How to turn a photo into a 3D printable STL: free, in your browser

A broken gasket, a bent bracket, a missing cover plate: if the part is flat, you don't need CAD to recreate it. You need a photo and about five minutes.

This guide uses Ez3D, a free part designer that runs entirely in your browser. There's no account and no upload, because the photo is processed on your own device and never leaves it. The result is a clean, watertight STL (or 3MF) that opens in any slicer.

What you need

The flat part you want to copy (or a paper tracing of it)
A phone or camera
A sheet of plain paper, and ideally a ruler for scale

Step 1: Take the photo

Lay the part on plain white paper and shoot from directly above, as straight-on as you can. Contrast is what matters: a dark part on light paper traces best. Avoid harsh shadows; indirect daylight is perfect. If you can lay a ruler next to the part in the same shot, scaling later becomes effortless.

Step 2: Trace it

Open the app and click 📷 Trace photo, then pick your photo. Ez3D finds the part's outline automatically; if the lighting was tricky, a couple of sliders (brightness, threshold) clean it up. You can also drag any point of the outline to fine-tune it by hand.

Step 3: Set the real size

Click two points a known distance apart, like the ruler in your photo or any dimension you've measured, and type that distance in millimeters. Everything scales to match, 1:1. No ruler? Just type the part's overall width on the review step.

Step 4: Holes and cutouts

Ez3D detects enclosed holes and classifies them as round holes, slots, or rectangular cutouts, turning them into true geometric features instead of pixelated blobs. Accept the ones you want and type exact diameters (a 5 mm bolt hole stays exactly 5 mm).

Step 5: Thickness, then export

Type how thick the part should be (measure the original with calipers, or hold it against a ruler), click Make part, and you'll see it in 3D on a print bed. A built-in print check confirms it fits your printer. Click Export STL and open the file in Bambu Studio, PrusaSlicer, Cura, or any other slicer.

No photo handy? The same tool lets you draw the part by hand (freehand, rectangles, circles, or point-by-point) and add holes the same way. Handy when the original part is lost entirely.

What this works best for

Anything flat with a constant thickness: gaskets, mounting brackets, cover plates, spacers, shims, wall-hook backplates, blanking plates, jigs. For complex curved parts you'll still want real CAD. But the honest truth is that most of what breaks around a house, shop, or job site is a flat part.