1. A method for generating a 3D model of a log having an axial center line, the method comprising: sensing the log with an X-ray imaging device; generating a densitometry measurement comprising densitometry data of the log; retrieving a 3D structure representative of the log and comprising a plurality of voxels each having a respective position therein, the voxels being shaped and sized to mimic a shape of at least a portion of a potential internal feature for the respective position; assigning a density value to each one of the voxels using the densitometry data, thereby generating the 3D model of the log; compensating for transverse motions from sensing of the log, outputting the 3D model, and further comprising displaying the 3D model, wherein the potential internal feature is an annular feature and/or a knot, wherein the knot extends outward from the axial center line of the log.