Tutorials

The Getting Started guide is a reference — one section per panel. These pages are the other half: each one builds a single real part from start to finish, so you can follow along rather than look things up.

Every tutorial is self-contained and takes 10–20 minutes. They share one convention (below), so doing them in order costs less than dipping in, but any of them works on its own.

Tutorial	What you build	Covers
Your first bracket	An L-bracket with a filleted corner and two counterbored bolt holes	Primitives, booleans, fillets, hole ops, the Edits history
A parametric bolt-circle flange	A round flange whose bolt count and circle radius are driven by variables	Variables, expressions, circular patterns, pattern-then-subtract
A shelled enclosure	An open-topped box built from a 2D sketch	Profile sketches, extrude, shell, build-time face roles
Prepare a part for FEA	The bracket, meshed and exported for Kratos	Parts, per-part mesh sizing, FE meshing, Kratos MDPA export
Model with an AI agent	The same bracket, built by an agent over MCP	The MCP server, apply_edit_ops, inspect, agent verification

The starting point, and why it looks odd

Every tutorial starts by opening examples/STP/block.stp from this repository — a plain 3 × 4 × 5 mm box centred on the origin.

That is not the part you are building. CAD Preview is a read-only previewer: it opens an existing CAD file and records your work in JSON sidecars beside it, never writing the source. So there is no "new empty document" to start from, and every creation op appends a new body rather than replacing what is there.

The convention these tutorials use is to make the first thing you add fully enclose the seed block. Two separate solids in the same model still occlude each other normally, so the seed disappears inside your part and stays out of the way. It remains in the model as solid-0 — you will see it in the Components tree, and it shifts the ids of everything you add afterwards, which is worth knowing before it surprises you.

If you would rather absorb it than hide it, a boolean union between the seed and your first body works too. The trade-off is that a union renumbers the solids, so every id in the tutorial afterwards moves by one.

Reading the operation lists

Each tutorial ends with a Full operation list — the complete op sequence as JSON. It is not a transcript; it is a payload you can use directly:

• Hand it to the MCP server's apply_edit_ops (as the ops array) or run_parametric_script.
• Or paste it into the model's <model>.edits.json sidecar under "ops".

Those blocks are executed by this repository's own test suite on every commit, so an op kind or field that gets renamed breaks the build instead of quietly rotting on this page.

Entity ids (solid-1, face-6, edge-13) are positional — they are indices into the model as it stands at that point in the sequence, and every id in these tutorials was read back from the real kernel rather than guessed. Change an earlier step and the later ids move. The Getting Started guide explains how CAD Preview repairs part assignments when that happens.