DXF Part Calculator

Get cut length, pierce count, part area and a rough quote from DXF files in one command. Built for laser, plasma, waterjet and CNC router shops that quote from customer drawings, and for developers building instant quoting into a website or ERP.

Plain .NET 8, no dependencies. Text, JSON and SVG preview output.

Previews from --svg: part outline in black, holes in blue, open paths dashed orange, pierce points in red.

Example

$ dxfcalc samples/bracket.dxf --speed 3000 --pierce 0.8 --rate 90 --material 45 --qty 10

File            bracket.dxf
Units           mm
Size            120.00 x 80.00 mm
Cut length      534.25 mm
Pierces         4  (1 outer, 3 holes, 0 open)
Part area       4,717.83 mm²  (47.18 cm²)
Bounding area   9,600.00 mm²
Utilisation     49.1 % of the bounding rectangle
Entities        CIRCLE 2, LWPOLYLINE 2
Skipped         DIMENSION 1, TEXT 1

Cut time        0.23 min each
Machine         0.35 each
Material        0.43 each (bounding rectangle)
Total           0.78 each, 7.79 for 10

Pass several files or a folder and you also get a summary table:

$ dxfcalc samples/

File                         W x H (mm)               Cut (mm)  Pierces     Area (mm²)
bracket.dxf                  120.00 x 80.00             534.25        4       4,717.83
cover-plate.dxf              152.40 x 101.60            761.69        3      12,340.47
flange.dxf                   150.00 x 150.00            885.93        8      14,165.36
Total                                                 2,181.87       15      31,223.67

What it handles

Entities	LINE, ARC, CIRCLE, LWPOLYLINE with bulges, 2D POLYLINE, ELLIPSE, SPLINE (rational NURBS), INSERT (nested, scaled, rotated, mirrored blocks)
Broken outlines	Joins separate lines and arcs into contours, in any order and direction, within a tolerance
Holes and islands	Detects nesting: outline, hole, island in a hole, so the area is the real material area
Messy exports	Removes entities and contours drawn twice, reports open contours
Annotation	Skips TEXT, MTEXT, DIMENSION, HATCH and friends; --ignore-layers for anything else (bend lines, notes)
Units	Reads $INSUNITS (mm, cm, m, in, ft...). Warns when missing, --units to override
Mirrored geometry	Handles object coordinate systems with a flipped extrusion, common in mirrored parts
Formats	ASCII DXF from R12 to current versions. Binary DXF is detected and rejected with a clear message

Accuracy

Lengths of lines, arcs, circles and bulge segments are computed exactly. Ellipses, splines and non uniformly scaled arcs are measured on a fine polyline (chord error 0.002 mm by default). On the samples, results agree with hand calculation to within 0.003%.

Sample	Expected cut length	dxfcalc
flange.dxf (Ø150, Ø60 bore, 6 x Ø12 via block inserts)	885.93 mm	885.93 mm
bracket.dxf (L bracket, R10 fillet, 2 holes, slot)	534.25 mm	534.25 mm

Options

dxfcalc <file.dxf | folder> [...] [options]

Analysis
  --units <mm|cm|m|in|ft>     override the drawing units
  --ignore-layers <a,b,...>   skip layers, wildcards allowed: "DIM*,TEXT,BEND"
  --join-tolerance <mm>       max gap when joining entities (default 0.05)
  --svg <file|folder>         write a preview SVG
  --json                      machine readable output

Quote
  --speed <mm/min>            cutting speed for the material and thickness (required for a quote)
  --pierce <seconds>          time per pierce (default 0.5)
  --rate <per hour>           machine rate
  --material <per m²>         sheet price, charged on the bounding rectangle
  --qty <n>                   quantity

How the quote works: cut minutes = cut length / speed + pierces × pierce time, machine cost from the hourly rate, material from the bounding rectangle area. It is deliberately simple; real nesting and per material tables are a natural next step.

Using it from code

The analysis is a library behind a thin CLI:

var part = PartAnalyzer.Analyze("bracket.dxf", new AnalysisOptions { IgnoreLayers = ["BEND*"] });

Console.WriteLine($"{part.CutLengthMm:F1} mm, {part.Pierces} pierces, {part.NetAreaMm2:F0} mm²");

var quote = QuoteCalculator.Calculate(part, new QuoteOptions
{
    CutSpeedMmPerMin = 3000, PierceSeconds = 0.8, RatePerHour = 90, MaterialPerM2 = 45
});

That makes it easy to put behind an ASP.NET endpoint for an upload and instant quote page.

Build and test

git clone https://github.com/softechies/dxf-part-calculator.git
cd dxf-part-calculator
dotnet test
dotnet run --project src/DxfPartCalculator -- samples/flange.dxf

The sample files are generated by samples/generate_samples.py using ezdxf, so the tests run against output from an independent DXF writer.

Project layout

src/DxfPartCalculator/
  Dxf/         ASCII DXF reader: header, blocks, entities
  Geometry/    transforms, arcs, bulges, ellipses, NURBS, entity conversion
  Analysis/    contour joining, nesting, area, duplicates, quote
  Output/      text, JSON and SVG reports
tests/         geometry, analyzer and sample file tests
samples/       example parts and the script that generates them

License

MIT

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Built and maintained by Softechies Solutions. We build CAD/CAM utilities, instant quoting portals and manufacturing software in .NET and on the web.