From 28 nm technology node and below optical proximity correction (OPC) needs to take into account light scattering effects from prior layers when bottom anti-reflective coating (BARC) is not used, which is typical for ionic implantation layers. These effects are complex, especially when multiple sub layers have to be considered: for instance active and poly structures need to be accounted for.A new model form has been developed to address this wafer topography during model calibration called the wafer 3D+ or W3D+ model. This model can then be used in verification (using Tachyon LMC) and during model based OPC to increase the accuracy of mask correction and verification. This paper discusses an exploration of this new model results using extended wafer measurements (including SEM). Current results show good accuracy on various representative structures.