AI CAD generators compared

"AI CAD" is used to describe tools that work in completely different ways and produce completely different files. Comparing them by brand is unhelpful, because the thing that determines whether a tool is useful to you is what kind of geometry comes out the other end. There are three broad approaches.

1. Mesh generators (text to 3D)

These produce a triangle mesh directly: a shell of connected facets that approximates a surface. They are impressive at organic and artistic shapes, and they are what most people have seen when they have seen AI 3D generation.

The catch is that a mesh contains no engineering information. There is no such thing as a hole in a mesh, only triangles arranged in a circle. There are no dimensions to edit, no faces to reference, and often no guarantee the surface is even closed. Meshes from generative tools frequently need repair before a slicer will accept them, and no amount of repair turns one into a machinable part.

Good for: renders, concept visuals, game assets, decorative prints. Not for: anything with a tolerance.

2. Script based CAD generation

These write parametric modelling code and execute it against a real CAD kernel. The AI does not produce geometry at all; it produces the instructions, and an established geometry engine builds the solid from them.

Because the kernel does the modelling, the output is a genuine boundary representation solid: real faces, real edges, real named dimensions. It exports as STEP. It opens in other CAD software as an editable part. And because the script is parametric, every driving value stays adjustable after generation.

The trade off is honesty about scope. A kernel will refuse to build geometry that does not make sense, so this approach fails visibly rather than producing something that looks plausible and is not. That is the right failure mode for engineering, and it does mean some prompts need a retry.

Good for: mechanical parts, anything destined for manufacture or a STEP workflow. Not for: sculpted or artistic forms.

This is how TextoCAD works. It is also why every model in the gallery ships with a parameter table and a STEP download rather than just a picture.

3. CAD copilots

These live inside existing CAD software and assist with the work you are already doing: suggesting features, automating repetitive operations, answering questions about the interface. They do not generate parts from a description so much as make an expert faster.

Good for: professionals already fluent in a CAD suite. Not for: people who wanted to avoid learning one.

How to tell which kind you are looking at

The fastest test is the export list. If a tool offers STL, OBJ, and GLB but not STEP, it is a mesh generator regardless of how it describes itself. STEP export requires solid geometry, so its presence is a reliable signal.

The second test is whether you can change a dimension after generating. If the answer is "regenerate with a different prompt", the output is not parametric. If the answer is "move this value", it is.

Which should you use?

If you are making something to look at, use a mesh generator; they are far better at organic form than any CAD approach. If you are making something to build, fit, or manufacture, you need real solid geometry, which means a script based CAD generator or traditional CAD. If you already model professionally and just want to go faster, a copilot in your existing tool will beat both.

Related reading: what is text to CAD, text to CAD vs traditional CAD, and text to CAD for 3D printing if your output is going to a printer.