Text-to-CAD: parametric source, geometry evidence and responsible handoff
Choose STEP, STL, 3MF, GLB or a drawing by the downstream task
Distinguish editable model intent, exact CAD inspection, mesh delivery and drawing workflows without assuming every export retains every capability.
What you will learn
- Choose the representation by what the next tool needs
- Declared exports and one-off conversions have different path rules
- Separate mesh-only work from exact-geometry review
Before you start
- Basic Python functions, modules and file paths
- Understanding of units and the difference between a design and a physical part
Plan a bounded CAD exercise and distinguish source freshness, document inspection, visual review and manufacturing decisions.
Key takeaways
- Choose formats by downstream operations and retained information.
- Decorator and command output paths have different bases.
- Inconsistent sidecar documentation requires targeted verification.
Choose the representation by what the next tool needs
Use the CAD source to change the model’s intended geometry when it exists. STEP supports the CAD inspection workflow; STL, 3MF and native GLB are mesh exports for appropriate downstream tools. DXF has a separate drawing workflow. The best format depends on the requested handoff, not which screenshot looks most attractive.
A mesh render does not restore CAD topology or prove the original source parameters. The snapshot documentation accordingly gives STEP-only capabilities that are absent from mesh snapshot commands. Do not expect a format conversion to preserve every selector, assembly relationship or editing workflow.
Declared exports and one-off conversions have different path rules
The export guide says a relative decorator out path is resolved against the model script, whereas one-off command output paths resolve against the current working directory. That distinction explains files appearing in unexpected folders when the same script is launched from elsewhere.
The core CAD guide and export reference disagree in places about where output declarations live and when a sidecar is present. We do not turn those inconsistent descriptions into a universal rule. For automation depending on sidecar metadata, inspect the installed matching runtime and test the specific output contract first.
Separate mesh-only work from exact-geometry review
The guides explicitly permit a model declaring only mesh outputs, with no STEP file required. Review that artifact using its own format workflow, while keeping any unmeasured design properties visible. For a CAD task with a primary STEP, validate that geometry before treating its exported mesh as the delivered result.
Choose a conventional CAD editor or further engineering review when the required constraints or downstream editability exceed what you can substantiate through the inspected workflow. This series offers format reasoning, not a universal claim that text-driven modeling replaces every established CAD process.
Decision guide
| Criterion | Option A | Option B |
|---|---|---|
| Best when | You need predictable behavior and easy auditing | You need adaptive optimization and have reliable telemetry |
| Main risk | May leave performance on the table | Can become difficult to explain or debug |
Implementation steps
- 1
Identify the required downstream operation.
- 2
Choose source, CAD, mesh or drawing representation.
- 3
Confirm the output path base.
- 4
Test metadata assumptions before integrating automation.
Copy-ready example
{
"formatDecision": true,
"need": "inspect exact CAD geometry",
"primary": "STEP",
"optionalDelivery": "STL",
"decoratorOutBase": "model script",
"commandOutBase": "working directory",
"sidecarContractVerified": false
}Frequently asked questions
Must every model emit STEP?
No. The inspected guides explicitly support mesh-only decorated models.
Are all relative output paths based on the current directory?
No. The export reference distinguishes script-relative decorator outputs from command outputs.
Sources
- Text-to-CAD / skills/cad/SKILL.mdSource checked 2026-09-14
- Text-to-CAD / skills/cad/references/supported-exports.mdSource checked 2026-09-14
- Text-to-CAD / README.mdSource checked 2026-09-14