The present invention relates to pliable capacitive structures such as dielectric elastomers and similar smart materials which can be used for sensing externally applied strains which can be inferred by the determining the capacitance of the structure/material. There is provided an apparatus comprising a pliable capacitive structure for use in detecting shape or strain changes, the pliable capacitive structure having a dielectric material positioned between two electrodes; means for applying a steady-state voltage across the two electrodes; and means for determining changes in capacitance of the pliable capacitive structure using said steady state voltage.