Prompt contract: one solid part
This is the scope contract for FreeTextToCAD. Read it before you write a prompt — especially if you are about to paste a long brief.
The scope contract
Exactly one solid part per generation. Name the part and give millimetre sizes. Detail is welcome: fully dimensioned briefs do succeed here, and in our logs the prompts that get accepted most often run 200–500 characters. What fails is scope, not length — a hinge, a lid, a sliding mechanism, or several objects will be refused however well the request is written.
A longer, more complete brief is not a better prompt here. Users who paste a 2,000-character specification almost always quit at the confirm step — before any geometry is attempted. Retrying the same brief fails the same way. Distill first.
In scope: hooks, brackets, washers, spacers, knobs, mounts, enclosures, trays, adapters, funnels, clips, simple gears, nameplates. One body. Millimetres.
Out of scope everywhere on this site: assemblies with moving parts, figurines / characters / animals from text, multi-body scenes, production drawings, STEP/IGES.
Open the generator with the prompt already written
/generator?prompt= prefills the workspace. Write a correctly scoped prompt, URL-encode it, and use that link. Do not start from the homepage with a specification still in the chat.
Worked example. Prompt:
A 30mm wall hook with a 4mm screw hole at the top and a 25mm arm
If that is not the ask
- Figurine, character, animal, toy soldier from text — not supported. Have a picture? Photo to 3D Print.
- Vase, bowl, urn, decorative form from text — not supported. To draw it by hand, CAD Studio.
- Logo, face, photo, likeness — Photo to 3D Print. Needs an image.
- Assembly, slider, hinge, moving mechanism — pick one part for the Generator, or sketch in CAD Studio.
- Several objects in one ask — refuse the set. Offer one part if a single solid exists.
Do not invent a washer for someone who asked for a soldier. Licensed characters are refused on every path.
How to decompose
Given a mechanism or a specification, hand over one dimensioned solid — not the whole project. Then generate the next part.
1. Sliding razor-blade assembly
Bad: an assembly that holds a razor blade and slides along an axis. That is a moving mechanism.
Good: Blade holder body, 80x25x18mm, with a 0.5mm-wide x 22mm-deep slot along the length and a 6mm through-hole for a rod.
2. Two-thousand-character money-box specification
Bad: a full engineering brief for a gift money box, with headers, banknote tables, and print-process notes.
Good: Open-top box, inner 152x67x20mm, 2mm walls, 2mm floor, for 150x65mm banknotes.
3. Playing-card holder written as a spec sheet
The object is in scope. The document is not.
Good: Card holder, 80x40x30mm, with one 2mm-wide x 70mm-long slot to stand 5 playing cards.
Wrong tool — do not decompose into a fake part
- A toy soldier from text — refuse. Photo to print only if you have a picture.
- Ten mystery boxes and ten movie figures — refuse the figures. A plain box is a separate ask:
Closed box 80x80x80mm, 2mm walls. - A replica Xbox controller shell — not a box with holes. A simple open tray at stated millimetre sizes is the honest rewrite.
Language
Prompts may be written in any language. The site accepts them and, when triage runs, distills geometry into an English millimetre brief. French, German, and Spanish unit words are converted to millimetres. Engraved lettering on a part supports A–Z, 0–9, and a small punctuation set — not accented or non-Latin glyphs.