentgenogram of the body part and the orthopedic fixator disposed between an x-ray source and an x-ray imager in a first orientation , wherein the first roentgenogram includes an image of: the body part, the orthopedic fixator, and the at least four markers; the body part, the orthopedic fixator, and the at least four markers; receiving a second roentgenogram of the body part and the orthopedic fixator disposed between the x-ray source and the x-ray imager in a second orientation , wherein the second roentgenogram includes an image of: the body part, the orthopedic fixator, and the at least four markers; the body part, the orthopedic fixator, and the at least four markers; determining a first set of projections of the at least four markers on the first roentgenogram; determining a first 3-D position of the x-ray source and a first 3-D position of the orthopedic fixator with respect to the x-ray imager in the first orientation using the predetermined scalar distances between the at least four markers and the first set of the projections of the at least four markers on the first roentgenogram; determining a second set of projections of the at least four markers on the second roentgenogram; determining a second 3-D position of the x-ray source and a second 3-D position of the orthopedic fixator with respect to the x-ray imager in the second orientation using the predetermined scalar distances between the at least four markers and the second set of projections of the at least four markers on the second roentgenogram; aligning the first and second 3-D orthopedic fixator projections in a 3-D reference frame using the 3-D positions of the at least four markers with respect to the x-ray imager in the first and second orientations; and creating a 3-D model of the imaged body part in the 3-D reference frame based on the first and second 3-D orthopedic fixator projections. <EOS>