Architectural engineering education can adopt the Conceive-Design-Implement-Operate (CDIO) framework as a linear representation of design–engineering processes. However, renovation projects are inherently iterative and constraint-driven, challenging linear interpretations of CDIO. While iteration is acknowledged conceptually within the CDIO literature, empirical studies that make such process patterns visible in educational practice, particularly in renovation-oriented architectural engineering, remain limited. This paper addresses this gap by examining how CDIO is enacted in practice within a renovation-focused architectural engineering studio through a combined analysis of task-level process data and experiential indicators. Empirical material consists of task-sequence data from 19 students, yielding 207 CDIO-aligned transitions derived from course submissions, together with 226 task-based survey records capturing perceived Purpose, Control, Effort, Persistence, Enjoyment, and Groupmate contribution. Course-native task categories were mapped to CDIO stages, with Operate interpreted as a representational and integrative phase enacted through final posters and presentations. Process behavior was analyzed using Sankey-style visualizations and explicit identification of backward CDIO transitions as loops. Results indicate that CDIO progression is predominantly directional but explicitly non-linear. Within-stage iteration accounted for 56.5% of transitions, forward transitions for 30.4%, and backward transitions for 13.0%. Backward transitions were concentrated primarily in the Implement stage, reflecting reframing triggered by technical resolution, representational demands, and constructability constraints. Remarkably, backward transitions were also observed from Operate, indicating that final presentations occasionally prompted reconsideration of earlier design or implementation decisions rather than functioning exclusively as terminal stages. Experiential results show consistently high perceived collaboration and goal orientation across tasks, with moderate-to-high levels of Grit and Vision. Vision was strongly associated with Purpose and Enjoyment, while Grit was closely related to Effort and Persistence.
