A typical AI 3D tool
- Generate the base mesh20 credits
- Add color and texture10 credits
- Clean up the mesh5 credits
One finished model$0.70 to $0.84
And a credit is worth a different amount on every plan.
CAD for 3D printing,
without learning CAD.
Fusion 360 and OpenSCAD take weeks before your first usable part. Describe what you need instead and get a print-ready 3D file with real dimensions and tolerances.
Start Free - No Credit Card Required
+1k
Loved by 2,000+ makers4,500+ models generated
Thinking...
The learning curve
The part is simple. Traditional CAD is not.
You need a bracket with the right hole spacing, an enclosure that fits a known board, a replacement clip. The geometry is trivial, but sketches, constraints, extrudes, and fillets stand between you and a printable file. Most makers give up before the first print.
So we removed the software. You describe the part. The AI compiles it, to real millimetres.
How it works
Describe it, tune it, print it
- 1
Describe the part
Say what it is, the dimensions, the hardware it must fit.
- 2
Tune every dimension
Every measurement becomes a slider, and tweaking is free.
- 3
Download and slice
A slicer-ready 3MF or STL, 1:1 in Bambu Studio or Prusa.
Real measurements
Built in actual millimetres
Ask for a case that fits a specific board and it looks up the spec, lays out mounting standoffs and connector cutouts, and shows the dimensions right on the model before you download.
- Looks up real part specs, not rough guesses
- Dimensions shown on the model in the viewer
- Tolerances tuned for FDM so holes and fits print true
One tool, the whole job
No stack of apps to stitch together
Modeling, editing, mesh repair, and export usually mean three or four programs. GrandpaCAD does the whole job in one chat, and checks its own work before it hands you the file.
- Model, refine, and export without switching tools
- It repairs and validates the mesh automatically
- Bring an existing STL or 3MF and change it in place
Pick the path that fits how much time you have
Traditional CAD software is powerful and worth learning if you'll use it every week. If you just need the part, there's a faster road.
 GrandpaCAD | Fusion 360 | Tinkercad | OpenSCAD | |
|---|---|---|---|---|
| Time to first part | 60 seconds | 40+ hours to learn | A few hours | Learn to code |
| Precise dimensions | Yes, to the mm | Yes | Rough | Yes |
| Organic shapes | Yes | Hard | No | Very hard |
| Cost | From $0.34/part | $60+/mo | Free | Free |
One toolbox for every 3D modeling job, all in one chat.
- Describe it, get a real modelA phone stand tilted 15°
- Exact measurements that stickM5 bolt, 32 mm spacing
- Sculpt organic shapesA coiled dragon
- Precise and artistic, fusedNewDragon on a measured base
- Turn a photo or sketch into a part
- Engrave names and patternsEngrave a name on the lid
- Looks up real part specsNew
- Asks before it guesses
See what makers build without CAD
Open any model in the public library and tell the AI what to change. No account needed to look around.
Loved by makers
2,000+ people making real prints
Unedited feedback from the in-app rating prompt. We only show country to keep makers anonymous.
"generated a printable design on the first try!"
"Fast easy and good quality"
"It's working good. Grandpa!"
"yay so fun"
Pulled from real CSAT survey responses inside the GrandpaCAD app.
Made for My Grandpa
This tool was created for my grandfather who loves 3D printing but struggles with complex modeling software. He doesn't speak English, which makes most 3D design tools inaccessible to him.
Despite these challenges, he's passionate about creating 3D prints for our family. He uses his BambuLab A1 printer and now can easily create custom models by simply describing what he wants.
Read His Story
One generation, one price
You count models, not credits.
Other AI tools bill in credits, so one model becomes a stack of charges at a rate that shifts per plan. We just count whole models, and tweaking is free.
GrandpaCAD
- A complete, colored, print-ready model1 generation
- Tweak any dimension afterwardfree
One finished modelabout $0.34
On a plan. Around $0.48 on a one-off pack. No credit math.
Same quality on every plan.
Every plan generates the same models at the same quality. The difference is how much you generate and how much control you want. Tweaking a finished model with the sliders never counts as a generation.
Free trial
$03 models, no card
Just to get a feel for it. The output is the same quality as every paid plan.
- 3 generations
- Full-quality output
- No credit card
Credit packs
$12+one-off, valid one year
For a single project. A fixed number of generations, no recurring charge.
- Starter $12 · Plus $22 · Pro $45
- Costs more per model than a plan
- Valid for one year
Subscription
$24per month, 26% off yearly
For power users who want the full platform and more generations than they will realistically use.
- 70 generations a month
- Private models, commercial license
- Multiple workspaces and more control
Common questions
What's the easiest CAD software for 3D printing?
For most makers, the easiest CAD is no CAD: describe the part in a chat and let the AI model it. Tinkercad is the easiest traditional option but tops out quickly on precision. Fusion 360 and OpenSCAD are powerful, and both take weeks to get productive in.
Is there free CAD software for 3D printing?
Yes. Tinkercad, OpenSCAD, and FreeCAD are free, and Fusion 360 has a hobbyist license. GrandpaCAD gives you 3 free generations with no credit card, so you can compare the describe-it route against learning a tool before spending anything.
Can it really hit exact dimensions?
Yes. Give dimensions in your message and they land in the model as real millimetres. The AI also looks up specs for known hardware (boards, screws, bearings) and applies FDM-friendly tolerances so printed holes and fits come out true.
What file do I get for my slicer?
A 3MF or STL that loads 1:1 in Bambu Studio, PrusaSlicer, and Orca. OBJ, GLB, and GLTF exports are there too if you need them.
What if the first result isn't right?
You iterate in the same chat: point out what's off and it regenerates. Every dimension is also exposed as a slider, and slider tweaks never cost a generation.
Related guides and tools
- Image to 3D modelStart from a photo or a hand sketch instead of a description.
- 3D modeling for 3D printingA beginner's map of every way to get a printable model.
- OpenSCAD vs CadQuery vs build123dHow the code-CAD tools compare, from the team that runs them all in production.
- The state of AI CADWhere LLM-driven CAD stands today and where it's heading.
- Thread and tap size calculatorLook up metric thread, clearance, and tap drill sizes.
- Free 3D printing toolsThe full library: calculators, converters, viewers, and repair.
Skip the learning curve.
Describe your part.
3 free models, no credit card. GrandpaCAD models it while Fusion is still installing.