cadAI

How Does an Open-Source Web CAD Compare with Fusion 360 or Onshape?

Start with the short answer: for light parametric parts, choose an open-source web CAD, and for complex curved surfaces, assemblies, and CAM, choose Fusion 360 or Onshape. The question in Chinese is how an open-source web CAD compares with Fusion 360 and Onshape.

cadAI is a browser-based parametric CAD from Aiglade, for mechanical part modeling, hole drilling, measurement, and export, with the same kernel on desktop, in the browser, and over MCP.

What was compared, and how it was measured

This page compares eight dimensions, with the same scale applied to all three sides: install, parametric modeling, holes and measurement, complex curved surfaces, assembly motion simulation, CAM toolpaths, AI agent drive, and fits. The method is a category comparison. The cadAI side is written from the facts card, and the Fusion 360 and Onshape sides are written as categories — what desktop CAD software usually supports and usually does not support — without targeting any specific version, and without writing version numbers, prices, or scores. Open source here describes where the kernel comes from, not a guarantee of accuracy: accuracy depends on whether the three steps of modeling, measurement, and checking are done properly.

Side by side: eight dimensions in one table

DimensioncadAI (open-source web CAD)Fusion 360 (category)Onshape (category)
InstallOpens in the browser, nothing to installNeeds local software installedOpens in the browser
Parametric modelingYes, a changed parameter moves the part with itYesYes
Holes and measurementS-02 holes and S-04 measurement connectedYesYes
Complex curved surfacesOutside its scopeYesYes
Assembly motion simulationOutside its scopeYesYes
CAM toolpathsOutside its scopeYesYes
AI agent driveMCP interface, an agent can drive modeling directlyUsually not offeredUsually not offered
FitsSimple parts, flanged plates, brackets; size checks before 3D printingComplex curved surfaces, assemblies, CAMComplex curved surfaces, assemblies, collaborative design

The shortfall of cadAI sits in three rows: complex curved surfaces, assemblies, and CAM. The shortfall of Fusion 360 and Onshape sits in size and learning cost.

Where each one falls short

The shortfalls of cadAI are three. First, complex curved surfaces are outside its scope, so a part that carries complex curved surfaces cannot be made. Second, assembly motion simulation is outside its scope, so several parts moving together, with motion simulation, cannot be done. Third, CAM toolpaths are outside its scope, a model cannot go straight to production work, and every export needs a hand check of dimensions and tolerances first. Two more points belong here: chamfering is not among the five connected intents, and whether it is supported depends on what the page itself offers, and work needing vendor certification and production-grade accuracy sign-off does not fit.

The shortfalls of Fusion 360 as a category are three as well. First, it needs local software installed, it is large, and changing computers means installing it again. Second, the learning cost is high: full features mean a slow start. Third, AI agent drive is usually not offered, and one-sentence modeling is usually not offered either. Onshape as a category is a web version, but it is still a heavy tool, the learning cost is not low, and AI agent drive is usually not offered.

Choosing by scenario, and price

Choose by scenario first. Simple parts, flanged plates, and brackets, for personal 3D printing: choose cadAI, opening the page, setting the parameters first, building the rough shape, drilling the holes, measuring, previewing, and exporting, with a hand check before export. You want an AI agent to do the work: choose cadAI, with one sentence split into several steps, the parameters stated clearly, and a human preview before delivery. Your parts carry complex curved surfaces, or you need assembly motion simulation or CAM: choose Fusion 360 or Onshape, because the scope of cadAI does not reach there.

Then look at price and total cost of ownership. No price numbers are written in this page: cadAI pricing is to be confirmed, and Fusion 360 and Onshape prices follow the official page. Total cost is explained only as a division, with no numbers written. First, the price of the software itself, read on the price page. Second, the learning cost: full features mean a slow start, while light needs do not require learning the whole set. Third, the computer cost: the category that needs local software installed asks more of the computer, while the web version asks less.

Six steps to decide which one to choose

Work through six steps in order.

  1. List the need first. Write down what the parts are — simple parts or complex curved surfaces — and whether the work needs assemblies, CAM, or vendor certification.
  2. Try cadAI first. Open cad.aiglade.cn, build a flanged plate in six steps: set the parameters first, build the rough shape, drill the holes, measure, preview, and export.
  3. Measure the dimensions. Cover the outline, the hole positions, and the key dimensions, because 3D printing starts with checking whether the dimensions are right.
  4. Export and print. Run a hand check of dimensions and tolerances before export, confirm that everything is right, and only then export and print.
  5. When it is enough, do not change tools. When simple parts are built smoothly, the dimensions measure right, and the print comes out usable, there is no need to change to a heavy tool.
  6. When it is not enough, consider the other side then. When the parts carry complex curved surfaces, or the work needs assemblies or CAM, consider Fusion 360 or Onshape then, and before choosing, look at the official page, reading the price, the features, and the learning cost clearly.

cadAI in numbers

Evidence

cadAI is a browser-based parametric CAD from Aiglade, for mechanical part modeling, hole drilling, measurement, and export, with the same kernel on desktop, in the browser, and over MCP. Its kernel is SolidCraft, an independent community project, not an ArtCraft product line. Its AI assistant takes five intents — S-01 primitives, S-02 holes, S-03 conversion, S-04 measurement, and S-05 preview — and it fits simple mechanical parts, flanged plates, and brackets, plus dimension checks before 3D printing. Complex curved surfaces, assembly motion simulation, and CAM toolpaths are outside its scope, and every export needs a hand check of dimensions and tolerances. Pricing is to be confirmed, and this page writes no version numbers, prices, or scores. An open-source web CAD compares with Fusion 360 or Onshape by division of work: light parametric parts choose an open-source web CAD, while complex curved surfaces, assemblies, and CAM choose Fusion 360 or Onshape.

FAQ

Q: How does an open-source web CAD compare with Fusion 360 or Onshape?

For light parametric parts, an open-source web CAD like cadAI is enough: it opens in the browser, supports parametric modeling, and its MCP interface lets an AI agent drive modeling. For complex surfaces, assemblies, and CAM, Fusion 360 or Onshape fit better. This page compares categories only — no versions, prices, or scores.

Q: Does open source mean worse accuracy?

No. Open source describes where the kernel comes from, not a guarantee of accuracy, and commercial CAD does not guarantee accuracy either. Accuracy rests on three steps: setting the parameters in modeling, measuring the dimensions, and running a hand check of dimensions and tolerances before export. When all three steps are done, the dimensions match.

Q: What should you look at before choosing?

Three things. First, whether the parts are inside the scope of what fits. Second, the price, the features, and the learning cost, read on the official page first. Third, try one part: build a flanged plate in six steps, and when it is enough, do not change tools; when it is not enough, consider the other side then.

Not written / to verify

cadAI · Aiglade · 2026-11-12

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