Design a 3D-printable bracket, box or mount with an AI CAD agent
How the Makerful CAD agent turns a sentence with millimetres into a parametric OpenSCAD part with sliders, and exports STL or STEP. Try it free.
By Geehwan, Founder, Makerful · November 10, 2026 · 3 min read
Mesh generators are great for figures and terrible for parts. If the thing has to fit something, you need real geometry with real numbers. That is what the CAD door of Makerful is for, and this is how I use it.
What the CAD agent is
It is a chat that writes and runs OpenSCAD, the script-based CAD program, and shows you the result in a 3D viewer. You describe the part with dimensions; it produces a parametric design where the key numbers are sliders, so "make it 5 mm wider" is a drag, not a redo. Every design exports as STL or 3MF for printing and STEP for other CAD tools.
Because the output is code, the geometry is exact: holes are circles of the diameter you asked for, walls are the thickness you set, and the model is watertight by construction.
A prompt that works
Give it the job, the dimensions that matter, and how it will be printed. For example:
"A wall hook for a 25 mm wide strap. Back plate 60 × 40 × 4 mm with two countersunk holes for M4 screws, 40 mm apart. Hook sticks out 35 mm with a 3 mm lip. Print it flat on the back."
From that, the agent builds the plate, the holes with the countersink, the hook profile, and exposes plate size, hole spacing and hook reach as sliders. The first design in a session is 30 credits; moving the sliders is free.
What it is good at
- Mounts and brackets with screw holes on a known pitch.
- Boxes and organisers sized to the thing inside, with snap or friction lids (there is a box-with-lid recipe).
- Spacers, adapters and replacement knobs where you can measure the original.
- Stands and holders for phones, controllers, tools.
- Gears and simple mechanisms, within reason.
What to leave to mesh models
Organic shapes: characters, animals, sculpted decor. OpenSCAD can do them but the result looks engineered. Use the 3D door for those and the CAD door for the base, mount or box they sit in; the Studio can combine both in one project.
From a sketch or a broken part
Upload a photo of the broken part or a napkin sketch with the numbers written on it. The agent reads the picture, asks for any dimension it cannot see, and builds from there. It will not measure a photo for you (nothing can, reliably), so have the callipers ready.
Printing tips the agent follows
- Flat faces down, no overhangs beyond 45° where it can avoid them.
- Wall thickness of at least 1.2 mm for PLA at a 0.4 mm nozzle; it will warn you below that.
- Hole diameters are nominal; add 0.2–0.3 mm for a free fit, which you can type in as a tolerance.
Frequently asked questions
Does it export STEP?
Yes, STEP for Fusion, FreeCAD and SolidWorks, plus STL and 3MF for slicers.
Can I edit the OpenSCAD code myself?
Yes. The code is yours to download and the sliders map to its top-level variables.
How accurate are the dimensions?
Exact to what you typed. Print accuracy then depends on your printer; a calibrated FDM printer holds about ±0.1–0.2 mm.
How much does a CAD design cost?
30 credits for the first design in a session; slider changes are free, and a new account starts with 80 free credits.