Rebar Cutting & Bending Optimization API

A REST API that takes a bar bending schedule (BBS) plus your available stock and returns an optimized cutting plan, bending schedule and offcut inventory — deterministic, machine-readable, ready to embed in your ERP, estimating or detailing software.

Built on the CutOptim engine — 1,259 published benchmark jobs →

The problem

Rebar fabricators cut thousands of bars a day from 12 m stock. The cutting plan is made by hand, in Excel, or inside closed desktop suites. Every rebar ERP and detailing tool needs waste optimization — but today there is no rebar-aware developer API for it: generic cutting APIs know nothing about shape codes, bending deductions or machine formats, and rebar suites keep their optimizers locked inside desktop products.

Published case studies report 0.9–1.5% waste on optimized plans; one fabricator trial halved its scrap.

Sources: rebar cutting-waste optimization in BIM (Buildings, MDPI, 2025) · GoSmarter / Midland Steel field trial

What the API does

Input: bar list (mark, Ø, grade, BS 8666:2020 shape code, dimensions, qty) plus a stock definition (standard lengths and reusable offcuts) and options (cut allowance, minimum reusable offcut).

Output: per Ø/grade cutting patterns (which stock bar becomes which cuts), waste %, the offcuts produced, and a bending schedule with cut lengths and weights.

How it works

Example

Illustrative — the exact contract is being finalized with design partners.

POST /v1/rebar/optimize
{
  "units": "mm",
  "stock": {
    "standardLengths": [12000, 6000],
    "offcuts": [{ "diameter": 16, "length": 3400, "qty": 12 }]
  },
  "options": { "cutAllowance": 5, "minReusableOffcut": 1000 },
  "bars": [
    { "mark": "B01", "diameter": 16, "grade": "B500B",
      "shapeCode": "11", "dimensions": { "A": 2000, "B": 350 }, "qty": 140 },
    { "mark": "B02", "diameter": 16, "grade": "B500B",
      "shapeCode": "00", "length": 4750, "qty": 60 }
  ]
}

{
  "engineVersion": "rebar-1.0.0+e7c2",
  "summary": { "stockBarsUsed": 49, "wastePct": 1.7,
               "totalWeightKg": 958.3, "offcutsProduced": 6 },
  "cutPlans": [{ "diameter": 16, "stockLength": 12000, "patterns": [
    { "count": 21, "cuts": ["B01","B01","B01"], "wasteMm": 465 },
    { "count": 14, "cuts": ["B02","B02","B01"], "wasteMm": 158 }
  ] }],
  "bendingSchedule": [
    { "mark": "B01", "cutLength": 2302, "qty": 140 },
    { "mark": "B02", "cutLength": 4750, "qty": 60 }
  ],
  "offcuts": [{ "length": 1420, "qty": 4 }]
}

Cut lengths are computed from the shape code and dimensions with standard bending deductions (e.g. shape 11: A + B − 0.5r − d), or you can supply your own cut lengths and use pure cutting optimization.

Built on a proven engine

This is not a from-scratch project — it takes the CutOptim engine (already sold as a developer API, with 1,259 public benchmark jobs) into a new domain, adding the shape-code, bend-deduction and offcut-inventory layer on top of a 1D optimizer that already works.

Results are deterministic and version-pinned: the same input and the same engineVersion always produce the same output — so an optimization is auditable and reproducible inside quotes and production orders.

Who it is for

Software teams that already own the rebar workflow and want optimization without building a solver:

• Rebar ERP / MES and fabrication-management software
• Estimating & CPQ tools that quote reinforcement by weight and waste
• Detailing add-ins (Tekla, Revit, Allplan) that already produce a BBS
• Precast concrete production software
• CNC / bending-machine software that needs an optimized cut list

On the roadmap

Deliberately not in v1 — built with a customer, not on speculation:

• BVBS (.abs, BF2D/BF3D) export for bending machines; Unitechnik/PXML for precast
• IFC / Tekla BBS import
• Coil/spiral processing and multi-strand shear-line constraints
• PDF bending-schedule documents