1. A computer-implemented method, comprising: receiving input identifying features in one or more images of a three-dimensional (3D) physical object, the identified features effective to define one or more surfaces for the 3D physical object, and said surfaces that are defined forming an existing object model; selectively displaying said surfaces of the existing object model of the 3D physical object at a current viewing direction to reduce a number of surfaces displayed at the current viewing direction, said selectively displaying comprising: determining a normal vector for a given surface included in the existing object model; determining an angle between the normal vector of the given surface and the current viewing direction of the existing object model; and determining whether the angle between the normal vector and the current viewing direction is greater than a threshold value, and: displaying the existing object model without the given surface if the angle is greater than the threshold value; or displaying the existing object model with the given surface if the angle between the normal vector and the current viewing direction is less than the threshold value.