Understanding Non-Functional Requirements (NFRs) and trade-offs among them is a key task for systems architects. Modeling notations have been proposed to represent NFRs and tradeoffs, among them, yet identification of relevant knowledge inside models (for understanding and/or reuse) remains quite simplistic and manual. This paper proposes to address fragment identification a problem best served with interactive aids and presents a faceted exploration approach to explore NFR solutions and identify reusable model fragments. NFRs and trade-offs are represented as ontologies, thus opening the door to model merging and high-end visualization. The approach is illustrated with a real-world model, and a prototype tool is introduced. The ultimate goal of this effort is enabling reuse of NFR and trade-off knowledge.