1. A computer implemented method of determining a view impact of a target structure, the method comprising: loading a 3D scene; determining a view point and direction of interest of said loaded 3D scene; rendering, without the target structure, a plane of said loaded 3D scene image perpendicular to said determined view point and direction of interest at a distance from said view point distal of the target structure; counting the number of pixels for said rendered plane without the target structure; rendering, with the target structure, a plane of said loaded 3D scene image perpendicular to said determined view point and direction of interest at the distance from said view point distal of the target structure; counting the number of pixels for said rendered plane with the target structure; and calculating the difference between the counted pixels with the target structure and the counted pixels without the target structure.