Extreme ultraviolet lithography (EUVL) uses a 13.5nm exposure wavelength, all-reflective projection optics, and a reflective mask under an oblique illumination with a chief ray angle of about 6 degrees to print device patterns. This imaging configuration leads to many challenges related to 3D mask topography. In order to accurately predict and correct these problems, it is important to use a 3D mask model in full-chip EUVL applications such as optical proximity correction (OPC) and verifications. In this work, a fast approximate 3D mask model developed previously for full-chip deep ultraviolet (DUV) applications is extended and greatly enhanced for EUV applications and its accuracy is evaluated against a rigorous 3D mask model.