Machine Skill

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name: machine
description: Turn one line ("a turbofan jet engine", "a mechanical watch", "an LVAD heart pump") into a photoreal, physics based, interactive 3D simulation of that machine in a single HTML file, plus a 20 to 30 second film to post it. Real proportions in metres, real materials (PBR metals, paints, polymers, glass), studio lighting with soft shadows, moving parts driven by a small solver that computes real numbers (thrust, torque, rpm, flow, pressure, efficiency), and modes to explode it, cut it open with clean section caps, x-ray it, slow it down, label it and break it. Use this whenever someone asks to build, simulate, visualise, explain or "show how X works" for any machine, engine, mechanism, device, instrument or piece of hardware, wants an interactive 3D model or a cutaway, or wants a video of a machine for a post, even if they never say "simulation" or "three.js".
---

# Machine Skill

You build a machine the way a product studio photographs one and an engineer explains one: the real thing at its real size, in real materials, on a clean studio set, running on real equations. One line in, one HTML file out, and a film in one command.

The output is always:

1. `<name>.html`: a single self contained page (three.js 0.170 from jsDelivr, the kit inlined). It opens from disk, from any static host, or inside an iframe.
2. A film: `node scripts/record.mjs <name>.html out/<name>.mp4 --music freepd:<Category>/<Name>`.

Open `examples/` first. Every example was made from the one line at the top of its page. `examples/turbofan.html` is the reference: read it end to end before you write anything.

## The bar

Before you start, picture the frame a viewer sees after three seconds. It must already look like a studio product photograph of the real machine: correct silhouette and proportions, metal that reads as metal, a soft shadow on a paper floor, nothing floating, nothing clipping, nothing placeholder. Then it moves, and every number on screen is computed.

A result is not done while any of these is true:

- a part a mechanic would expect is missing (no fuel nozzles in a combustor, no escapement in a watch, no valves in an engine)
- something floats, intersects, or has a visible seam or gap at a joint
- a material looks like plastic when it should be metal, or everything is one grey
- a number on screen is typed in rather than computed by the solver
- the cutaway shows hollow shells instead of solid section faces
- the first frame of the film is not beautiful

## Workflow

### 1. Research the real machine (5 minutes, no code)

Write down, in a comment block at the top of the machine script, from what you know (and the web if you have it):

- **The real dimensions** in metres of the 5 to 10 parts that define the silhouette (a turbofan: fan diameter 2.85 m, length 4.9 m, nacelle max diameter 3.44 m).
- **The parts list** in assembly order, each with its material. Aim for 15 to 40 named parts; repeated parts (blades, teeth, bolts, coils) count individually.
- **The physics** that makes it work, as 3 to 6 equations you will actually compute, with real constants and the operating point (a turbofan: Brayton cycle, take-off at N1 100 %, OPR 42, T4 1,750 K, about 330 kN).
- **The one number** a viewer cares about: the hero (thrust, torque, beats per hour, flow, power). It gets a huge serif readout and a thin bar.
- **The input** a viewer wants to drive: one slider (throttle, wind speed, rpm, pump speed, grind size).