What does an outsourced STL rebuild cost? A $150-per-file quote, and the logic behind it
Turning an STL back into an editable STEP is possible, but it is not something you can press a button to do. This page reads the price of that work out of a service’s own landing page, captured on the Wayback Machine in 2020, and sets it next to the direction this site actually runs — which is machine work and finishes in a browser tab. No figure here is offered as a current price; the numbers are what one page said in 2020.
The short answer
An outsourced STL-to-STEP rebuild is priced as a person’s time, not as computer time. The clearest evidence is a landing page captured in 2020 that sold exactly this job: As low as $150 / file, with Most conversions take less than a day to complete, and an order form that made you choose the kind of STEP you wanted before anyone touched the mesh — a Solid File or a Surface File. Those three facts belong together, and together they describe labour rather than software: a price per file, a delivery measured in a working day, and a buyer who has to name the deliverable up front because a person is going to draw it. The vendor of that service said the same thing outright — there is no one-button press to convert a STL (or OBJ) to STEP for use in CAD software. The reason this direction carries a price at all is that no kernel recovers a circle from a ring of triangles; a person rebuilds it. The opposite direction, STEP to STL, is sampling: it is machine work, it runs here for nothing, and the only limit the old server-side era published was a cap on how much machine time the operator would pay for.
The 2020 quote, line by line
The capture is a Wayback Machine copy dated 24 September 2020 of stl2step.com, a reverse-engineering service run by 3DChimera. It is a dead vendor page, and this page describes it as the snapshot shows it, no more. Three lines on it are worth reading together, because they describe a price for human work rather than a price for a machine.
| What the page said | What it tells you about the price |
|---|---|
| “As low as $150 / file” | The unit is a file, not an hour, a polygon or a megabyte. A per-file price is what a supplier quotes when the work scales with the person doing it rather than with the size of the input. |
| “Most conversions take less than a day to complete” | The clock is a working day, not seconds. The bottleneck is a person’s schedule, not a processor’s queue. |
| Order form: “Type of STEP file desired” — pre-select Solid File or Surface File | You must name the deliverable before work starts, which means the output is not a fixed function of the input. It is a choice the shop carries out. |
The same capture states the cause in one sentence: “there is no one-button press to convert a STL (or OBJ) to STEP for use in CAD software”. That is a vendor of the reverse conversion saying that its product is a person, not a checkbox. It also explains the other two lines. When the work is a person, you bill per file because a person’s effort does not track the triangle count; you promise a working day because a person works in days; and you ask the buyer to name the deliverable because a person, not a program, is deciding how to fit surfaces to the mesh.
Why a rebuild costs a person’s time, and a forward conversion does not
Set the two directions side by side and the price becomes obvious. In the forward direction — STEP to STL — the only scarce thing in the old server-side era was machine time, and operators metered it. The 2009 help FAQ of an early upload service put a cap of 100,000 polygons on free files and gave the reason in money: processing time cost them money, so the ceiling was how much machine time they would pay for on your behalf (why the upload existed at all). In the reverse direction there is no such machine to meter, because no kernel recovers exact surfaces from a mesh. What is scarce is the engineer, and an engineer is metered in files and days. The 2020 capture’s three lines are simply that scarcity written as a price list.
The same domain pointed at this fact for years. A long-running manual service at stltostep.com sat on the exact same search for nine years — a second independent witness, captured on the Wayback Machine, that the reverse direction was sold as a human service and never shipped as a program. Repair of mesh in the same era was sold the same way, as a cloud service you handed a file to; those automatic repair endpoints are gone now, which is a history the holes page keeps. None of that is a machine you can run yourself.
Three ways from an STL to a STEP, and what each costs
- Rebuild it yourself in CAD. Open the tool you already own and draw the part over the mesh, using the triangles as a trace. This costs your own hours and no money, and it is the only route that returns a parametric part with its feature tree intact. The rebuild page walks the two-step version: accept what the mesh holds, then rebuild.
- Outsource it, per file. This is the route the 2020 capture priced: As low as $150 / file, most jobs delivered in under a day. You are buying an engineer’s hours against a fixed price and a delivery clock, not buying software.
- Let a script guess. A plain script with no kernel cannot tell a circle from a fan of panels; it fits what it can and writes a spline where the circle was. It is the cheapest line and the one that gives the least of the part back. The reverse-direction page explains why a kernel, not a script, is what a reconstruction tool really sells — and why such a tool still needs a person to clean up after it.
What this site does is none of those three. The converter here reads STEP and IGES and writes STL — one direction, no fee, nothing uploaded. It will not take an STL as input and it does not sell rebuilds. The reason the two directions differ so sharply in price is the same reason this site can run its direction for free: converting the other way is a person, and this way is a kernel.
The direction this site does run, measured
The forward direction does not need a person because the surfaces already exist and are simply walked into triangles. This site ships the OpenCASCADE kernel as a WebAssembly file of 7,604,031 bytes (7.25 MiB), fetched once per session from this site’s own folder and then run in a worker inside your tab. The numbers are measured by the test suite on every run, and the same suite refuses to publish this page if they move: a flat 10 mm cube stays 12 triangles and 684 bytes at every quality setting, and an 18-part assembly measuring 433,606 bytes of STEP comes back as 7,372 triangles in a 368,684-byte STL at Normal, with nothing uploaded. The machine that used to need a server, and the person who used to need a purchase order, are two different costs, and only one of them is paid here.
Questions this page answers
How much does it cost to rebuild an STL as a STEP file?
It is priced per file, as a person's time, and the one figure this page can point to is historical. A Wayback Machine capture of a US reconstruction service dated 24 September 2020 opened its own price list at "As low as $150 / file", with the delivery promise "Most conversions take less than a day to complete". That was one vendor's 2020 rate for one file. It is not a current market price, and this page does not claim it is.
Why is a rebuild priced per file instead of per triangle?
Because the work scales with the person, not with the input. A per-file price is what a supplier quotes when the same job can take a different amount of human effort regardless of how large the mesh is, and a promise measured in a working day is a promise about a schedule rather than a processor. The same 2020 capture made the buyer pre-select the kind of STEP wanted before any work began, because the output is a choice a person carries out, not a function of the file.
Can a script convert STL to STEP for free instead?
Not to an editable model. Going from triangles back to surfaces is reconstruction, and a plain script has no kernel to fit a circle to a ring of panels — it can only guess, and what it guesses comes back as a spline where a circle belongs. The services that sold this work said the same thing in 2020: there is no one-button press to convert a STL (or OBJ) to STEP for use in CAD software. A person with a CAD kernel rebuilds the part; a button does not.
Does this site rebuild my STL into a STEP for a fee?
No. The converter here reads STEP and IGES and writes STL — one direction only. It will not take an STL as input and it is not a paid rebuild service. This page is about the price other people charged for the reverse direction in 2020, and about why the forward direction this site does run, STEP to STL, is machine work that costs nothing here and runs inside your browser tab.
Where these numbers come from
- “As low as $150 / file”, “Most conversions take less than a day to complete”, “Solid File”, “Surface File” and “there is no one-button press to convert a STL (or OBJ) to STEP for use in CAD software” — read from a Wayback Machine capture of stl2step.com, dated 24 September 2020 and run by 3DChimera, kept in this project’s research folder; the test suite reads the archived file and requires each quoted string before the page may print it. The 2020 wording is quoted as the snapshot shows it.
- nine years at stltostep.com — the companion archived capture of the same reverse-direction service, kept in the same research folder; the suite reads it and requires the date the page prints. Two dead domains, one fact: the rebuild was sold as a person.
- 7,604,031 bytes, 12 triangles, 684 bytes, 433,606 bytes → 7,372 triangles → 368,684-byte STL — the kernel file’s length on disk and the project’s own measured conversions, re-run by
npm teston every release. These describe the forward direction only. - What we do not claim — we do not run a reverse conversion, we sell no rebuild, and we print no current price for one. The only price on this page is a dated 2020 quote from a vendor page that is quoted as such. The verification page owns the format rejection list; this page links to it rather than repeating it.
npm testThe command above re-runs every number on this page. The reverse-direction page owns the question of whether STL to STEP is a conversion at all; the rebuild page owns the method; the upload-history page owns the machine-time cap the forward era charged for; the mesh-era page keeps the format-board history; and the converter is where a STEP file meets the kernel, for free, in the tab.