Agree it's a big effort, so approaching as open as we can to attract cooperation. We also have a new company that has taken seed funding. I'm a systems engineer/data scientist, working with architects and 3d folks who know the state of the art well.

The architecture will tend towards platform + apps, to help address the scale problem. We're looking to partner/port the geometry kernel and focus on workflow and integration with open standards (IFC,STEP,gltf,Collada).

Initial UI is in react+three.js (soon react-three-fiber) with git for file-based versioning underneath. Also interested in recent discussions on HN about CRDTs on Matrix for collaboration. So kind of a CRDT real-time google docs capability on top of a persistent file based rep on git. This part is very fun coding :)

Just getting started! Appreciate any feedback, esp on our github/discord :)