Technical Drawing Reader

What does Technical Drawing Reader do?

Technical Drawing Reader turns PDF or image drawings of machined parts into structured JSON. Upload a drawing (or paste a link) and get the data a quoting engineer or CNC shop types in by hand:

• Title block: drawing number, revision, title, part number, scale, sheet, projection method
• Material, with grade and condition split out (for example 42CrMo4+QT, EN AW-6082-T6)
• General tolerance (ISO 2768), normalised to ISO 2768-mK style
• Every toleranced dimension: deviations, ± tolerances, limit sizes and ISO 286 fits with the tolerance band computed in code (Ø20 H7 → +0.021 / 0)
• Threads: metric, UNC/UNF, trapezoidal, pipe. Includes pitch, class, depth, and internal or external
• GD&T feature control frames: characteristic, value, diametral zone, datums
• Surface roughness, including old N-grades converted to Ra
• Heat and surface treatments, edge requirements, notes
• Attention points for quoting: the tightest tolerance, the finest finish, fine-pitch threads, heat treatment and more, in plain sentences

It reads the drawing like a person would, using an AI vision model. It then checks the reading with deterministic engineering rules and adds warnings when something looks wrong.

Why use it?

• Faster quoting: see in seconds whether a part has a 0.013 mm band, a cylindricity of 0.005 or a hardened surface, before anyone opens the CAD model.
• Feed your systems: push drawing data into an ERP, MES, spreadsheet or RFQ tool via the Apify API, webhooks or integrations (Make, Zapier, n8n, Google Sheets).
• Bulk intake: run hundreds of supplier or customer drawings at once and filter them by material, tolerance or treatment.
• Fewer typos: tolerance bands come from the ISO 286 tables, not from the AI's arithmetic.

How to use it

1. Click Try for free. The input is prefilled with a sample drawing, so you can see the output right away.
2. Paste links to your drawings under Drawing links, or upload files under Upload drawings.
3. Optional: set Max sheets per drawing (default 3) and Drawings in parallel.
4. Click Start and open the Output tab: one row per drawing.

Supported files are PDF (vector or scanned), PNG, JPG, TIFF and WebP. Each link must be a direct download link that doesn't need a login.

Input example

{
  "drawingUrls": [
    "https://example.com/drawings/part-1001.pdf",
    "https://example.com/drawings/part-1002.png"
  ],
  "maxPagesPerDrawing": 3,
  "maxConcurrency": 3
}

Output example

One item per drawing (shortened; the full item also has details with every dimension, thread, GD&T frame and roughness callout):

{
  "status": "ok",
  "fileName": "sample-shaft.pdf",
  "drawingNumber": "TDR-1002",
  "revision": "A",
  "title": "DRIVE SHAFT",
  "material": "42CrMo4+QT",
  "generalTolerance": "ISO 2768-fH",
  "units": "mm",
  "tightestTolerance": 0.013,
  "tightestToleranceCallout": "2x Ø25 k6",
  "tightestGeometricTolerance": 0.005,
  "tightestGeometricCallout": "Cylindricity 0.005",
  "finestRoughnessRa": 0.4,
  "toleratedDimensionCount": 6,
  "threadCount": 1,
  "gdtCount": 3,
  "attentionPoints": [
    "Tight tolerance: 0.013 mm band on \"2x Ø25 k6\"",
    "Very tight geometric tolerance: cylindricity 0.005 mm",
    "Fine surface finish required: Ra 0.4 µm",
    "Heat treatment: Induction hardened 50-55 HRC, depth 1-1.5 mm on Ø25 seats",
    "Fine-pitch thread: M16x1.5-6g"
  ],
  "warnings": [],
  "pagesCharged": 1
}

A dimension inside details.toleratedDimensions:

{
  "raw": "Ø30 h7",
  "nominal": 30.0,
  "fitClass": "h7",
  "upperDeviation": 0.0,
  "lowerDeviation": -0.021,
  "toleranceBand": 0.021,
  "toleranceSource": "iso286"
}

toleranceSource tells you where a band comes from:

• drawing: printed on the sheet.
• iso286: computed from the fit class, with exact limits.
• iso286-band-only: computed from the fit class. The band width is exact, but the limits aren't given for that deviation letter.

The Overview and Problems tabs in the Output show the key fields and any warnings at a glance. You can download everything as JSON, CSV, Excel or HTML.

How much does it cost?

This Actor uses pay-per-event pricing: you pay per drawing sheet analysed (event drawing-page-analyzed). The price is shown on the Actor's pricing tab.

• A typical one-sheet part drawing costs one event.
• Only the first Max sheets per drawing sheets of each file are read and charged.
• Sheets that fail to read are not charged.
• The bundled sample drawings and the empty-input demo are free.
• Your spending limit is respected. Before a drawing is read, its sheets are reserved against your maximum cost for the run. When the limit is reached, the remaining drawings are marked skipped and not charged.

Accuracy and limitations

Please read this before relying on the output.

• The output is an aid for quoting and data entry, not a replacement for engineering review. Always check critical values against the drawing before manufacturing or committing to a price.
• Clean CAD exports (vector PDF) give the best results. Low-resolution scans, handwriting, heavy hatching over text or very dense sheets can cause missed or misread callouts. Each item includes warnings and per-section confidence values, and readings below 0.6 confidence are flagged.
• ISO conventions are assumed (ISO 286, ISO 2768, ISO 1302, ISO 261). Inch drawings are read, but ISO fit calculations are not applied to them.
• Only fields printed on the drawing are returned. Person names (designer, checker, approver) are deliberately not extracted.
• 3D models (STEP, IGES), DXF/DWG files and multi-part assembly BOMs are not supported.

Privacy

Drawings are downloaded only to process the run and are sent to the AI provider to be read. They are not used to train models. Links to private networks are refused. Only use drawings you're allowed to share with a third-party processor.

FAQ

Can I process drawings from Google Drive or Dropbox? Yes, if the link is a public direct download link, not a preview page.

Why does Apify ask me to approve permissions on the first run? The Actor needs permission to read the drawing files you upload through the Upload drawings field, which are stored in your own Apify storage. It only reads the files you give it in the input.

What happens with a multi-sheet PDF? Each sheet up to Max sheets per drawing is read, and the results are merged into one item per file. The title block is taken from the first sheet that has one, and all dimensions are listed with their page number.

Can I call it from my own software? Yes. Use the Apify API or one of the API clients. Start a run with the input JSON above and read the default dataset.

Something was read wrong. What can I do? Check warnings, confidence and the raw text of the callout. Please report systematic problems through the Issues tab with a drawing you're allowed to share. That's how the reader gets better.