During an extrusion-based 3d printing process involving viscous-phase materials, whenever the nozzle-to-layer distance crosses a certain threshold value, the extruded thread snaps out from its linear configuration and starts to buckle in a variety of coiling and looping patterns. This nonlinear material behavior is known as Viscous Thread Instability. This project provides an initial applied research perspective on whether architecture- and construction-related digital workflows can leverage similar active and nonlinear material behaviors and, more specifically, whether these behaviors can be controlled and exploited for the production of graded architectural structures. The computational backbone of the research is a feedback-based pipeline linking a parametric design environment to a sensor-adaptive robotic additive fabrication setup which is able to produce customized Functionally Graded Structures.