CITA Complex Modelling investigates the infrastructures of architectural design models. By questioning the tools for integrating information across the expanded digital design chain, the book asks how to support feedback between different scales of design engagement moving from material design, across design, simulation and analysis to specification and fabrication. The book conveys the findings of the Complex Modelling research project a five-year framing project supported by the Independent Research Fund Denmark. Undertaken at CITA, the Centre for Information Technology and Architecture, The Royal Danish Academy of Fine Arts, School of Architecture, Complex Modelling asks how new interdisciplinary methods for adaptive parametrisation, advanced simulation, machine learning and robotic fabrication can be orchestrated within novel workflows that expand the agency of architecture.