Text-to-CAD vs traditional CAD

Last Tuesday I modeled a simple mounting bracket in Fusion 360. Two legs, four holes, a couple of fillets, nothing exciting. Took me about twenty minutes, including the two I spent staring at the screen trying to remember if the bolt pattern was 60mm or 65mm. Then I typed roughly the same description into Zoo.dev's text-to-CAD tool and got a bracket back in about thirty seconds. I put the two files side by side on my second monitor, the one with the wobbly stand I keep meaning to replace, and just looked at them.

From three feet away, they looked the same. Up close, they were different objects living in different realities.

The thirty-second version and the twenty-minute version#

The bracket from Zoo.dev had the right general shape. The legs were close to what I asked for. The holes existed. But the fillet radii were not what I specified, the wall thickness varied slightly between legs for no reason, and the hole spacing was off by about 1.5mm. Not visible on screen. Very visible when you try to bolt it to an aluminum extrusion.

The Fusion 360 bracket was exactly what I drew. Every dimension was what I chose. Every feature was where I put it. The feature tree was clean enough that I could go back and change the leg height without the rest of the model throwing a tantrum. Not because Fusion is perfect, it absolutely isn't, but because I built the model with constraints that I understood and controlled.

That comparison is basically the entire text-to-CAD vs traditional CAD conversation, compressed into one bracket and two cups of coffee.

Speed vs control, and why you can't have both yet#

Text-to-CAD is fast. Absurdly fast for simple geometry. You type a description, wait a few seconds, and get a solid body. If you just need a rough shape to check proportions or test a fit, that speed is genuinely valuable. I've used it to knock out quick fixture concepts while waiting for a file to export. It fills dead time well.

Traditional CAD is slow by comparison. You sketch, constrain, extrude, add features one at a time, check your work, and occasionally argue with a fillet that has decided today is the day it develops personal standards. But every minute you spend building the model is a minute the model is learning what you actually want. Constraints capture design intent. Parametric dimensions mean you can change your mind later without starting over. The slowness isn't waste. It's information being embedded into the geometry.

Text-to-CAD gives you speed but skips the intent. You get a shape that approximates your description. What you don't get is the reasoning behind the shape. There are no sketch constraints linking the holes to the edges. No equations tying one dimension to another. No relationships saying "this hole pattern is symmetric about this axis" or "this wall is always 1.5 times the fillet radius." The geometry just is, and if you need to change it, you're either re-prompting from scratch or rebuilding in traditional CAD anyway.

If you want the longer explanation of how text-to-CAD generates geometry and why the output looks the way it does, the text-to-CAD guide covers the technology and tools in detail.

The feature tree problem#

This is where the gap between the two approaches really shows. In traditional CAD, the feature tree is the model. It's the history of decisions you made, in order, with each feature depending on the ones before it. A well-built feature tree is like a recipe: you can adjust one ingredient and the rest adapts. A badly built one is a hostage negotiation, but at least it's your hostage negotiation. You know where the bodies are buried.

Most text-to-CAD output has no usable feature tree. Zoo.dev gives you a STEP file, which imports into Fusion 360 as a dumb solid. No features. No history. No parameters you can tweak. It's geometry, not a model. CADAgent, which runs inside Fusion 360 directly, is better here because it generates actual modeling operations that show up in the timeline. But even then, the feature tree it builds is rarely how a human would have structured it. The dependencies are fragile. Change one sketch and you're more likely to get a cascade of errors than a clean update.

For a part you're going to build once and never touch again, this doesn't matter much. For anything that lives in a project with revisions, where a client changes the bolt spacing or the enclosure needs to be 5mm taller six weeks later, a model without a clean feature tree is a model you'll end up rebuilding.

Accuracy and manufacturing readiness#

I'll be direct about this because it's the part that separates "cool demo" from "useful tool."

Traditional CAD gives you the dimensions you put in. If you draw a 4.2mm hole, you get a 4.2mm hole. You can add tolerances, specify fits, annotate features for GD&T, and export drawings that a machine shop can actually quote from. The geometry is exactly as precise as you make it. No surprises, unless you made a mistake, which is a different problem and at least one that's your fault.

Text-to-CAD gives you dimensions that are approximately what you asked for. Sometimes very close. Sometimes not. I've had holes come back 0.3mm off from what I specified, which is fine for a 3D print and completely unacceptable for a press-fit bushing. There's no tolerance handling. No GD&T awareness. No understanding of whether a feature is functional or decorative. The AI treats a clearance hole and a press-fit bore the same way, which is to say, it treats them both as circles with a number attached.

Sheet metal is another place where text-to-CAD falls apart. A proper sheet metal part in SolidWorks has bend radii, K-factors, relief cuts, and a flat pattern that actually unfolds correctly. Text-to-CAD will give you a shape that looks bent, but ask for the flat pattern and you'll get a blank stare from the software, because the model was never designed with bending in mind.

If you want to understand what text-to-CAD can and can't produce right now, the accuracy and format issues are covered there.

Where text-to-CAD wins#

It's not all bad news. There are real situations where text-to-CAD saves time, and being stubborn about ignoring them would be dishonest.

Concept exploration is the obvious one. When you're early in a design and need to see ten different bracket configurations before committing to one, typing ten prompts is faster than building ten models. The output isn't production-ready, but it doesn't need to be. You're checking proportions, testing ideas, seeing if a shape even makes sense before investing the time to model it properly. I've used this to settle arguments with a colleague about whether a particular mounting approach would even fit in the available space. Beat sketching it on a napkin.

Quick prototyping for 3D printing is another strong case. Additive manufacturing is tolerant of imperfect geometry. If the mesh is watertight and the dimensions are in the right neighborhood, you can print it, hold it in your hand, and decide if the concept is worth refining. I've printed text-to-CAD brackets to test fit against real hardware, and for that purpose they're perfectly fine.

First-draft geometry also has value. Starting from an 80% shape and fixing it is sometimes faster than starting from a blank sketch, especially for simple parts. Not always. But for a mounting plate with a hole pattern, or a basic electronics enclosure, getting the starting point for free is worth something.

People who aren't full-time CAD users benefit the most. A hardware startup founder who needs a rough model to discuss with a manufacturer. A hobbyist who wants a bracket but doesn't want to learn parametric modeling. A mechanical engineer who needs a quick concept model for a design review but doesn't want to spend an hour in Creo for a throwaway part. Text-to-CAD lowers the floor, and that matters.

Where traditional CAD wins#

Everything else. Production parts. Toleranced designs. Assemblies where parts need to fit together with real constraints. Sheet metal. Injection-molded parts with draft angles and gate locations. Weldments. Anything where a machinist, mold maker, or inspector needs to trust the geometry.

Traditional CAD also wins on revision. A parametric model built with proper intent survives changes. A text-to-CAD output doesn't, because there's no intent encoded in it. Change one thing and you're starting the conversation over. In a project with three rounds of client revisions and a last-minute change to the mounting interface, that difference is worth hours.

Complex assemblies are completely out of reach for text-to-CAD right now. Mating conditions, interference checks, motion studies, assembly-level configurations: none of this exists in the text-to-CAD world. If your part lives alone, fine. If it lives in an assembly with forty other components and needs to play nice with all of them, you're in traditional CAD territory, no discussion.

The question of whether AI will replace CAD designers gets asked a lot. The short answer is: not with the current technology, and not for the work that actually requires engineering judgment.

The hybrid workflow that actually makes sense#

The interesting answer isn't "text-to-CAD or traditional CAD." It's both, used for what each does well.

My current approach for appropriate projects: generate a first draft with text-to-CAD, import the STEP file into Fusion 360, and then model it properly. Rebuild the feature tree, fix the dimensions, add the constraints and relationships the AI couldn't know about. The text-to-CAD output serves as a 3D reference, like tracing over a rough sketch. Sometimes it saves ten minutes. Sometimes it saves nothing because the output was too far off to be useful. I don't force it.

The more mature version of this workflow, the one I think we'll see in a couple of years, uses text-to-CAD for initial geometry and AI assistants inside traditional CAD tools for the refinement. Autodesk is heading this direction with Neural CAD. Dassault's AURA and LEO features in SolidWorks 2026 are pointing the same way. The AI CAD workflow is less about replacing the traditional process and more about accelerating the boring parts of it.

For now, text-to-CAD is a fast, imprecise first pass. Traditional CAD is the reliable, slow, detailed finish. Neither one is going away. The engineers who'll be most productive are the ones who stop treating it as a competition and start treating it as a toolbox with more than one tool in it. Though I'll admit, when my Fusion 360 bracket came out perfect on the first try and the AI bracket needed three rounds of edits, the old-fashioned way did feel a little smug.