Shack CAD
Shack CAD is a solid modeller for the Mac, made for parts you intend to 3D print. You sketch a profile, turn it into an exact solid, refine it, and export an STL or 3MF file in millimetres for your slicer.
What it is
Shack CAD is a native macOS application. It requires macOS 14 Sonoma or later.
Every body you see is an exact boundary-representation solid, not a mesh. The viewport and the file you export are both tessellated from the same solids. If an operation cannot be built, Shack CAD says so and leaves the model as it was; it does not quietly substitute an approximation.
The modelling viewport is deliberately plain: neutral shading, edges and selection highlights. It is there to show geometry, not to render a product shot.
How you work
- Sketch a closed profile on a construction plane or on a flat face of an existing body.
- Extrude a closed area of that sketch into a new body, or join it to a body, or cut it away.
- Refine edges with fillets and chamfers, hollow a body with shell, and combine bodies with union, subtract and intersect.
- Export the result for printing.
Sketches stay editable. Change a dimension in a sketch and the body built from it is rebuilt.
Units
Shack CAD keeps every dimension in millimetres internally. You can choose to see and type values in other units; that changes the display only and never resizes the model. See Numbers and units.
Free and paid
Modelling, saving and Standard resolution export to STL and 3MF are free. High resolution export is the only paid feature: a one-time purchase that requests a finer tessellation of curved surfaces. It does not change your model's dimensions. See Exporting for printing.
No account is needed to model, open or save.
A note on printing
A closed, correctly wound mesh is necessary for a dependable print, but it is not a guarantee. Your slicer settings, material and printer still decide the result. Shack CAD reports what it measured; it cannot promise how a part will print.
Where to start
- Your first part walks through a plate with a hole, from an empty project to an exported file.
- Guided lessons are built into the app and check each step as you go.
- Keyboard shortcuts lists every menu shortcut.