The precise computation of NURBS-based geometries using isogeometric analysis (IGA) has become increasingly accessible through specialised software and tools. Large-format additively manufactured components, due to their shell-like and thin-walled nature, are particularly well-suited for such methods. In current practice, however, design, structural analysis, and manufacturability verification are typically handled in separate tools, limiting iterative, performance-driven design workflows. This work presents a parametric design-to-manufacturing workflow demonstrated on different examples including a 3D-printed balustrade developed in Grasshopper. Additive manufacturing constraints are integrated directly into the design and structural assessment phase, resulting in a continuous process chain from parametric modelling through structural design and optimisation to manufacturing-ready geometry. The approach enables parametric control of layer or strand width based on the local stress state, allowing increased material deposition in highly loaded regions and reduced deposition elsewhere within process limits. For large-format additive manufacturing, this leads to significant reductions in material usage, production time, and cost. A key contribution lies in the automated, geometry-driven definition of couplings in multipatch shell models. NURBS surfaces are interpreted as shell parts with parametrically varying thickness, and couplings between non-coincident patches are detected based on spatial proximity and thickness-dependent interaction zones rather than direct surface contact. This enables robust structural analysis of complex shell assemblies commonly encountered in additively manufactured components.