Estimate Construction Costs from Revit/IFC Models with GPT-4 and Claude

Estimate material price and total cost for grouped BIM/CAD elements using an LLM-driven analysis. The workflow accepts an existing XLSX (from your model) or, if missing, can trigger a local RvtExporter.exe to generate one. It enriches each element group with quantities, pricing, confidence, and produces a multi-sheet Excel report plus a polished HTML executive report.

What it does - Reads grouped element data (from XLSX or extracted via RvtExporter.exe). - Builds enhanced prompts with clear rules (volumes/areas are already aggregated per group). - Calls your selected LLM (OpenAI/Anthropic/etc.) to identify materials, pick the pricing unit, and estimate price per unit and total cost. - Parses AI output, adds per-group KPIs (cost %, rank), and aggregates project totals (by material, by category). - Exports a multi-sheet XLSX and an HTML executive report (charts, KPIs, top groups).

Prerequisites - LLM credentials for your chosen provider (e.g., OpenAI, Anthropic). Enable exactly one chat node and connect credentials. - Windows host only if you want to auto-extract from .rvt/.ifc via RvtExporter.exe. If you already have an XLSX, Windows is not required. - Optional: Internet access on the LLM side for price lookups (model/tooling dependent).

How to use 1. Import this JSON into n8n. 2. Open the Setup node(s) and set: - projectfile — path to your .rvt/.ifc or to an existing grouped rvt.xlsx - pathtoconverter — C:\\DDCConverterRevit\\datadrivenlibs\\RvtExporter.exe (optional) - country — used to guide price sources/standards (e.g., Germany) 3. In the canvas, enable one LLM node (e.g., OpenAI or Anthropic) and connect credentials; keep others disabled. 4. Execute workflow (Manual Trigger). It will detect/build the XLSX, run analysis, then write the Excel and open the HTML report.

Outputs - Excel: PriceEstimationReportYYYY-MM-DD.xlsx with sheets: - Summary, Detailed Elements, Material Summary, Top 10 Groups - HTML: executive report with charts (project totals, top materials, top groups). - Per-group fields include: Material (EU/DE/US), Quantity & Unit, Price per Unit (EUR), Total Cost (EUR), Assumptions, Confidence.

Notes & tips - Quantities in the input are already aggregated per group — do not multiply by element count. - If you prefer XLSX-only extraction, run your converter with a -no-collada flag upstream. - Keep ASCII-safe paths and ensure write permissions to the output folder.

Categories Data Extraction · Files & Storage · ETL · CAD/BIM · Cost Estimation

Tags cad-bim, price-estimation, cost, revit, ifc, xlsx, html-report, llm, materials, qto