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Text to STL with AI
Text to STL for parts that have to fit
Text to STL means typing what a part is and getting a file your slicer accepts. SpeakCAD is the mobile-first AI 3D editor for 3D printing: describe a part in plain English on your phone or computer and get an instant, print-ready STL or 3MF, or G-code already sliced for your printer. Every size you give is used to the millimetre, because the AI writes a parametric CAD program for the part instead of sculpting a mesh that looks like it.
How it works
From a sentence to a file your printer accepts
Text to STL works best when the text reads like a drawing: the outer size, the wall thickness, what the part fits and how it mounts. Anything you leave out is decided from FDM design rules and reported back.2
Check the render
The first render usually appears within a minute or two: a new part goes to the strongest models, which reason through the geometry, and small edits land in seconds. Turn the part, tap a face to read its size, open the dimensions panel to see every number it was built from, and check the overhangs.3
Change it by chat or by number
“Make the hook 10 mm deeper”: one request (2 credits), and the rest of the part stays as it was. Typing a new number in the dimensions panel is free.4
Download STL, 3MF or G-code
A watertight, manifold STL or 3MF in millimetres (10 credits), or G-code sliced with the official OrcaSlicer profile of one of 380+ printers.Text to STL (CAD) vs text to 3D (mesh)
| Text to STL (CAD, as in SpeakCAD) | Text to 3D (mesh, as in Meshy or Tripo) | |
|---|---|---|
| Sizes | Exact: every millimetre you type becomes a named parameter | Approximate: you scale the mesh afterwards, and holes and walls scale with it |
| The file | Watertight, manifold STL or 3MF by construction | A sculpted mesh: check it for holes and thin walls before slicing |
| Changing it | Change one number or say one sentence; the rest of the part stays | Generate again, or edit the triangles in a mesh editor |
| Holes and clearances | Placed where you said, with fit clearances for FDM printing | Hard to control from a prompt |
| Printing | STL or 3MF for your slicer, or G-code sliced for 380+ printers | A mesh file for your own slicer (formats: check their site) |
| Looks | Plain solid geometry, one colour | Detailed, textured, coloured models |
| Best for | Brackets, enclosures, holders, adapters, replacement parts | Figurines, characters, sculptures, props |
SizesText to STL (CAD, as in SpeakCAD): Exact: every millimetre you type becomes a named parameterText to 3D (mesh, as in Meshy or Tripo): Approximate: you scale the mesh afterwards, and holes and walls scale with it
The fileText to STL (CAD, as in SpeakCAD): Watertight, manifold STL or 3MF by constructionText to 3D (mesh, as in Meshy or Tripo): A sculpted mesh: check it for holes and thin walls before slicing
Changing itText to STL (CAD, as in SpeakCAD): Change one number or say one sentence; the rest of the part staysText to 3D (mesh, as in Meshy or Tripo): Generate again, or edit the triangles in a mesh editor
Holes and clearancesText to STL (CAD, as in SpeakCAD): Placed where you said, with fit clearances for FDM printingText to 3D (mesh, as in Meshy or Tripo): Hard to control from a prompt
PrintingText to STL (CAD, as in SpeakCAD): STL or 3MF for your slicer, or G-code sliced for 380+ printersText to 3D (mesh, as in Meshy or Tripo): A mesh file for your own slicer (formats: check their site)
LooksText to STL (CAD, as in SpeakCAD): Plain solid geometry, one colourText to 3D (mesh, as in Meshy or Tripo): Detailed, textured, coloured models
Best forText to STL (CAD, as in SpeakCAD): Brackets, enclosures, holders, adapters, replacement partsText to 3D (mesh, as in Meshy or Tripo): Figurines, characters, sculptures, props
Text that makes a good STL
Three functional parts written the way that works: sizes in millimetres, what the part fits, how it mounts. Each opens in the editor with the text already typed.“A desk-edge cable holder that clamps a 25 mm thick desktop with 0.3 mm clearance, five 7 mm cable slots on top 15 mm apart, 3 mm walls, printed on its side.”
Open this prompt in the editor“A replacement battery cover 58 x 32 x 2 mm with a 12 mm wide spring latch on one short side and two 3 x 2 mm locating tabs on the other, 0.2 mm clearance all round.”
Open this prompt in the editor“An adapter from a vacuum hose to a dust port: 32 mm outer diameter on one end, 40 mm inner diameter on the other, 50 mm long, 2.4 mm walls, a slight taper on both ends.”
Open this prompt in the editorWhat text to STL means here
Most tools sold as "text to STL" are text-to-3D generators: they turn a prompt into a mesh that looks like the thing. That is great for a dragon and poor for a bracket that has to take two M4 screws 40 mm apart. SpeakCAD does text to CAD: the AI writes a parametric OpenSCAD program from your description, the browser compiles it into exact geometry, and the STL comes out of that program. Hence exact sizes, watertight meshes, and edits that change one number instead of regenerating the whole part.
How to write text that becomes a good STL
- The outer size first, in millimetres.
- What it fits, holds or attaches to. "Fits a 20 mm pipe", "holds a 58 x 38 mm board": that sets the clearances.
- How it mounts. M3 or M4 screws, clips, adhesive pads, magnets with their size.
- The material, if it matters. PETG outdoors, TPU for a bumper, ASA in a hot car.
- Nothing you do not care about. The AI picks the rest from FDM rules (wall thickness, a flat base, printable overhangs) and says what it assumed.
More in prompting for CAD.
When Meshy or Tripo fits better
If the part is about looks rather than fit (a figurine, a character, a sculpted vase, a tabletop miniature), a mesh generator such as Meshy or Tripo is the better tool: it makes organic shapes and textures that a CAD program does not. SpeakCAD builds solid, functional geometry: boxes, brackets, holders, adapters, knobs, gears. SpeakCAD vs Meshy and SpeakCAD vs Tripo go through where each one wins, and the best AI CAD tools for 3D printing compares the text-to-CAD options.
Already have a description, a file or the object?
- ChatGPT or another assistant wrote the spec: paste it as it is, see ChatGPT to STL.
- An STL that is almost right: edit it instead of starting over.
- The object itself: duplicate it from two phone photos next to a ruler.
What it costs
Free, without a card: the live demo (3 AI edits of a real part, no account) and the 650+ ready-made library models, which open in a free account and resize in the viewer. Your own part uses credits. Starter credits: 75 credits for $5 once (50 + 25 free), no subscription. Turning the model around in 3D and changing its numbers in the viewer are free; each AI request (a new part or a chat edit) spends 2 credits, whichever model answers; a download spends 10 credits (+5 for G-code sliced for your printer without Pro or Unlimited); small fixes after a download re-download free.
Questions
It depends on the part. For a functional part that has to fit (an enclosure, a bracket, an adapter), use a text-to-CAD tool that writes a parametric model rather than a mesh: every size you give stays exact and the STL is watertight. SpeakCAD works this way and adds an editor built for the phone, G-code sliced for 380+ printers and Fit Check for clearances; Zoo's Text-to-CAD and AdamCAD's CADAM are other text-to-CAD tools. For figurines and organic shapes, a text-to-3D mesh generator such as Meshy or Tripo gives better results.
Not for your own parts here. Free, without a card: the live demo (3 AI edits of a real part, no account) and the 650+ ready-made library models, which open in a free account and resize in the viewer. Describing your own part uses credits: Starter credits: 75 credits for $5 once (50 + 25 free), no subscription. A request spends 2 credits and a download 10 credits, so a typical part with a couple of edits spends about 16 credits. Some mesh generators have free tiers with limits; check their sites.
Yes. Once the part has rendered, pick your printer in the download dialog (380+ printers with their official OrcaSlicer profiles: Bambu Lab, Prusa, Creality, Elegoo, Anycubic and more), a print profile and a filament, and download G-code ready for the printer; Bambu printers get a sliced .gcode.3mf. G-code sliced for your printer is included in Pro and Unlimited and spends 5 extra credits per slice otherwise.
Yes. Describe the part in Portuguese, Spanish, French, German, Italian or English: the sizes are numbers in any language, and the AI usually answers in the language you wrote in. The editor's buttons and menus are in English.
Yes. The mesh is compiled from a CAD program, so it is closed and manifold by construction and measured in millimetres; it opens in PrusaSlicer, Bambu Studio, OrcaSlicer or Cura without repair. The 3MF carries the same geometry.
The first render usually appears within a minute or two: a new part goes to the strongest models, which reason through the geometry, and small edits land in seconds. A typical functional part, with a couple of edits and a dimension check, is a downloaded file in about 10 to 15 minutes.
Yes. SpeakCAD runs in Safari on iPhone and iPad and in Chrome on Android: type the part, watch it render in the same tab, and the STL, 3MF or G-code lands in Files or Downloads. Nothing to install.
Read more
From a ChatGPT description to a fileThe assistant already wrote the spec or the OpenSCAD: paste it as it is.Edit an STL you already haveResize a download, add a hole, a lid or a mount.The best AI CAD tools for 3D printingText-to-CAD and text-to-3D tools side by side.Text to STL: how AI CAD actually worksFrom the sentence to the program to the mesh.G-code for your printer380+ printers with their official slicing profiles, no slicer to install.