peer reviewed ; Since the financial crisis of 2008, architecture must face growing conditions of instability. This rekindles the necessity to integrate the parameter of uncertainty into architectural design much like the concerns developed by the radical architects of the 1960s. At that time, these architects associated with megastructures challenged the opposites: fix/transient, permanent/ephemeral, primary/secondary structure, indeterminate/determinate. They raised the questions of uncertainty, instability over time, and gave shape to this condition. Their predecessors inside Team X introduced concepts like the ‘aesthetics of change’ (Smithsons), the ‘open form’ (Hansen), ‘open aesthetic’ (Voelcker) and developed architectural theories regarding indeterminacy and fragmentation. Out of a synthesis of this theoretical background, we propose to withdraw a conceptual tool with which we review the approach of two contemporary architectural offices, particularly concerned by the question of indeterminacy, uncertainty, open aesthetics and open structure in their achievements. Doing so, we aim to provide insights of what can constitutes a legacy out of megastrucuralist theory and identifies conceptual shifts.