1. A method of estimating a fragment count for a display of at least one three-dimensional, 3D, object; the method comprising: determining an ellipsoid representative of a set of vertices defined by coordinates of the at least one 3D object; applying a transformation to the ellipsoid; calculating a projection area of the transformed ellipsoid; and estimating the fragment count for the display of the 3D object based at least partly on the calculated projection area of the transformed ellipsoid.