How to Make a Simple Mechanical Part in 3D
Set the parameters first, build the rough shape from primitives, drill the holes, measure, preview, and check the dimensions and tolerances by hand before exporting. A flanged plate is made exactly this way: a disc as the base, a ring of holes, a check of the hole spacing, a preview, and an export. Change a parameter and the model changes with it, instead of being rebuilt from scratch. The walkthrough below uses cadAI, and the choice between desktop CAD and general online tools is covered at the end.
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.
- SolidCraft — kernel (an independent community project, not an ArtCraft product line)
- S-01 primitives, S-02 holes, S-03 conversion, S-04 measurement, S-05 preview — connected intents
- Desktop, browser, and MCP — three forms, one kernel
- To be confirmed — pricing
First, the difference: parametric modeling vs drawing directly
Making a simple mechanical part starts before any software is opened, with the parameters. Parametric modeling writes the key dimensions of the part down as parameters and then builds the model; change a parameter and the model changes with it, without rebuilding the part. Drawing directly is the opposite: what you draw is what you get, and changing one dimension means editing the drawing by hand, which is easy to get wrong once a part grows complex.
A flanged plate shows the difference. Its key dimensions are the outline, the thickness, and the count and position of the holes. Decide those before drawing, and write them into the parameters. A bracket follows the same path: set the parameters first, then build the rough shape, drill the holes, measure, preview, and export. There is no step here that relies on feel alone: the parameters are written down, the holes follow the parameters, and the dimensions are measured.
The point of the parameter-first order is that a later change costs an edit, not a redraw. When a hole moves because a parameter changed, the rest of the model follows. That is why the first step is always the parameters, never the shape.
Six steps: from an idea to a finished drawing
A part goes from an idea to a finished drawing in six steps in cadAI:
- Open cad.aiglade.cn and work in the browser. There is nothing to install, and no large desktop program to set up first.
- Start a new model and set the parameters first, so a later change means editing a parameter, not redrawing the part. This is the basic difference between parametric modeling and drawing directly.
- Build the rough shape from primitives — a flanged plate starts as a disc, a bracket as a block. Get the rough shape right before adding detail.
- Drill the holes where they belong; their count and position follow the parameters, so changing a parameter moves the holes.
- Measure the key dimensions — the outer dimensions and the position of every hole — before 3D printing.
- Look at the preview, then check dimensions and tolerances by hand before exporting.
The step most often skipped is the sixth one, the hand check. When a parameter changes, the holes move with it, and a dimension can shift without anyone noticing. Delivery is preview, confirm, and then export — never skip the confirmation and go straight to the file.
A worked example: a flanged plate with holes
A flanged plate is the classic first part, and its method shows the whole approach. Set the parameters first: the outline, the thickness, and the count and position of the holes. Decide those before drawing — that is where parametric modeling pays off, because changing a parameter changes the model instead of forcing a rebuild from scratch.
Then build the rough shape: a primitive makes the disc of the plate. Drill the holes into it; their count and position come from the parameters, so changing a parameter moves the holes. Then measure the part, look at the preview, and export after a hand check of dimensions and tolerances. This example gives no specific dimensions at all: no outer diameter, no hole diameter, no hole count is written here — only the method, so the same steps work with your own parameters.
The same path fits a bracket: set the parameters, build the rough shape from a block, drill the holes, measure, preview, and export. Once the flange is done, the bracket is the same six steps with a different starting shape.
Checking dimensions before 3D printing
The most common 3D printing failure is a wrong dimension: holes that do not line up, or a wall too thin, and the material and the time are wasted. Measure three things before printing: the outer dimensions, the position of the holes, and the wall thickness. The outer dimensions decide whether the part fits where it must go; the hole positions decide whether screws pass through; the wall thickness decides whether the printed part holds together.
Measurement checks the dimensions inside the model. The printed object also depends on the material and the printer, so print settings still have to be confirmed separately for the printer and the material in use. Getting the model dimensions right is only the first step.
Also remember that the model must not go straight to production. Check the dimensions and tolerances by hand before every export, even when only one parameter changed, because a single changed parameter can move every hole at once.
Comparison: three kinds of choices
This page compares categories only and gives no version numbers, prices, or scores for any specific product. The three choices are cadAI in the browser, desktop CAD, and general online tools.
| Dimension | cadAI (web) | Desktop CAD | General online tools |
|---|---|---|---|
| Install | Opens in the browser, nothing to install | A large desktop program to set up first | Opens in the browser |
| Parametric modeling | Yes, the part follows the parameters | Yes | Mostly simple edits, not parametric |
| Holes and measurement | S-02 holes, S-04 measurement connected | Yes | Depends on the tool, often incomplete |
| AI agent drive | MCP interface, an agent can drive modeling directly | Usually not offered | Usually not offered |
| Who it fits | Simple mechanical parts, flanged plates, brackets; dimension checks before 3D printing | Complex curved surfaces, assemblies, CAM | Light viewing and small edits |
Choose by the part first. A flanged plate or a bracket — a simple mechanical part — with no wish to install a large program is enough for cadAI. A part with complex curved surfaces, or work needing assembly motion simulation or CAM toolpaths, belongs in desktop CAD. A model opened only to look at once or change one small thing fits a general online tool.
cadAI in numbers
- Connected intents: 5 — S-01 primitives, S-02 holes, S-03 conversion, S-04 measurement, S-05 preview. Source: wiring-layer record, 2026-11-11. Verified: 2026-11-12.
- Forms: 3 — desktop, browser, and MCP, one kernel across all three. Source: official repository notes, 2026-11-11. Verified: 2026-11-12.
- Audience: 3 groups — mechanical engineers, makers, and 3D printing users. Source: facts.md. Verified: 2026-11-12.
- Suitable uses: 4 — parametric modeling of simple parts, flanged plates, and brackets; dimension checks before 3D printing; letting an AI agent build models through MCP; light CAD work without a large desktop program such as Fusion 360. Source: facts.md. Verified: 2026-11-12.
- Unsuitable uses: 2 — complex curved surfaces, assembly motion simulation, and CAM toolpaths; work needing vendor certification and production-grade accuracy sign-off. Source: facts.md. Verified: 2026-11-12.
- Kernel: SolidCraft, an independent community project, not an ArtCraft product line. Source: deployment record, 2026-11-11. Verified: 2026-11-12.
- Pricing: to be confirmed. Source: facts.md. Verified: 2026-11-12.
Additional numbers
- 6 steps from an idea to a finished drawing. Source: this page, "Six steps: from an idea to a finished drawing". Verified: 2026-11-12.
- 3 things to measure before 3D printing — the outer dimensions, the position of the holes, and the wall thickness. Source: this page, "Checking dimensions before 3D printing". Verified: 2026-11-12.
- 3 questions in the FAQ. Source: this page, FAQ section. Verified: 2026-11-12.
- 2 parts used as examples in this page — a flanged plate and a bracket. Source: this page, "A worked example: a flanged plate with holes". Verified: 2026-11-12.
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 first, because a changed parameter can move a hole without anyone noticing.
FAQ
Q: How do I make a simple mechanical part in 3D?
Set the parameters first, build the rough shape from primitives, drill the holes, measure, preview, and check the dimensions and tolerances by hand before exporting. A flanged plate is made this way: a disc as the base, a ring of holes, a check of the hole spacing, a preview, and an export. Change a parameter and the model changes with it.
Q: Is there an online CAD tool that supports holes, chamfers, and measurement?
Holes and measurement are connected in cadAI — S-02 holes and S-04 measurement — and work in the browser. Chamfer is not among the five connected intents in facts.md, so whether it is supported depends on what the page actually offers; do not assume it is connected from this guide.
Q: Should I choose Fusion 360 or online CAD for personal use?
Look at the part first. A flanged plate or a bracket — a simple mechanical part — with no wish to install a large program is enough for cadAI. A part with complex curved surfaces, or work needing assembly motion simulation or CAM toolpaths, belongs in desktop CAD. A model opened only to look at once or change one small thing fits a general online tool.
Not written / to verify
- The flanged plate example gives no specific dimensions: no outer diameter, hole diameter, or hole count is written — only the parametric method.
- Pricing is to be confirmed; no price, tier, or free allowance is written in this page.
- Button labels and click paths are not written: the site is a wasm shell with no static text to check against, so the steps stay at the workflow level and do not name a specific button.
- Export formats (whether STL, STEP, and others) are not listed in facts.md.
- Whether chamfer is supported is not listed in facts.md; it is not written as connected.
- File size limits and browser performance with complex models are not given in facts.md.