Concepts
What is text-to-CAD?
Text-to-CAD is the use of AI to turn a written description into a CAD model: a solid with exact faces, edges and dimensions that you can edit, measure and export as STEP. QuantCAD is a text-to-CAD platform that builds B-rep solids on the Open CASCADE kernel.
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What does text-to-CAD produce?
A text-to-CAD tool produces a boundary representation (B-rep) solid. The file stores each surface exactly: a plane as a plane, a hole as a cylinder with an axis and a radius, a freeform shape as a NURBS patch. It also stores the topology, meaning which faces meet along which edges, so the shape is one closed body rather than a loose set of surfaces.
In QuantCAD every part is built this way from the start. You can export it as STEP (AP242, in millimetres) to open it as a solid in SolidWorks, Fusion, Onshape, FreeCAD or another CAD tool, or as STL when you need a mesh for 3D printing.
How is text-to-CAD different from text-to-3D?
Most tools sold as text-to-3D produce meshes: flat triangles arranged in the shape you asked for. A mesh can look identical to a solid on screen. The difference shows up when you measure, edit or manufacture it.
| Aspect | Text-to-CAD | Text-to-3D (mesh) |
|---|---|---|
| Output | B-rep solid | Triangle mesh |
| Faces and edges | Exact planes, cylinders and freeform surfaces | Flat triangles that approximate the surface |
| Edit in a CAD tool | Select faces and edges, fillet, dimension | Needs mesh tools or remodeling |
| Typical formats | STEP, plus STL generated from the solid | STL, OBJ, GLB |
| Typical use | Parts to manufacture, assemblies, CAD handoff | Renders, games, concept visuals |
More detail in Text-to-CAD vs text-to-mesh.
How does text-to-CAD work in QuantCAD?
Describe the part or product
Write what it is, what it does and the dimensions that matter: sizes, wall thickness, hole diameters and spacing, clearances. See Writing Good Prompts.
Build it
Build mode generates the geometry. In manual mode you build an assembly part by part and confirm each step. In auto mode QuantCAD plans the parts and builds the whole assembly in one pass.
Review and iterate
Inspect the model in the 3D viewer. Use Ask mode for questions and Build mode for changes. Every Build creates a new revision you can go back to.
Export
Download STEP for CAD tools or STL for 3D printing.
What can you build with text-to-CAD?
Text-to-CAD works best for geometry you can describe with sizes, holes, fillets and standard features: brackets and mounting plates, enclosures and housings, jigs and fixtures, adapters and holders, and multi-part assemblies such as clamps or product prototypes. See the use cases for example prompts.
What are the limits today?
- • Generated geometry should be checked (dimensions, tolerances and intent) before manufacturing.
- • Vague prompts give generic shapes. Stating the dimensions that matter gives far better results.
- • QuantCAD does not import existing CAD files yet. Every product starts from a prompt.
- • Exports are STEP and STL. Other formats such as IGES are not available yet.
Can a general-purpose AI chat assistant do text-to-CAD?
A general-purpose AI chat assistant can write code for CAD scripting tools such as OpenSCAD or CadQuery. You then run that code in the tool yourself to get a model. Some assistants can also pass a request to a connected 3D generator, which usually returns a mesh. A text-to-CAD platform such as QuantCAD does the modeling itself and gives you the solid, a 3D viewer, revision history and STEP export in one place.
How do you check that a model is real CAD?
Export the STEP file and open it in the CAD tool you use. Click the inside of a round hole: one cylindrical face should highlight. Measure it, apply a fillet to an edge, and look at the face count. A simple bracket has a few dozen faces; thousands means a mesh wrapped in a STEP file.