1. A computer system comprising: computer storage for storing an unordered group of images obtained from photographs taken at a site; and a processor connected with the storage and configured to meld together the unordered group of images such as to reconstruct dense three-dimensional (3D) and four-dimensional (4D) as-built point cloud models (“as-built models”) comprising merged pixels from the unordered group of images over time, where time is a fourth dimension added to the three dimensions of the site captured from the group of images.