Massing — in-browser BIM authoring · construction docs · GC portal · proforma

Open, self-hosted, IFC-native AEC platform. A genuine in-browser BIM authoring tool — model from scratch (blank or a template) and draw/drag-edit real IFC by GUID across architecture · structure · MEP, generate a permit-ready construction-document set (plans, sections, elevations, schedules → SVG/PDF/DXF, issuable ARCH-D sheets, a 3-part MasterFormat spec manual), pre-check code (IBC occupancy/egress, jurisdiction-adopted editions, an approvability pre-flight), and hand over field-verified as-built data (LOD-500 + manufacturer/serial, COBie-ready). Plus a near-100-module GC portal (RFIs, pay apps, CPM schedule, TRIR) and a development proforma — one model, from land acquisition through operations. Generate a building from a zoning envelope, or model it by hand; then coordinate, schedule, underwrite & operate it. Built on That Open + IfcOpenShell. $0 to run.

Making the most powerful thing in AEC feel like the simplest.

Breadth is the asset; it is also the risk. 47% of contractors name getting people to use new technology their single biggest challenge — ahead of cost or integration (AGC, 2024) — and 12% of features carry 80% of daily use across 615 measured subscriptions (Pendo, 2019). So the design rule is defer, never delete: route each person to the ten things they touch today, keep the rest one keystroke away. See the design audit & interface plan and the R24 interface ring in the roadmap.

What it is — three pillars on one IFC-keyed model, reached through seven rooms — Deal · Design · Planning · Schedule · Cost · Work · Operate — that stay in the same place for every role:

• 🧊 BIM platform — a genuine in-browser authoring tool on That Open Fragments, from a blank model to a permit-ready set: draw/edit walls (incl. sloped-top parapet/shed/gable), columns, slabs, doors/windows, curtain walls, steel connections, rebar cages and MEP (with port-to-port connectivity) by GUID-stable server-side recipe, with drag-to-move edit-in-place, model undo/redo, automatic drawing inference (auto on-axis/parallel/perpendicular snap), a family/type system, groups/arrays, phasing, LOD dialing (100→500), a site content library (logistics/furniture/landscaping, auto-classified), a procedural-mesh and an AST-sandboxed ifcopenshell escape hatch (feature-flagged), authoring guardrails that reject broken IFC, and an a CAD command line (AutoCAD-style WALL 0,0 5,0 3 / COLUMN 2,2 with aliases, history and spacebar-repeat) alongside an AI command bar (type what to build in plain English); generate the construction-document set — plans/sections/elevations/schedules → SVG · PDF · DXF, issuable ARCH-D sheets with titleblocks, and a 3-part MasterFormat project manual; code intelligence — IBC code-analysis (G-series) summary, edition-aware occupancy-load + egress pre-check, jurisdiction-adopted code editions, an approvability pre-flight, a detail-rule engine, and a decision-readiness (RFI-prevention) audit; plus a productivity-rate labour estimate, QA, IDS, BCF, PDF takeoff (calibrated measure / area / count); layer & align multiple models with federated cross-discipline clash; raise 2D → BIM (DXF floor plan → IFC walls + spaces) and check the built result with scan-to-BIM deviation (as-built point cloud vs the model surface, % within tolerance + heatmap); also opens meshes & point clouds (OBJ/STL/PLY/glTF · PCD/XYZ/LAS/LAZ) and GIS / topography (GeoJSON vectors · GeoTIFF DEM terrain) as georeferenced reference overlays, with QR sharing
• 🏗 GC portal — config-driven modules: RFIs, submittals, change orders, pay apps (G702/G703), CPM schedule, safety/TRIR, closeout (COBie); specification register → spec-driven submittal log (AI/rules extraction of typed submittals from the spec book, with missing-submittal coverage); contract & change-order documents (AIA-style generate · Exhibit A scope · redline · per-party + PAdES digital e-sign); Report Center (executive / cost / EVM / logs → PDF + Excel)
• 💵 Development proforma — sources & uses, S-curve draws, XIRR/NPV, JV waterfall — seeded straight from the model

▶ Live demo · ⬇ Download (Win/macOS/Linux) · 📚 Guides · 📄 Project page

Quickstart — self-host the full stack

docker compose --profile full up --build      # web → http://localhost:8080 · api → http://localhost:8000
docker compose --profile full --profile seed run --rm seed   # optional: a demo project across every module

Or install the signed desktop app (single-project, auto-updating) from the latest release.

Built on That Open (Fragments + web-ifc, MIT) · IfcOpenShell (LGPL) · three.js · FastAPI · Tauri. IFC is the source of truth — no proprietary format, no per-seat license.

The whole lifecycle, on one model

Most AEC software covers a single slice — feasibility, or BIM, or construction management. This platform spans the whole lifecycle on one IFC-keyed model: acquisition → due diligence & entitlements → feasibility → design → preconstruction → construction → turnover → operations (CMMS, metered energy, reserves/CIP, CAM, ESG/POE), with every artifact (proforma, model, RFI, pay app, COBie, work order, meter reading) tied to the same GlobalIds.

• Pre-acquisition — due-diligence studies (Phase I ESA, geotech, title…) + entitlement pipeline with a go/no-go readiness rollup.
• Feasibility + underwriting — proforma, sources & uses, investment memo.
• Concept programming — spaces as an adjacency graph (area × quantity → gross area + use mix that feeds the massing generator).
• Generative massing + test fit — zoning envelope → buildable program → real IFC building.
• openBIM standards (ISO 19650) — a Common Data Environment (WIP → Shared → Published → Archived), information-requirements register (EIR/BEP/AIR), model-quality scoring (IDS compliance, LOIN, export health, bSDD), a 10-category BIM-KPI scorecard, and standards-compliance checks.
• BIM authoring + coordination — from-scratch in-browser modeling (blank/template start, Draft toolkit, drag-to-move edit-in-place, manage levels, model browser with group-by/search, selection sets), clash detection, IDS validation.
• openBIM data depth (Wave 9) — property mapping / normalization (remap vendor psets onto an IDS/employer structure, the transform between validation and export); IFC5-style property-override layers (non-destructive composition with conflict detection + bake); a semantic model graph (multi-hop, cited IFC-relationship queries); computed code pre-check (occupancy load + egress capacity, IBC-cited); generative fit-out (auto-furnish spaces); and site logistics on the 4D timeline (schedule-windowed cranes/laydown/gates).
• AI over the model — an MCP server so external agents (Claude Desktop) can drive the project: read status/records, run schedule-risk, carbon, permit-readiness, drawing-QA and standards checks, and author the model with GUID-stable recipes — all through the same gated engines the UI uses, with a drop-in Claude skill pack (docs/mcp-skills/). Offline-first; nothing fabricated.
• Construction management — RFIs, submittals, change orders, pay apps, 4D/5D.
• Turnover — COBie, as-built, closeout, certified substantial completion (G704).
• Operations — CMMS work orders + preventive maintenance, utility meters → EUI, reserve study + capital plan, facility condition assessment (UNIFORMAT II elements → Facility Condition Index + portfolio prioritization, feeding the reserve forecast), CAM reconciliation, ESG rollup (GHG Scope 1/2) + post-occupancy evaluation.
• Climate & water resilience — flood risk (ASCE 24 / FEMA Design Flood Elevation + a flood-proof-MEP check flagging equipment installed below it), stormwater sizing (Rational Method Q = C·i·A peak runoff + detention volume), weather-sequenced construction (weather-sensitive activities + a site-weather-hazard register + weather-delay days from the daily reports), and a physical climate-risk rating that rolls up into the ESG scorecard — rainfall and flooding as quantifiable parameters across the lifecycle.
• IFC-native, open, self-hostable — no per-seat license; the desktop app is free.

What it does

Highlights, all built and verified in this repo unless noted:

• Web viewer — Three.js + Fragments, streams large models, runs fully offline (local WASM).
• Navigation & review — select→properties, spatial tree, layers, isolate/hide, ghost, section planes, measure, color-by-data, set-origin/CRS.
• Coordination — model federation; clash detection (AABB broad phase + mesh boolean narrow phase, exact penetration volume) → BCF clash topics.
• Issues — BCF-modeled topics/RFIs/punch/clash, viewpoints, comments, attachments, pins; .bcfzip import/export (round-trips with any BCF-compatible openBIM tool).
• QA — IDS validation (ifctester) with failing-element highlighting.
• 4D / 5D — schedule↔element mapping; quantity takeoff + cost mapping (geometry fallback).
• Data export — QTO, COBie, space schedules → XLSX.
• 2D documentation — dimensioned grid plans (grid derived from columns), sections, elevations (N/S/E/W) with level lines, and composed PDF sheets with title blocks.
• Authoring round-trip (in-browser modeling) — a full toolkit of authoring ops, each a server-side ifcopenshell recipe → background republish (reconvert + reindex). GUID-stable, so pins/RFIs/clashes survive. Start: a blank model (levels + ground datum) or a starter template (office bay / residential floor / warehouse). Create: walls (incl. sloped-top — parapet-slope / shed / gable), slabs, columns, beams, roofs, rooms/spaces (sketch on the model/grid); parametric doors/windows (real lining/frame/panel) that void the host wall + fill it. Free-hand drawing lands clean lines automatically via automatic axis inference (auto on-axis / parallel / perpendicular snap within ~6°, no Shift needed). Fabrication / LOD 350-400 (behind an "Advanced" toggle): curtain-wall systems (mullions/transoms + glazing), structural steel connections (base plates, shear tabs + bolts as IfcElementAssembly), rebar cages (longitudinal bars + stirrups), MEP fittings (elbows/tees/transitions with ports + distribution systems) with port-to-port connectivity (IfcRelConnectsPorts + a dangling-element report), a procedural mesh (author an element from a raw triangle mesh → IfcTriangulatedFaceSet), and an AST-sandboxed ifcopenshell escape hatch (off by default, feature-flagged) for geometry the recipes can't express. Site content: a content library places logistics (cranes / hoists / fencing / sanitary units / laydown), furniture and landscaping, each auto-classified into the right IFC class + phase (logistics time-phase on the 4D slider) + Uniclass/OmniClass. Edit: drag-to-move edit-in-place (transform gizmo + ghost preview) with full model undo/redo (every edit is versioned, GUID-stable), plus typed delete / move / rotate / copy / per-element Pset edit, groups & arrays, and phasing (new / existing / demolish / temporary). Organize: a power-selection query (the IfcOpenShell selector DSL — by class, material, pset value) saved as reusable selection sets; LOD dialing (tag elements 100→500 on a view-keyed representation spine). Levels: rename + set-elevation. Browse: model tree grouped by level / discipline / class / type with search. Drafting aids: grid + corner snap, a 6-face section box, a storey-levels overlay. Reliability: authoring guardrails (guards.py::precheck) reject broken edits (zero-length walls, non-finite coordinates, bad dimensions) before they touch the model. AI command bar: type an instruction ("a 5×4 m room at 0,0", "steel column W14×30 at 6,6") — a deterministic keyword baseline works with zero setup, and an optional Claude multi-step planner turns one instruction into a validated, confirm-before-apply plan (it never invents GUIDs; every step re-validates through the same guardrail). Verified live end-to-end (new model → draw → edit-in-place → clash → export). Desktop GUI authoring is the optional Blender + Bonsai bridge.
• Construction-document set (author → issuable sheet) — generate a permit set straight from the authored geometry (deterministic, from extruded-profile footprints — no geometry kernel): plans (class-styled poché, dimensions, keynote bubbles + legend from the model's spec codes, and NCS-style detail callouts — a divided circle + leader on every element carrying an attached detail, with a keyed DETAILS legend), auto-centred sections (X-X / Y-Y) and projected elevations (N/S/E/W), and computed door / window / room schedules — each as SVG, laid out on an issuable ARCH-D (36×24″) sheet with a border + titleblock, and exported to PDF (via reportlab) and DXF (a dependency-free R12 writer for CAD interchange). Plus a 3-part MasterFormat project manual — the model's elements grouped into CSI divisions → sections in SectionFormat shape (Part 1 General / Part 2 Products / Part 3 Execution) from their work-result classifications + attached detail documents. A detail-rule engine (IDS-shaped condition → content) auto-attaches keynotes, spec codes and installation details — e.g. a window in an exterior wall gets the IBC/ASTM/AAMA flashing detail + MasterFormat/UniFormat codes — and validates as author-time QA.
• Code intelligence (pre-check, cites sections) — a permit set's G-series IBC code-analysis summary computed from the model (occupancy classification, construction type, area + story count, the computed occupant load + egress, governing allowable-area/height + fire-rating sections); an occupancy-load + egress pre-check (per-space load, required vs provided egress width, 32-in door + two-exits-over-49 checks) whose occupant-load factors are edition-aware — a jurisdiction on an older IBC cycle (e.g. Business at 100 gross ft²/occ in 2012/2015 vs 150 in 2018+) computes a higher load and egress width than the current baseline; a jurisdiction-adopted-edition catalog (codes.py — the I-Code families + their 3-year editions, resolved per US state) so citations name the edition in force ("IBC 2021 Table 506.2 …"); an approvability pre-flight — a plan-reviewer readiness checklist (egress capacity, door clear width, two-exits, occupancy classification on spaces, substantiated rated assemblies) scored for permit-readiness; and a decision-readiness (RFI-prevention) audit — the proactive inverse of the RFI, composing failed code checks, elements missing a required detail/keynote, model-hygiene gaps (orphaned / unenclosed / unnamed / duplicate) and open clashes into one ranked resolve-before-issue list (category + severity + fix), isolating each flagged element in 3D. A pre-check assist that cites sections — not a certified review; verify with the AHJ.
• LOD-500 / turnover (field-verified as-built) — stamp elements field-verified as-built (Massing_AsBuilt: Status + VerifiedBy/Date/Method/Note provenance) with a readiness rollup by method (field-measure / laser-scan / total-station / photo / submittal / inspection); stamp field-verified as-built dimensions (Massing_AsBuiltDim: measured value, design value, the variance, and a within-tolerance flag — measured-vs-design capture, with an out-of-tolerance count); stamp manufacturer/serial data (Pset_ManufacturerTypeInformation + Pset_ManufacturerOccurrence) that round-trips to COBie and CMMS/asset systems; and a composite Model Health scorecard across five lenses — integrity, ISO-19650 information, clash coordination, verified-as-built, and Code & permit-readiness (from the approvability pre-flight).
• Generative design — zoning → a fully-developed IFC building + proforma — enter a municipal zoning envelope (lot, FAR, coverage, setbacks, height limit, floor-to-floor) and the platform computes the buildable program (footprint, floors, GFA, units, binding constraint) and generates a real IFC4 model in one call — optionally with a concrete structural frame (columns + beams on a bay grid), per-apartment unit layout, a facade envelope (walls + ribbon windows at a WWR, feeding the energy model), and a service core (elevator + stair + MEP risers) — then publishes it and solves a starter acquisition proforma. Because the output is openBIM, the generated building flows straight into the viewer, drawings, energy, QTO, the assembly-based estimate (+ GFA benchmark) and underwriting — one chain from lot → deal → turnover. Driven end-to-end through a full lifecycle harness (63/63).
• Furnish & equip (starter IFC family library) — a curated 16-family catalog (furniture / sanitary / appliances / plants) generated parametrically, placeable into any model (incl. a generated massing) as real, GUID-stable, typed IFC occurrences via type.assign_type.
• Sign-in (SSO) + free tier, no admin — log in with Google / Microsoft / Procore (OAuth2); SSO users are plain free-tier accounts and there's no admin tier for end users (project owners manage their own teams; platform config is ops/env). A tier seam (entitlements.py) makes the eventual paid plans a one-place change.
• First-run onboarding + AI assistant — a skippable welcome + coach-mark tour for new users, and an "Ask AI" box that answers natural-language questions about a project (open RFIs, overdue, cost) grounded in a live snapshot (Claude when keyed; graceful no-key fallback).
• Field/mobile capture (offline-first) — a mobile bottom-sheet quick-capture: snap a photo → punchlist / safety observation / progress photo in a couple taps. Captures queue offline (photo included) and auto-sync on reconnect (queued-count badge); pairs with the PWA/Capacitor build.
• Turnover — a one-click closeout package (/closeout/package.zip: as-built IFC + COBie/QTO/spaces + status PDF + closeout manifest), module-log PDFs (RFI/submittal/CO registers), multi-period pay apps (period advance + auto lien waivers), COBie tabs enriched with warranties/assets/commissioning, and warranty-expiry tracking.

General Contracting Portal

A construction-management portal on top of the viewer — full writeup in docs/gc-portal.md. Highlights:

• Module engine — every process (RFIs, Submittals, PCO/Change-Order chain, Daily Reports, …) is a module.json → its own auto-created table. 133 modules / 30 sections, no per-module code. Each gets CRUD, role-gated workflow, comments, CSV/PDF, pins, timeline.
• Two role dimensions — capability roles (viewer→admin) + party roles (GC/Owner/OwnersRep/Consultant/Subcontractor) that gate workflow transitions.
• Change-order chain — PCO ▸ NOC ▸ Directive ▸ Proposal ▸ COR ▸ eTicket, linked and audit-logged; approved CORs flow into the contract sum.
• Financials — AIA G702/G703 pay apps (+ PDF), Cost Summary roll-up, eTicket T&M builder priced from rate tables, and a WIP schedule (percentage-of-completion) whose physical progress can be cross-checked against the model — installed elements ÷ total by IFC GlobalId, flagging cost running ahead of what's actually built.
• Schedule — Gantt + Empire-State Line-of-Balance charts.
• Role-tailored dashboard — per-party KPIs + "ball-in-your-court" action items.
• Model pins — any anchored record (RFI/PCO/COR/punchlist/inspection/…) shows on the 3D model; clicking selects the element and opens the record. Same GUID keys geometry, BCF, and GC records.

Real-Estate Development & Feasibility (Finance workspace)

A developer/owner platform that goes lot → building → deal → investor package, all IFC-native.

Generative design & Test Fit (openBIM — every fit is a real IFC model):

• Generate from zoning — lot + zoning envelope (FAR, setbacks, height, coverage) → a buildable program + a from-scratch IFC4 model (structural frame, per-unit spaces, facade + windows, service core) + a solved acquisition proforma, one click. Real lot polygons (shoelace area).
• Test Fit — fit a unit mix on a double-loaded corridor (real units + corridor), a parking solver (stalls/unit → count/area/cost), scheme compare (units/efficiency/NSF/parking ranked), and generative optimize that sweeps unit-mix × parking and ranks by yield-on-cost ("find the deal that pencils"). POST /test-fit/{compare,optimize}.

Developer cost portal — the institutional underwriting facets:

• Line-item hard/soft cost budgets (description × $/unit × qty + per-category contingency) that roll into the proforma cost tree.
• Sources & Uses — grouped uses vs sized senior debt (LTC capped by LTV/DSCR/debt-yield) + equity.
• Property & tax assumptions — parcel/areas/purchase + tax table → OPEX; per-SF ratios.
• Specialty assets — on-site energy (solar/wind/battery/rainwater → capex + energy offset) and vertical-farm/PFAL (tower count → produce revenue + lighting opex), flowing into the deal.
• Investment memo (PDF) — a confidential memorandum (exec summary, S&U, cost budget, returns, risk) generated from live project data: the "presentation with financials."

Underwriting engine:

• Sources & uses with construction-loan interest-reserve circularity solved to a fixed point.
• S-curve draws, XIRR / NPV / equity multiple / yield-on-cost, a JV waterfall (pref + promote tiers, American/European, clawback), debt sizing (LTC/LTV/DSCR/debt-yield), sensitivity tables and Monte Carlo risk.
• Underwriting realism — specialty/operating revenue is risk-adjusted (not booked as de-risked rent), and guardrails flag returns outside market bands (IRR / equity-multiple / dev-spread / DSCR) so the IRR is credible, surfaced on a sticky returns bar.
• Actuals/draws bridge → re-forecast IRR + AIA G702/G703 pay apps off the same cost tree.
• Multi-deal portfolio roll-up (true XIRR) and LP-shared read-only scenarios.

The Finance workspace is organized into sub-tabs — Feasibility · Budget & Capital · Underwriting · Deliverables — with a sticky live-solved returns bar.

Architecture

            IFC  (source of truth)
   author ▲                       │ convert + tile
          │                       ▼
  Blender + Bonsai         services/converter (Node)   IFC → .frag tiles
  (Bonsai-MCP)                    │
  services/data (Python, ifcopenshell)                 props index · QTO/COBie/4D/5D ·
    clash · IDS · drawings/sheets · authoring recipes   exports · validation · 2D drawings
          │                       │
          └──────► services/api (FastAPI) ◄──────► apps/web (Vite + TS, Three.js + Fragments)
             BCF issues · pins · viewpoints · properties · exports · clash · validate ·
             drawings/sheets · edit/publish      (Postgres/SQLite + MinIO/local storage)

Four constraints hold this together: elements are referenced by IFC GlobalId and never by a viewer id; IFC is pre-converted to Fragments server-side and never parsed in the browser at runtime; geometry and metadata stay separate; and the viewer runs fully offline.

Full detail — the repo layout, where each kind of work runs, the canonical "spines" to reuse rather than rebuild, and the tests that hold each claim in place — is in docs/reference/architecture.md.

Install

git clone https://github.com/ibuilder/massing.git && cd massing
cp .env.example .env            # set secrets + AEC_RBAC=1 for anything but local dev
docker compose --profile full up --build      # web → http://localhost:8080  (api → :8000)

# optional: fill a demo project across all relation chains
docker compose --profile full --profile seed run --rm seed

The web container reverse-proxies /api to the API (same-origin, no CORS), serves the viewer with the cross-origin isolation web-ifc needs, and persists Postgres/MinIO/IFC volumes. .env.example documents every knob.

Prefer not to run a stack? Install the signed desktop app (single-project, auto-updating, free) from the latest release.

Building from source needs Node 24 and Python 3.12 — Node 18 does not build the web app. The dev setup, the first-project walkthrough and the test commands are all in docs/getting-started.md.

Running it in production? Deployment → go-live checklist → operator runbook.

Documentation

📚 docs/ is the index. The paths people usually want:

Install and first project	getting-started.md
Learn to use it	User guide — the seven rooms, authoring, drawings, records, files
See it demoed	walkthrough.md
Something is broken	troubleshooting.md
Call the API	reference/api.md, or /docs on a running instance
How it is built	reference/architecture.md
Add a record type	authoring-modules.md — no code required
What is planned	roadmap.md · release history · CHANGELOG

API surface

66 routers. The live, authoritative reference is /docs on any running instance — FastAPI generates it from the code, so it cannot go stale. For the grouped map of what exists, see docs/reference/api.md.

A taste of the shape:

POST   /projects/{id}/edit | /publish          authoring round-trip (GUID-stable recipes)
POST   /projects/{id}/generate/massing         zoning → IFC massing + acquisition proforma
GET    /projects/{id}/drawings/sheet.pdf       issuable ARCH-D sheet
POST   /projects/{id}/cost/estimate → /sov     price the model, then build the SOV from that estimate
GET    /projects/{id}/codecheck/occupancy      edition-aware occupancy + egress, IBC-cited
GET/POST /projects/{id}/modules/{key}          any of 133 registers, config-driven CRUD

Verification

Every feature here was run against the sample model. The latest end-to-end proof: IDS flagged 299 slabs missing LoadBearing → the authoring round-trip edited them → republish → IDS re-validated PASS (299/299) with the slab's pin GUID unchanged. Regressions: web tsc, API smoke test, and Python compile all green.

Licensing

Open stack (That Open MIT-style, IfcOpenShell LGPL). The Blender + Bonsai desktop editor is GPL — kept a separate process you use, not linked in. Optional Autodesk APS RVT→IFC is paid/flagged. See LICENSE-NOTES.md.

Author

Created by Matthew M. Emma — built with Claude Code as AI assistant.