A new lightning shielding failure evaluation method based on the electro-geometric method aided by 3D graphics technology is introduced. The approach is based on the collection surface method. Shielding devices and protected equipment are equally considered as targets of lightning strikes when generating collection surfaces. The collection surfaces are then projected to a 2D bitmap, identified by colors to represent protected and unprotected areas respectively. An integral is performed on the amplitude of the stroke current (weighted by the probability distribution of this amplitude) to account for the dependency of the shape and size of the unprotected surface on the stroke current. By using the collection surfaces of equipment instead of the unprotected area, empty areas where no equipment is to be protected are eliminated from contributing to the failure analysis. The technique applies to structures or substations of any shape, and can use different striking distances to horizontal and vertical objects. The example 69 kV substation described in IEEE Standard 998 is used to demonstrate the usage of this technique. (C) 2015 Elsevier B.V. All rights reserved.