Large, multinational software development organizations face a number of issues in supporting software design and modeling by geographically distributed architects. To address these issues, we present CoDesign, an extensible, collaborative, event-based software modeling framework developed in a distributed, collaborative setting by our two organizations. CoDesign’s core capabilities include real-time model synchronization between geographically distributed architects, as well as detection and resolution of a range of modeling conflicts via several off-the-shelf conflict detection engines.