3D Printing / Publishing

Publishing a 3D Model: the Licence Traps, and Why the Default Selection Is the Worst One

You finish a model, open the upload form, and the licence dropdown is already set to something. On at least one major platform that default is Creative Commons Public Domain, which lets anyone sell prints of your work and remove your name from it. Creative Commons grants cannot be revoked. The first upload is the one that counts, so this is a decision to make before you click, not after.

Read the words, there is no version number to look for

The licences are spelled out in full on the form, with no abbreviation and no "4.0" anywhere. If you are scanning for CC BY-NC-ND you will decide the option is missing. What you are looking for reads:

Creative Commons — Public Domain                                   <-- often the default
Creative Commons — Attribution
Creative Commons — Attribution — Noncommercial
Creative Commons — Attribution — Noncommercial — NoDerivatives     <-- the strictest CC option

Set it explicitly on every platform you upload to. Do not assume one site's choice carries to the next.

What each term actually stops

NonCommercial is the load-bearing one. It is what stops someone selling prints of your model. If you only add one term, add this one.
NoDerivatives is narrower than it sounds. It stops modified re-uploads. It does not stop redistribution.
Attribution is the floor. Everything except CC0 requires your name to travel with the file.

BE WARNED: even the strictest CC licence permits unlimited verbatim mirroring. CC BY-NC-ND explicitly allows anyone to copy your unmodified STL onto any site they like, free, forever. That is fine for a model you are giving away. It is exactly why you should never put a model you intend to sell under any Creative Commons licence. For paid work, use the platform's own proprietary licence. And since the grant is irrevocable, you cannot fix this later by changing the dropdown.

The caveat nobody enjoys: AI-generated meshes may not be yours to license

A licence only works if you hold copyright in the thing being licensed. In the US, purely AI-generated work likely attracts no copyright at all, so putting CC BY-NC-ND on a mesh a generator produced is closer to a statement of intent than an enforceable term.

Mixed work gets awkward rather than better. A functional part you modelled yourself in parametric CAD has thin protection anyway, because useful articles are poorly covered. The decorative element, which is what copyright protects most readily, is often the generated part. So the strongest-looking half of your model is frequently the half you have the weakest claim to.

The real protection for anything you plan to sell is not the licence. It is holding the source files, the tested print profile and the knowledge of what fails, none of which ship inside an STL.

What the platforms actually pay, checked rather than assumed

Publishing advice ages badly. These were verified in August 2026, and the differences matter enough to change where you put a given model:

MakerWorld has no paid-download option at all. Not a low rate, none. Earnings come from points, a Commercial License Membership others subscribe to, and commission on kit orders. If your plan was to sell a file there, the plan does not exist.
Printables has a store, with real constraints. Paid listings start at a $5 minimum, a model is free or paid rather than both, and new accounts get one paid slot until they make sales. Spending that single slot on a free-feeling model is a decision worth making deliberately.
MyMiniFactory has two upload paths and this is the usual point of confusion. Objects is free and open to all creators. Shop3D is the paid flow and needs a paid Premium Creator subscription. Free accounts also cap uploads at 100MB, and review is manual.
Cults3D is the straightforward one for selling. No minimum price, no slot limit.

Cover image rules have teeth now

MakerWorld has required since February 2026 that the cover image be a photograph of a real print matching the file. Renders are banned as covers. Tag AI-assisted work as AIGC.

These rules are not really anti-AI, they are anti-misrepresentation. They exist because people listed renders of models nobody had ever printed, and buyers got files that do not work. Disclose the generation, print the thing, photograph the print, and you are on the right side of every one of them without having to track individual policies.

Ship the gcode, and warn about it in bold

Including sliced gcode is genuinely useful, and it is the one file in the pack that can damage hardware. Gcode carries absolute coordinates, temperatures and your specific machine's start macro. On different hardware it fails at best, and drives the head into the bed at worst.

So label every gcode file with the machine and nozzle it was sliced for, put a bold machine-specific warning in the README, and verify each one came from the 3MF you actually shipped. An exported 3MF archive usually embeds its own sliced gcode already, so it is easy to end up shipping two versions that disagree.

Before any of that, check the model itself will print. See catching the print that will fail before you spend the filament.

When this isn't your problem

You genuinely want CC0. Then the default is correct and you can stop reading. Just make it a choice rather than an accident.
You are printing for yourself. No licence needed for anything you never publish.
You are remixing someone else's model. Then their licence constrains yours, and a ShareAlike term forces your derivative to carry it too. Check the source before you pick anything.