An interactive user-friendly incremental calibration technique that provides immediate feedback to the user when aligning a point on a 3D model to a point on a 2D image. A can drag-and-drop points on a 3D model to points on a 2D image. As the user drags the correspondences, the application updates current estimates of where the camera would need to be to match the correspondences. The 2D and 3D images can be overlayed on each other and are sufficiently transparent for visual alignment. The user can fade between the 2D/3D views providing immediate feedback as to the improvements in alignment. The user can begin with a rough estimate of camera orientation and then progress to more granular parameters such as estimates for focal length, etc., to arrive at the desired alignment. While one parameter is adjustable, other parameters are fixed allowing for user adjustment of one parameter at a time.