We propose a non-linear concurrent revision control for centralised management of 3D assets and a novel approach to mesh differencing. Large models are decomposed into individual scene graph (SG) nodes through an asset import library and become versioned as collections of polymorphic documents in a NoSQL database (DB). Well-known operations such as 2- and 3-way diff and merging are supported via a custom DB front-end. By not relying on the knowledge of user edits, we make sure our system works with a range of editing software. We demonstrate the feasibility of our proposal on concurrent 3D editing and conflict resolution.