GasketDXF Generator
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1:1 gasket CAD · ASME / EN library · photo tracer · mm / in

Photo to Gasket DXF Converter

Photograph the old gasket next to a ruler, drag two handles onto a known distance and the outline is traced in millimetres with every bolt hole snapped to a true circle.

Demo
photos

View 0 · Photo & calibration

traced outlinetrue-circle holescalibrationdrag nodes · double-click adds · Delete removes · Ctrl+Z undo

View A · 2D blueprint

Min web—SAFE—
PROOF ONLY — NOT 1:1 SCALE
OUTER_CUTINNER_BOREBOLT_HOLESCENTERLINESweb < 2.5 mm
Outer × inner
—
Bolt pattern
—
Bolt chord S
—
Ligament S − d
—
Hole → bore
—
Hole → outer edge
—
Area
—
Weight
—
Cut outer (+kerf)
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Cut bore (−kerf)
—
Cut bolt hole
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    View B · 3D extrusion

    drag to orbit · wheel to zoom
    Hole coordinates · polar & XY from the centre
    HoleAngleRadiusXY

    Export

    this exact gasket
    Free screen proof · not to scale
    Pro 1:1 production files
    Early Launch Price

    How to

    Old gasket to clean CAD in four steps

    1. Shoot it flat, from abovePlain contrasting background, even light, a ruler or two dowel pins in the frame.
    2. Upload and check the traceThe outline (cyan) and true-circle holes (amber) appear on the photo in a second.
    3. CalibrateDrag handles 1 and 2 onto the known marks, type the distance, press Calibrate.
    4. Tidy and exportDrag nodes or delete stray holes, then export the DXF, SVG, STL or 1:1 PDF.

    The photo

    How to shoot a photo that traces well

    Most bad traces come from the photo, not the tracer.

    GOOD — square-on, flat, even light ruler marks = known distance BAD — angled, shadow, cropped holes turn oval, outline is cut off Fill most of the frame; keep the camera parallel to the gasket.
    Square-on, flat, evenly lit and with a ruler in frame (left) traces cleanly; an angled, shadowed, cropped shot (right) turns holes into ovals.
    • Hold the phone parallel to the gasket; use the camera grid or a small level.
    • Put the gasket on white paper (or a dark mat for light gaskets) and avoid the flash.
    • Fill about 70 % of the frame and keep the whole outline inside it.
    • Lay a steel ruler or two dowel pins at a known distance on the same plane as the gasket.

    Under the hood

    Calibration and true-circle snapping

    The tracer converts the photo to luminance, picks the threshold between gasket and background with Otsu's method (you can override it), keeps the largest dark region as the gasket and follows its boundary. Every background region fully enclosed by the gasket becomes an inner contour.

    Round, small contours are fitted with a least-squares circle and become bolt holes; the rest stay polylines on the INNER_BORE layer, shown as an equivalent "≈ Ø" diameter. Three or more holes on one circle give a bolt circle (PCD) when the fit residual is under 1 %.

    Demo photos and what they trace to
    DemoCalibrationOutlineHoles
    Pump flange336 px = 84.0 mm → 4.000 px/mm100.0 × 100.0 mm, bore ≈ Ø50.04 × Ø10.0 on PCD 75.0
    2-bolt exhaust400 px = 100 mm → 4.000 px/mm131.0 × 75.5 mm, bore ≈ Ø63.52 × Ø12.0
    Side cover252 px = 84.0 mm → 3.000 px/mm180.0 × 120.0 mm10 × Ø6.5

    Accuracy

    What accuracy to expect

    A 4 px/mm photo resolves 0.25 mm per pixel; the boundary is placed between pixels, so a clean edge measures within about one pixel. Lens distortion and tilt add more, which is why the honest figure is about ±0.5 mm on a 100–200 mm part.

    Before you cut, compare the traced bolt-hole spacing with calipers, or rebuild a round flange exactly in the flange gasket outline DXF page using the traced PCD as a starting point.

    Privacy

    The photo never leaves your browser. Only after calibration, and only when you export a Pro file, are the outline points in millimetres and the hole list sent to build the file in memory — not the image.

    Use cases

    When a photo is faster than measuring

    FAQ

    Questions from the shop floor

    Short, specific answers. Open a question to read it.

    Which photos work?

    PNG, JPG or WebP up to 10 MB, shot straight down with the gasket flat on a plain surface that contrasts with it — a dark gasket on white paper or a light one on a dark mat (tick Invert). Put a ruler or two dowel pins of known spacing in the frame. Other file types are refused before decoding.

    How does two-point calibration work?

    You drag handle 1 and handle 2 onto two marks whose real distance you know and type that distance in mm. The pixel distance divided by the millimetres is the scale, shown as px/mm. The fixture photo gives 336 px for 84.0 mm, so 4.000 px/mm, and the 400 px gasket measures 100.0 mm.

    What does "true circle" mean for the holes?

    A camera rarely sees a hole as a perfect circle. Every closed region inside the gasket that is round enough (circularity 4πA/P² ≥ 0.80) and small enough is fitted with a least-squares circle, so the DXF gets a CIRCLE with an exact centre and diameter rounded to 0.1 mm instead of a wobbly polyline.

    How accurate is it?

    With a square-on photo, the gasket flat and a ruler in the frame, about ±0.5 mm on a 100–200 mm part; hole centres are usually better because the fit averages the whole edge. There is no perspective correction, so check critical spacings with calipers.

    Can I fix the trace by hand?

    Yes. Drag any outline node, double-click a line to add a node, select a node or hole and press Delete, use the Delete hole button, and Undo (or Ctrl+Z) up to 50 steps. Reset trace brings back the automatic result.

    Is the photo uploaded?

    No. Decoding, thresholding and tracing run inside your browser, in a background worker. When you export a Pro file only the calibrated outline in millimetres and the hole list are sent to build the file in memory; the photo itself never leaves your device and nothing is stored.

    The gasket family

    Same engine, a page for each job

    Every tool page opens the same studio with its own examples; the guides explain the numbers.