Writing effective prompts
The AI turns natural language into parametric CAD. The clearer and more specific your request, the closer the first result. Name the base shape, give real dimensions with units, and describe features relative to faces or edges you can point to.
Think of it like briefing a machinist: state the overall size, then the features. You can always refine afterward, so start with the shape that gets you 80% of the way there.
- Include units — 50 mm, 2 in — so nothing is ambiguous.
- Anchor features to references: on the top face, centered, 10 mm from the left edge.
- Ask for one clear change at a time when refining, rather than a paragraph of edits.
Tip: Vague in, vague out. Add a bracket 80 mm long is weaker than a 80 x 40 x 6 mm mounting bracket with two 6 mm bolt holes 60 mm apart.
Voice input
Voice is a first-class input, not an afterthought. Tap the microphone in the chat panel and talk through the change you want — HelioCad transcribes it and treats it exactly like a typed prompt.
Voice shines at the bench and during hands-busy work: dictate a dimension change or a new feature without breaking focus on the model.
Image-to-model
Drop in a photo, a napkin sketch, or a reference image and HelioCad will interpret it and build a parametric solid you can edit. This is the fastest path from a real-world object or a hand drawing to editable CAD.
Image-to-model is opt-in per image, so you stay in control of when a picture is turned into geometry. Provide a straight-on view and any known dimensions in the same message for the most accurate rebuild.
Tip: Pair the image with a dimension or two in the same prompt — for example, upload a photo and add the outer diameter is 40 mm — to anchor the scale.
Iterative refinement
Modeling with the AI is a conversation. After the first result, send follow-up messages to dial in dimensions, add fillets and chamfers, reposition features, or change the overall proportions. HelioCad keeps the model parametric, so each refinement edits the underlying feature rather than starting over.
Because every AI change lands in the feature timeline, you can review exactly what it did, edit that step by hand, or roll it back if it went the wrong way.
- Refine one thing per message for predictable results.
- Reference earlier features by name — thicken the wall, enlarge the counterbore.
- Undo is always available; nothing the AI does is destructive.
Reading and editing the generated code
HelioCad models are backed by real parametric CAD code. You can open the generated code for any feature to see exactly how the geometry was built, learn the underlying operations, and make precise edits that would be tedious to describe in words.
This makes the AI transparent rather than a black box: the chat proposes code, executes it, and shows you the result — and you can always take the wheel.
Ready to try it yourself?
Everything in this guide works in your browser — no install required. Start a free trial and build your first part.