Filmed in September/October 2009 at the third Columbia Conference on architecture, engineering and materials. Few concepts are as central in structural engineering as the ability of a material to sustain plastic deformation under tensile stress. The standardization of historically known deformation limits or ductile properties in most materials allows architects and engineers to keep the analysis of structure within known parameters of finite element analysis rather than materials science. If the material behavior is known, the statics equations for its organization are predictable. If the new material is new or the organization is unique, naturally, the risk is less clear, but it is rare for architects and engineers in practice to encounter new material performance quotients. If the goal is to avoid fracture, the boundaries are set and the limits of ductility are observed. Post ductility refers to the literal aspects of material behavior -- in the case of metals -- but also to aspects of architectural and urban space that are measured by less verifiable but nonetheless real quotients of stress. These include both aspects of plasticity that are common to architectural discourse for centuries such as concepts of the plastic arts, and also literally up to-the minute entities such as sprawling cities that exceed historic limits of plastic or formal coherence. In both cases it is the reciprocity of tension and compression of space that provides form or gives coherence to form. What does ductility mean today if you seek material or spatial limits; how do you measure limits and to what degree do historically stable measurements of ductility still enable spatial organizations in architecture, in engineering or in cites? Are there spatial innovations in new materials; have we changed the limits of known materials leaving architecture to find its significance in other realms?