1. A computer-implemented method for modifying a three-dimensional model using a set of two-dimensional photographic images, comprising: (a) receiving at least one constraint, input by a user, for a two-dimensional photographic image from the set of two-dimensional photographic images, each constraint indicating that a position on the two-dimensional photographic image corresponds to a position on the three-dimensional model; (b) when the number of constraints received in (a) for the two-dimensional photographic image is less than or equal to a first threshold value, locking camera parameters representing a camera that took the photographic image constrained in (a); and (c) applying a photogrammetry algorithm to at least the set of parameters to determine at least one unlocked parameter in the set of parameters and to modify the three-dimensional model based on the constraint in (a), wherein the set of parameters comprises camera parameters that include, for respective cameras that took the two-dimensional photographic images, a position of the camera when the camera took the photographic image, an orientation of the camera when the camera took the photographic image, and a focal length of the camera, whereby locking the camera parameters enables efficient execution of the photogrammetry algorithm.