Runs locally
Everything happens on your PC. No upload step, no waiting on a server, no "service unavailable" the night before a print.
Free & open source · Version 0.1.0 for Windows
Design 3D-printable parts
on your own computer.
ScottiCAD is a friendly, hands-on 3D modeller for makers. Drag shapes onto a workplane, pull handles to size them, turn some into holes, and group them into a finished part. When you're done, export a clean, watertight STL for your slicer. It's one small Windows program: no account, no browser, and no cloud.
- No sign-up
- Works offline
- Your files stay on your disk
- Apache-2.0 licensed
Real-time, unedited: building a part in ScottiCAD from first shape to finished design.
57built-in shapes and parametric parts
1file to run: no installer, no runtime
0accounts, logins, uploads or subscriptions
4export formats: STL, OBJ, GLB and SVG
Why ScottiCAD
The easiest way to make a printable part, without handing your work to a website.
Most people who own a 3D printer don't need a full engineering CAD package. They need a bracket that fits, a box for a circuit board, a replacement knob, a name tag for a niece's bike, or a spacer that's exactly 4.2 mm thick. The fastest way to make those things is the "building blocks" approach: put simple shapes together, cut holes where you need them, and let the computer work out the geometry.
That approach usually lives in a web browser, behind an account, with your designs stored on someone else's server. ScottiCAD brings it home. It's a native Windows application that starts in a moment, uses your graphics card directly, keeps working when the internet doesn't, and saves your designs as ordinary files in folders you choose. Back them up, put them in version control, email them to a friend. They're yours.
Private by design
No telemetry, no sign-in, no cloud library. Your designs never leave your machine unless you send them.
Open source
Apache-2.0 licensed and written in Go. Read the code, build it yourself, fix what bugs you and send it back.
Features
Everything you need to go from idea to print.
If you can stack blocks, you can use ScottiCAD. Here's what's in the box.
A big shape library, ready to drag
Pick a shape from the panel on the right and drag it onto the workplane. As you drag, a ghost of the shape follows the mouse and lands on whatever surface is under the cursor, so stacking a cone on top of a box is a single gesture. Hold C to drop it on the workplane instead.
The basics are all here: box, cylinder, sphere, cone, pyramid, roof, round roof, wedge, half sphere, torus, tube, ring, polygon, paraboloid, icosahedron, star, heart, diamond, dice and more. Every shape has sensible defaults and its own parameters: rounded corners on a box, sides on a cylinder, points on a star, wall thickness on a tube.
- Solid and hole versions of the common shapes
- Parameters update the shape live as you slide them
- Search the library by name
Holes that really cut, and booleans that really work
Any shape can be a Solid or a Hole. Holes are drawn see-through so you can line them up. Select the lot, press Ctrl+G, and ScottiCAD performs a true boolean mesh operation: the holes are carved out and the solids are merged into one part.
The result is a closed, watertight mesh that slicers accept without complaint. ScottiCAD repairs the seams that boolean operations tend to leave behind, and heavy groups are computed in the background on all your CPU cores, so the view never freezes while you work.
Grouping is non-destructive. Ungroup with Ctrl+Shift+G and you get your original shapes back, even after saving and reopening the file. Need to keep parts together without merging them? A Bundle group (Ctrl+B) moves them as one but keeps them separate.
Drag the slider to compare the parts before and after grouping.
Before
After
3D text in any font on your PC
Drop a Text shape, type your words, and pick a font. ScottiCAD reads the TrueType and OpenType fonts already installed in Windows, so the font list is as long as yours. Letters are turned into proper solid geometry, with adjustable height and optional bevel.
Raise text for embossed labels, or switch it to a hole for engraved serial numbers, logos, and the name on the bottom of a part so you remember which version it was.
- Every installed font, plus built-in Sans, Serif, Mono and Script
- Text is editable at any time: it's a shape, not a frozen mesh
- Works as a solid or a hole, like any other shape
Freehand when you want it, exact when you need it
Every handle shows its dimension while you drag. Click any number to type an exact value, and press Tab to move between fields. Black corner handles resize, the white ones stretch a single side, the cone on top lifts the part off the workplane, and the curved arrows rotate it with a protractor that snaps to 22.5° on the ring, 1° inside it, or 45° with Shift.
Drop the Ruler anywhere to see a shape's distance from it and its full size in every direction, then type the numbers you want. The Measure tool reads the distance between any two points. Work in millimetres or inches, with a snap grid from fine to coarse.
- Type exact position, size and rotation for any shape
- Metric and imperial units, adjustable snap grid
- Ruler, measure pins and a custom workplane on any face
Line things up without a calculator
Select a few shapes and press L to Align. Dots appear along each axis; hover one to preview the result as a ghost, click to apply. Centring a hole in a box takes two clicks. Mirror (M) flips a shape across any axis the same way.
Cruise (C) lets shapes slide over the surfaces of other shapes as you move them. Drop (D) settles anything floating back down. The Workplane tool (W) puts a new workplane on the face of any shape, even a rotated one, so you can build at an angle as easily as on the flat.
Parametric parts for real projects
Beyond the basic shapes, ScottiCAD ships with a set of practical, adjustable parts for people who build things. Set a few numbers and get a correct part, instead of modelling it from scratch every time.
- Project box with lid, wall thickness and rounded corners
- PCB standoffs with flange and screw hole
- ISO metric threads, hex bolts and hex nuts
- Nut traps, countersunk and counterbored holes
- Spur gears and matching gear racks
- Print-in-place hinges with clearance control
- Knurled knobs with round or D-shaft bores
- Springs, pipe elbows, vent grilles, rounded plates
And for diagrams and dioramas, a set of tech icons: laptop, monitor, keyboard, server, rack, router, switch, cloud, database, Wi-Fi, laser printer and 3D printer.
Import STL, OBJ and SVG
Bring in meshes from anywhere, or drag a file straight onto the window. SVG outlines are extruded into solid shapes, which makes logos and laser-cut drawings easy to reuse.
Export STL, OBJ, GLB and SVG
Export everything or just the selection. STL and OBJ for printing, binary glTF for the web and game engines, and an SVG outline for laser cutters.
Unlimited undo
Every step can be undone and redone, and undo puts your selection back the way it was. Experiment freely.
Colours and transparency
A full colour picker with presets and hex entry, multicolour groups that keep each part's colour, and see-through shapes for checking what's inside.
Hide, lock and annotate
Hide shapes to get them out of the way, lock finished parts so they can't be bumped, and pin notes to shapes to remind yourself why that hole is 3.4 mm.
Copy, paste, duplicate
Paste in place, or duplicate and move: ScottiCAD remembers the step and repeats it, which makes rows of holes and arrays of pegs quick.
View cube and orthographic view
Orbit with the right mouse button, pan with the middle, zoom to the cursor. Click the view cube for a straight-on view, or switch to orthographic for true proportions.
Printer bed presets
Set the workplane to the size of your printer's bed so you can see at a glance whether the part fits.
Plain, open file format
Designs are saved as readable JSON .scotticad files that keep the full group tree, so nothing
is flattened and every step stays editable.
How it works
Four steps from blank workplane to finished print.
-
Drag in shapes
Pick boxes, cylinders, text and parts from the library and drop them on the workplane.
-
Size and place
Pull handles or type exact numbers. Rotate, lift, align and mirror until it's right.
-
Cut holes and group
Turn shapes into holes, select everything and group. ScottiCAD does the boolean maths.
-
Export and print
Save a watertight STL, open it in your slicer, and print. That's it.
For tinkerers who code
Everything you can click, you can script.
ScottiCAD has a built-in automation API. Start it with --api and it listens for JSON-RPC on a local
port; every action in the interface is available as a named command, from adding a shape to clicking a toolbar
button. The GUI and the API use the same command layer, so a script sees exactly what you'd see on screen.
A small Python client comes with the source. Use it to generate families of parts from a spreadsheet, batch-export a folder of designs, build test fixtures, or drive the app headless and take screenshots. In fact, every still image on this page was rendered that way.
- Create, move, resize, rotate, align, group, export
- Query the document, bounding boxes and mesh statistics
- Headless mode with PNG screenshots for automated tests
- Simulated mouse and keyboard input for end-to-end testing
# A mounting plate with a centred hole, scripted.
from scotticad import launch
with launch(headless=True) as cad:
plate = cad.add_shape("box")
cad.select([plate])
cad.set_size(80, 50, 4)
hole = cad.add_shape("cylinder", hole=True)
cad.select([plate, hole])
cad.align("x", "center")
cad.align("y", "center")
cad.group("union")
cad.export("plate.stl")
cad.screenshot("plate.png")Under the hood
Small, fast, and built to stay out of your way.
ScottiCAD is written from scratch in Go, with no browser engine and no heavyweight framework underneath.
Hardware-accelerated graphics
The 3D view and the entire interface are drawn with OpenGL 3.3 on your GPU, with multi-sample anti-aliasing, soft shadows and pixel-exact picking of shapes and handles.
Idle means idle
The screen only redraws when something changes. When you're thinking, ScottiCAD isn't using your CPU or spinning your fans.
Parallel boolean engine
BSP-tree constructive solid geometry with seam repair, result caching and multi-core evaluation. Large designs open in seconds, and the view stays responsive while groups are computed.
A single executable
No installer, no runtime to install, no DLLs to chase. Put scotticad.exe in a folder, or on a USB
stick, and run it.
Crisp on any display
Per-monitor DPI awareness keeps text and icons sharp on high-resolution laptops and when you drag the window between screens.
Tested end to end
A Go test suite covers the geometry and document model, and Python tests drive the real application through its API, checking that exported parts are closed and correct.
Keyboard shortcuts
Fast hands, fewer clicks.
Every tool has a key. Here are the ones you'll reach for most. Press F1 in the app for the full list.
Editing
- Ctrl+Z
- Undo
- Ctrl+Y
- Redo
- Ctrl+C / X / V
- Copy, cut, paste
- Ctrl+Shift+V
- Paste in place
- Ctrl+D
- Duplicate
- Ctrl+A
- Select all
- Delete
- Delete selection
Shapes and groups
- H
- Make hole
- S
- Make solid
- Ctrl+G
- Union group
- Ctrl+B
- Bundle group
- Ctrl+Shift+G
- Ungroup
- Ctrl+L
- Lock / unlock
- Ctrl+T
- Transparent
Tools
- L
- Align
- M
- Mirror
- C
- Cruise
- D
- Drop to workplane
- W
- Workplane tool
- R
- Ruler
- N
- Notes
View and files
- F
- Fit all in view
- + / −
- Zoom in / out
- Ctrl+H
- Hide selected
- Ctrl+Shift+H
- Show all
- Ctrl+S / O
- Save, open
- Ctrl+I
- Import
- Ctrl+E
- Export
Get ScottiCAD
Free and open source under the Apache 2.0 licence. Version 0.1.0.
Download for WindowsFrom GitHub Releases. One file, about 5 MB.
Getting started
- Download
scotticad.exefrom the latest release. - Put it in any folder you like and double-click it. There's nothing to install.
- Windows SmartScreen may ask you to confirm the first time, because the program is new. Choose More info, then Run anyway.
- Drag a shape onto the workplane and start building.
Build it from source
With Go installed:
go install github.com/scotticad/scotticad/cmd/scotticad@latestSystem requirements
- Windows 10 or Windows 11, 64-bit
- A graphics card or integrated GPU with OpenGL 3.3 (almost any PC from the last decade)
- A mouse with a right button and scroll wheel is recommended
FAQ
Questions, answered.
Is ScottiCAD really free?
Yes. ScottiCAD is open-source software under the Apache License 2.0. You can use it for personal or commercial projects, read the code, modify it and share it. There's no paid tier, no trial period and no ads.
Does it need an internet connection?
No. Once you've downloaded it, ScottiCAD runs entirely on your computer. It doesn't sign you in, sync anything or phone home. Use it on a plane, in a workshop with no Wi-Fi, or on a machine that's never been online.
Where are my designs saved?
Wherever you choose. Designs are ordinary .scotticad files on your disk, stored as readable JSON that
keeps every shape, group and setting. Because they're plain files, you can back them up, keep them in Git or
share them however you like.
Will the STL files work with my slicer?
They should. ScottiCAD's boolean engine checks and repairs its output so that exported meshes are closed and watertight, which is what slicers such as PrusaSlicer, Cura, OrcaSlicer and Bambu Studio expect. If you find a design that doesn't export cleanly, please open an issue on GitHub with the file attached.
Is it for beginners or experts?
Both. If you've never used 3D software, the drag-and-drop approach is the gentlest place to start: there are no sketches, constraints or feature trees to learn. If you're experienced, you'll appreciate typed dimensions, keyboard shortcuts, parametric parts and a scripting API for repetitive jobs.
Can I open files from other programs?
You can import STL and OBJ meshes and SVG drawings, and combine them with ScottiCAD shapes, including cutting holes into imported meshes. Imported meshes become shapes you can move, scale, colour and group like any other.
Does it run on macOS or Linux?
Not yet. ScottiCAD is a native Windows application. It's written in Go and draws with OpenGL, so other platforms are possible in the future, but Windows is the focus for now.
Is this a mature product?
ScottiCAD is young: version 0.1.0 is its first public release, and it's under active development. Expect rough edges, and please report the ones you find.
How can I help?
Use it, tell people about it, and report bugs and ideas on the GitHub issue tracker. Pull requests are welcome too: new parametric parts are a great first contribution.
Your next part starts with a single shape.
Download ScottiCAD and put something on the workplane.