Free AI CAD: what each tool really gives you for nothing

Free CAD apps, with or without AI

Real CAD you model yourself, free for personal use. AI help is a side feature or missing. The full comparison is in our guide to free CAD software for 3D printing.

• Autodesk Fusion + Assistant: Fusion for personal use: free and non-commercial, 10 active and editable documents, renewable every 3 years, for hobbyists earning under $1,000 a year from it. Assistant: 10 monthly Flex tokens (beta) on Personal; 1 token = 120 AI assists. Non-commercial (under $1,000 a year in revenue), 10 editable documents, and 10 AI tokens a month on Personal. Source: Autodesk help: included Flex tokens, checked 2026-11-08
• Onshape (AI Advisor, FeatureScript MCP): $0, non-commercial, all documents public. Non-commercial, and every document on the free plan is public. Source: Onshape pricing, checked 2026-11-08
• Tinkercad: Free (Autodesk); not re-verified, the site is JS-rendered. No AI generation that we could find. Source: Tinkercad, checked 2026-11-08
• Shapr3D: Basic: 2 projects, low-resolution STL/3MF only. 2 projects and low-resolution STL/3MF only. Source: Shapr3D pricing, checked 2026-11-08

Free AI 3D generators with no sign-up

"Free, no sign-up, unlimited" is the most common way people search for this, and for hosted AI tools it barely exists, because generation costs the vendor GPU time. The honest options are the ones you run yourself. TRELLIS.2 is MIT-licensed and needs no account, but it needs an NVIDIA GPU with at least 24 GB. Source: TRELLIS.2 README, checked 2026-11-08 CADAM runs OpenSCAD in WebAssembly and you can host it yourself. Source: CADAM on GitHub, checked 2026-11-08 Sloyd's text-to-3D page offers 1 free generation a day with no account, for personal use, though its pricing page limits Guest exports to community models. Source: Sloyd: text to 3D, checked 2026-11-08

GrandpaCAD needs an account (no card) for its 3 free generations. Its free browser tools are different: the calculators work without signing up. More on that below.

How to make free credits go further

• Write the whole brief once, with every size in millimetres. A vague first prompt costs a generation to find out what you meant.
• Change sizes with sliders where you can: in GrandpaCAD, moving a slider doesn't use a generation, while a regenerate in a mesh tool costs credits.
• Check the licence before you print for sale: CC BY means credit the vendor, "personal use" means no selling.
• Prototype the critical feature as a small test, not the whole model.

A wall hook for a 30 mm wide strap: hook depth 25 mm, plate 40 x 60 x 4 mm,
two countersunk holes for 4 mm screws 40 mm apart, 45 degree chamfer under the hook so it prints without supports.
Make hook depth, strap width and plate thickness parameters.

What GrandpaCAD gives you free, exactly

As of November 2026, a free GrandpaCAD account gets 3 generations, once, with no card and the same output quality as the paid plans. You can build and preview models in the browser, move sliders as often as you like without spending a generation, and use the same credits from ChatGPT or Claude through its MCP server. You can't download the STL, 3MF or STEP. A credit pack ($12 for 25, $22 for 55, $45 for 125, each valid a year) or a plan unlocks downloads for good, including models you built before paying. Source: GrandpaCAD pricing and FAQ, checked 2026-11-08

Separate from the AI, GrandpaCAD has 67 free tool pages, including 3D file viewers, converters, repair and measuring tools, and 16 printing calculators. They run in your browser and don't upload your file. See the free tools.

When Zoo is the better pick

If you're a professional engineer who needs free exports, Zoo Design Studio's free plan has them: unlimited modelling, $10 a month of AI usage and STEP and STL export, in a full CAD app with a feature tree. On the free plan Zoo trains on your data with no opt-out. Source: Zoo pricing API, checked 2026-11-08