We study planar energy minimizing configurations of smectic A liquid crystal materials and classify the corresponding defect structures. We investigate focal conic configurations in wedge, non-parallel plates, funnel-shaped domains, and non-concentric annuli. The application of the stability condition for local conics is relevant to the specification of the location of the interfacial defects. Self-similar structures are discussed for a class of solutions with the same bulk energy. We propose surface energies terms to serve as selection mechanisms of particular self-similar configurations. We also show how the modelling of chevron texture naturally arises in the present framework.