Modeling an object in 3-D space may be accomplished various embodiments disclosed herein. An exemplary method of creating a 3-D model includes receiving roentgenograms of an object and at least one reference marker. In some embodiments, the roentgenograms may each include an image of at least one object marker. The exemplary method may further include determining 3-D positions of the x-ray source using the images of the at least one reference marker. The location of the 3-D positions of the x-ray source may allow a 3-D model of the imaged object to be created.