Contech Takeoff

AI and 3D takeoffs

My September 2026 workflow combines Python extraction, Three.js, and GLB exports to connect drawings, model geometry, and quantities. Read how the workflow works and the morning that changed how I think about takeoffs.

What it does

Pull up satellite imagery for any site. Drop a PDF or image plan set on top, georeferenced to the satellite. Trace lines, polygons, and points to measure the work. Attach a thickness and a material to any polygon and get instant length, area, cubic yards, and tons of asphalt, concrete, dirt, base, etc.

Effectively a Google Earth front end with the takeoff math (Agtek / Trimble Business Center / PlanSwift territory) baked in. 3D earthwork (cut/fill from elevation) is on the roadmap, not in v0.1.

v0.1 features

• Satellite map with pan, zoom, address search, scale bar.
• Draw tools: point (count), line (length), polygon (area), rectangle (area).
• Auto totals: length (LF), area (SF / AC), count (EA).
• Per-polygon thickness in inches → volume in CY.
• Material catalog: HMA, concrete, CABC, crushed stone, topsoil, common fill, sand, riprap. Density and swell/shrink applied automatically.
• CY → tons via density, with a loose vs compacted toggle for earthwork.
• Plan overlay: load a PDF or image, click two known points on the plan and the matching two on the satellite to align.
• Save / load: projects persist to browser storage, exportable as JSON.

The math

CY    = area_sf * (thickness_in / 12) / 27
Tons  = CY * density_lbs_per_cf * 27 / 2000
loose_CY     = compacted_CY * (1 + swell)
compacted_CY = bank_CY * (1 - shrink)

All material defaults are editable per item. Density and swell/shrink defaults live in data/materials.json.

Roadmap

• v0.2: CSV export, dollar-cost layer (rate × qty), print summary, multi-project dashboard.
• v0.3: 3-point georeferencing, regional material spec packs, per-item density override.
• v0.4: 3D terrain via Cesium + USGS 3DEP elevation data → real cut/fill volumes and mass haul.
• v1.0: User accounts, cloud sync, integrations with the Contech Estimator and Edgevanta bid intelligence.

Notes

• Imagery is Esri World Imagery (free for non-commercial, attribution shown). For production, swap in Mapbox satellite or a paid Esri tier.
• 2-point alignment handles translate + rotate + uniform scale. Plans with skew or non-uniform horizontal/vertical scale will need the v0.3 3-point upgrade.
• Browser storage is capped around 5 MB. Large overlay PDFs are kept in memory only and need to be re-attached when reopening a saved project.