The changing role of diagrams in architectural publications: From creative to communicative

Diagrams have long been central to architectural reasoning and communication. While their historical and conceptual roles are established, the impact of digitization on their function and representation is underexplored. This study systematically analyzes 245 diagrams from 45 architectural graphics publications between 1980-2025, classifying them by design stage, representation technique, production method, and purpose. The dataset analysis reveals a transformation in published diagrams: while 1980s-1990s diagrams were characterized by being manually produced, exploratory diagrams in early-stage design, the 2000s onward saw almost total digital production, yet representational conventions remained 2D. By the 2020s, diagrams shift toward external communication and coordination in later design stages, with conceptual and exploratory uses diminishing. The findings signal a cultural shift: diagrams in architectural literature now function less as cognitive tools and more as curated visual statements aimed at stakeholders. The study highlights the need for digital-native diagram practices and points to new ways of understanding their evolving role.