Most damage prediction models for reinforcing steel in concrete treat the corrosion propagation stage as an independent module, with little dependence on the prior history of corrosion development in nearby portions of the structure. A next generation interdependent model (IM) addresses those interactions for chloride-induced corrosion. The model incorporates the corrosion prevention effect of the local potential drop caused by prior active-to-passive transitions in nearby steel portions. Prior work demonstrated IM for 1D and 2D configurations but 3D realizations were needed. An exploratory 3D approach is presented here, toward incorporation in practical modeling forecasts. Confirming previous 1D and 2D models, the long-term damage projected for the 3D IM was only a fraction of that forecast using traditional potentialindependent threshold modeling. A computational scheme using intermediate regular point grids was created to enable and speed up calculations. Issues requiring further development are identified.