massing

Open, self-hosted, IFC-native AEC platform: web BIM viewer + modeling, a ~100-module GC portal (RFIs, pay apps, CPM, construction accounting — double-entry GL/WIP → QuickBooks, e-sign), AI assist, IDS authoring, estimating + embodied carbon, a development proforma, and operate/dispose (CMMS, facility condition, rent roll, waterfall). Maintained by ibuilder on GitHub, where it has earned 123 stars from the community.

It's actively developed around bim, construction, ifc, and is a solid reference for anyone building with these tools.