Public and common spaces in integrated mixed-use buildings in high-density urban environments increasingly take on the form of vertical extensions of public and common spaces on the ground level. Taken together, they can be understood as networks with multiple spatial programs, diverse land use, multi-occupancy, and circulation paths set in complex three-dimensional relationships. This paper argues that studying high-density vertically integrated buildings based on user-generated data can contribute to a better understanding of their socio-spatial performance. It presents aspects of an ongoing research project at the Singapore University of Technology and Design (SUTD) that uses a Complexity Science-based approach to study movement and space use in vertically integrated developments. The case study presented in this paper uses the SUTD Campus, an award-winning urban design and architectural project by Amsterdam, The Netherlands-based UN Studio and Singapore-based DP Architects as a case study. The project consolidates a typically laterally spread-out campus program  into a compact and vertically layered interconnected building complex. The paper presents a systematic post-occupancy socio-spatial study using the following methods: (1) qualitative architectural analysis, (2) quantitative spatial network analysis, (3) quantitative data collection, and (4) correlation analysis of actual performance with spatial network patterns. It discusses the use of infrared outdoor people counters, low-energy Bluetooth (BLE) devices, and smartphone sensors to map user movement. The collected data is subsequently analyzed to demonstrate how the public and common spaces within the integrated campus perform. The paper further explores the influence of the campus’ spatial layout on user behavior and movement patterns, and the impact on social interactions and user activities over time. The paper finally discusses the potential of this research methodology to inform the future planning and design of vertically integrated mixed-use developments.