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Online CAD for 3D printing
Online CAD for people who print, not people who do CAD
SpeakCAD is the easiest way to design a part with real dimensions on your phone: shape it with simple tools or describe it to the AI, and download a print-ready STL, 3MF or G-code sliced for your printer. The hand tools (a hole, a cut, an added tab, an extruded face, rounded corners, a measurement, every size and position in millimetres you type) are free, with or without an account. The AI is there for the rest.How it works
A part in four taps, or one sentence
A new model starts from a sentence, from a starter shape offered in its empty editor (a box, a plate, a cylinder, a tray), or from your own STL or 3MF uploaded there or handed over with no change typed. From there you tap a face and pick a tool, or you type what you need and the AI writes the part. Both end in the same file.2
Tap a face, pick a tool, type the numbers
Hole (with M2 to M8 clearance presets), Cut (a rectangle, a circle or a slot), Add (a tab or a boss), Extrude (a whole flat face pulled out or pushed in), Round (the corners of the part; a pocket you cut by hand gets its own corner radius) and Measure. A hole, a cut or an added shape is placed by typing its centre's distance from the face's edges. Each one compiles in the browser in about a second, and every op is a numbered version you can undo.3
Ask the AI for what the tools cannot do
Round just this edge, hollow it, move the lid, build it from a photo and a ruler: one request (2 credits, up to 10 on a very large model). The AI reads your hand edits as part of the model and keeps them.4
Download STL, 3MF or G-code
A part started from a shape or your own file and shaped by hand downloads free with a free account. A download of a model with AI work spends 4 credits, and small fixes re-download free. G-code sliced for one of 380+ printers spends 5 more unless you are on Pro or Unlimited.The six tools in SpeakCAD, Tinkercad and Onshape
| SpeakCAD | Tinkercad / Onshape | |
|---|---|---|
| Hole | Tap a face, pick a diameter (M2 to M8 presets, or any number), through or to a depth. Free. | Tinkercad: subtract a dragged shape, size typed per shape, aligned by hand. Onshape: sketch a circle on the face, constrain it, extrude a cut. |
| Cut | A rectangle, a circle or a slot with a corner radius, through or to a depth, where you tapped. Free. | Tinkercad: the same subtracted shapes. Onshape: sketch and extrude-remove, with full constraints. |
| Add | A tab or a boss of the size you type, standing on the face you tapped. Free. | Tinkercad: drag a new shape and align it. Onshape: sketch and extrude. |
| Extrude | Tap a flat face, choose Pull out or Push in, type the Distance: the whole face moves. Free. | Tinkercad: no face to pull; resize the shape, or stack or subtract another one. Onshape: extrude or move a face, adding or removing material. |
| Position | A hole, a cut or a tab: type its centre's distance from the face's edges (Centre 12 mm from the left edge), or Centre on the face. Before Apply or later on its card. Free. | Tinkercad: drag, or type a position with the ruler. Onshape: sketch dimensions and constraints. |
| Rounded corners | The corners of a part, radius you choose (a pocket you cut by hand gets its own corner radius); a single edge is an AI request. Free. | Tinkercad: no fillet tool; people build rounded shapes from cylinders. Onshape: fillets on the edges you pick (Parasolid kernel). |
| Measure | Two taps: the distance, its X, Y and Z parts, and the tapped face's size and thickness. Free. | Tinkercad: the ruler shape. Onshape: a measure tool. |
| Dimensions | Every number is a millimetre value you type. A starter's sizes and the AI's are named numbers: change one later and the part rebuilds. A hand edit stays where you placed it, its position a number like its size. | Tinkercad: size fields per shape, not linked to each other. Onshape: full sketch constraints and dimensions. |
| On a phone | Yes: the editor is laid out for a thumb, tools in a bottom sheet, in Safari or Chrome. | Tinkercad: no, phones are unsupported and the window must be at least 864 px wide. Onshape: iOS and Android apps, which reviewers find very hard to use on a phone. |
| AI | Describe the part or the change in plain words; the AI writes the model and keeps your hand edits. | Tinkercad: none. Onshape: AI Advisor answers questions about Onshape; it does not see your model or make geometry (agents announced). |
| Files | STL, 3MF, or G-code sliced for 380+ printers. No STEP: the output is a mesh. | Tinkercad: STL, OBJ, GLTF, SVG. Onshape: STEP, STL, 3MF and more. |
| Free tier | Hand tools and the files they make; the live demo (3 AI edits, no account); 650+ ready-made library models. AI requests, downloads of AI work and G-code use credits (Maker is $7.99 a month for 60 credits). | Tinkercad: fully free. Onshape: a free plan for non-commercial use, where every document is public. |
HoleSpeakCAD: Tap a face, pick a diameter (M2 to M8 presets, or any number), through or to a depth. Free.Tinkercad / Onshape: Tinkercad: subtract a dragged shape, size typed per shape, aligned by hand. Onshape: sketch a circle on the face, constrain it, extrude a cut.
CutSpeakCAD: A rectangle, a circle or a slot with a corner radius, through or to a depth, where you tapped. Free.Tinkercad / Onshape: Tinkercad: the same subtracted shapes. Onshape: sketch and extrude-remove, with full constraints.
AddSpeakCAD: A tab or a boss of the size you type, standing on the face you tapped. Free.Tinkercad / Onshape: Tinkercad: drag a new shape and align it. Onshape: sketch and extrude.
ExtrudeSpeakCAD: Tap a flat face, choose Pull out or Push in, type the Distance: the whole face moves. Free.Tinkercad / Onshape: Tinkercad: no face to pull; resize the shape, or stack or subtract another one. Onshape: extrude or move a face, adding or removing material.
PositionSpeakCAD: A hole, a cut or a tab: type its centre's distance from the face's edges (Centre 12 mm from the left edge), or Centre on the face. Before Apply or later on its card. Free.Tinkercad / Onshape: Tinkercad: drag, or type a position with the ruler. Onshape: sketch dimensions and constraints.
Rounded cornersSpeakCAD: The corners of a part, radius you choose (a pocket you cut by hand gets its own corner radius); a single edge is an AI request. Free.Tinkercad / Onshape: Tinkercad: no fillet tool; people build rounded shapes from cylinders. Onshape: fillets on the edges you pick (Parasolid kernel).
MeasureSpeakCAD: Two taps: the distance, its X, Y and Z parts, and the tapped face's size and thickness. Free.Tinkercad / Onshape: Tinkercad: the ruler shape. Onshape: a measure tool.
DimensionsSpeakCAD: Every number is a millimetre value you type. A starter's sizes and the AI's are named numbers: change one later and the part rebuilds. A hand edit stays where you placed it, its position a number like its size.Tinkercad / Onshape: Tinkercad: size fields per shape, not linked to each other. Onshape: full sketch constraints and dimensions.
On a phoneSpeakCAD: Yes: the editor is laid out for a thumb, tools in a bottom sheet, in Safari or Chrome.Tinkercad / Onshape: Tinkercad: no, phones are unsupported and the window must be at least 864 px wide. Onshape: iOS and Android apps, which reviewers find very hard to use on a phone.
AISpeakCAD: Describe the part or the change in plain words; the AI writes the model and keeps your hand edits.Tinkercad / Onshape: Tinkercad: none. Onshape: AI Advisor answers questions about Onshape; it does not see your model or make geometry (agents announced).
FilesSpeakCAD: STL, 3MF, or G-code sliced for 380+ printers. No STEP: the output is a mesh.Tinkercad / Onshape: Tinkercad: STL, OBJ, GLTF, SVG. Onshape: STEP, STL, 3MF and more.
Free tierSpeakCAD: Hand tools and the files they make; the live demo (3 AI edits, no account); 650+ ready-made library models. AI requests, downloads of AI work and G-code use credits (Maker is $7.99 a month for 60 credits).Tinkercad / Onshape: Tinkercad: fully free. Onshape: a free plan for non-commercial use, where every document is public.
What "online CAD" means here
SpeakCAD runs in the browser, on a phone as well as on a computer, and makes solid parts for a 3D printer. It is not a general CAD program: there is no sketch plane, no constraint solver and no STEP export. There are six tools that cover what most printed parts need (a hole where you tap, a cut, an added tab, an extruded face, rounded corners, a measurement), every size and position in millimetres you type, and an AI you can describe the rest to. The file that comes out is a watertight STL or 3MF, or G-code already sliced for your printer.
The hand tools
- Hole. Tap a face, pick a diameter. Presets for M2 to M8 clearance holes, a tap toggle for threaded holes, "through" or a depth.
- Cut. A rectangle, a circle or a slot, with a corner radius, through or to a depth, where you tapped.
- Add. A tab or a boss of the size you type, standing on the face you tapped. Use it for a mounting tab, a stand-off, a stop.
- Extrude. Extrude pulls a whole flat face out, or pushes it in, by the distance you type; a curved face is an AI request. Use it to make a plate thicker, a wall taller or a pocket deeper without touching the rest.
- Round. Round rounds the corners of a part: the edges parallel to the normal of the face you tapped (a pocket you cut by hand gets its own corner radius). Rounding a single edge, or the top edges of a box, is an AI request. On your own STL or 3MF opened with no AI turn, the whole file is one part, so Round rounds the corners of its outline seen from the face you tapped: right for a boxy part, and refused when the radius would take off more than the corners.
- Measure. Two taps give the distance and its X, Y and Z parts; one tap shows the face's size and the wall thickness under it.
A hole, a cut or an added shape lands where you tap, and its Position rows set its centre in millimetres from the face's edges (Centre 12 mm from the left edge), before you apply it or later on its card. "Centre on the face" puts it in the middle.
Each tool compiles in the browser in about a second and becomes a numbered version with undo and a ghost of what changed. Nothing is sent to a server to do it, and nothing is charged.
Where the AI comes in
Some things are quicker to say than to tap, and some the tools do not do: round a single edge, hollow a shape, move a lid, add a snap fit, copy a part from a photo and a ruler, or build the whole part from a sentence. That is a request to the AI, and it reads your hand edits as part of the model, so they stay where you put them. Shaping a part by hand (a hole, a cut, an added tab, an extruded face, rounded corners) and downloading what you shaped are free. Each AI request spends 2 credits, a download of AI work 4 credits, and G-code 5 more.
Starting points
A new model opens on an empty editor that offers the four starter shapes (a box, a plate, a cylinder or a tray, with their sizes in millimetres) and an upload, with the chat beside it to describe the part instead. You can also bring an STL or 3MF you downloaded. It opens as a model with no AI turn, ready for the hand tools, when you upload it with the Upload an STL or 3MF card in a new model's empty editor, drop it on the Edit an STL box with the change left empty, on the online slicer and press Change it with AI with nothing typed, or on SpeakCAD's card in ChatGPT or Claude with no change; type a change with it instead and that is one AI request. Or open one of the 650+ ready-made library models and change its numbers.
SpeakCAD, Tinkercad or Onshape
Tinkercad is free and the friendliest way to learn CAD by dragging blocks, and it is the right choice for a classroom. It has no fillet tool, its size fields are not linked to each other, and it does not run on a phone. Onshape is professional browser CAD with a free plan: sketches, constraints, fillets on the edges you pick and STEP, at the price of a real learning curve and public documents on the free plan. SpeakCAD sits between them for one job: a dimensioned part for a printer, shaped by hand or described, on the phone in your pocket, with the file sliced for your printer at the end. FreeCAD and SketchUp Free are compared the same way, and all comparisons are in one table.
What it costs
Shaping a part by hand (a hole, a cut, an added tab, an extruded face, rounded corners) and downloading what you shaped are free. Each AI request spends 2 credits, a download of AI work 4 credits, and G-code 5 more. Plans: Maker $7.99 a month for 60 credits, Pro $14.99 with G-code included, Unlimited $39.99. No free trial of the AI; the free things are the hand tools, their files, the live demo and the library. See pricing.
Questions
Yes for the hand tools and the files they make. AI requests, downloads of AI work and G-code use credits. Shaping a part by hand (a hole, a cut, an added tab, an extruded face, rounded corners) and downloading what you shaped are free. Each AI request spends 2 credits, a download of AI work 4 credits, and G-code 5 more. The live demo (3 AI edits of a real part) needs no account; a download needs a free account.
Yes. SpeakCAD runs in Safari on iPhone and iPad and in Chrome on Android. The tools sit in a bottom sheet above the chat, every number is typed with the keyboard, and the STL, 3MF or G-code lands in Files or Downloads. Nothing to install.
Round rounds the corners of a part: the edges parallel to the normal of the face you tapped (a pocket you cut by hand gets its own corner radius). Rounding a single edge, or the top edges of a box, is an AI request. The AI builds the rounded shape into the model, and your hand edits stay where they were.
Not for the six tools: you tap a face and type millimetres, for sizes and for the distance from the face's edges, with M-size presets for holes and "through" for depths. And when you would rather not draw at all, describe the part to the AI: no CAD skills needed for that either, only the measurements.
STL and 3MF, watertight and in millimetres, and G-code sliced with the official profile of one of 380+ printers. Not STEP: the model is a mesh compiled from a program, so for a part a machinist will cut, use Onshape or FreeCAD.
Read more
A Tinkercad alternative with real dimensionsRounded corners, linked millimetres and a phone editor; where Tinkercad still wins.SpeakCAD vs OnshapeProfessional browser CAD with a free plan, against a print-ready part from a phone.SpeakCAD vs FreeCADFree desktop CAD that does everything, against six tools and an AI in the browser.Shape a part by hand: the guideHole, cut, add, extrude, round and measure, one by one, with the numbers and positions to type.Edit an STL you downloadedAdd a hole, a cut or a tab to a Thingiverse or Printables model, or describe the change.Text to STL with AIWhen you would rather describe the whole part than shape it.Online slicerAlready have the file? Slice it for your printer in the browser.PricingWhat is free, what spends credits, and the three plans.All comparisonsTinkercad, Onshape, FreeCAD, SketchUp, Fusion 360, Shapr3D and the AI tools in one table.