This Letter reports a generalized theory of the smallest diameter of metallic nanorods from physical vapor deposition. The generalization incorporates the effects of nanorod separation and those of van der Waals interactions on geometrical shadowing. In contrast, the previous theory for idealized geometrical shadowing [Phys. Rev. Lett. 110, 136102 (2013)] does not include any dependence on nanorod separation and it predicts the diameter to be about to of what the generalized theory does. As verification, numerical solutions and the generalized theory in closed-form agree in terms of effective deposition flux. As validation, experiments of physical vapor deposition and the generalized theory agree in terms of the diameter as a function of the separation of nanorods.