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Parts

When you build models with multiple components, auto-fusion can work against you — you don't want a bolt to merge into a bracket. part() creates isolation boundaries so components stay separate.

Defining a part​

Wrap modeling operations in a part() call:

import { part, sketch, extrude } from 'fluidcad/core';
import { rect, circle } from 'fluidcad/core';

part("base", () => {
    sketch("xy", () => {
        rect(120, 80).center()
    })
    extrude(10)
})

part("pillar", () => {
    sketch("xy", () => {
        circle(30)
    })
    extrude(60)
})

Shapes inside "base" fuse with each other, and shapes inside "pillar" fuse with each other, but the two parts stay separate — even though the pillar sits on top of the base.

Passing options​

The part() callback receives an options object. You pass options when you instantiate the part with use():

import { part, use, cylinder, select, color } from 'fluidcad/core';
import { face } from 'fluidcad/filters';

const peg = part("peg", (options) => {
    cylinder(options?.radius || 10, options?.height || 40)
    select(face())
    color("orange")
})

use(peg, { radius: 15, height: 60 })    // custom size
use(peg)                                  // default size

Use options?.property || defaultValue to provide defaults when an option isn't passed.

Importing parts from other files​

Parts are regular ES module exports. Define a part in one file and import it in another:

// peg.fluid.js
import { part, cylinder, select, color } from 'fluidcad/core';
import { face } from 'fluidcad/filters';

export const peg = part("peg", (options) => {
    cylinder(options?.radius || 10, options?.height || 40)
    select(face())
    color("orange")
})
// assembly.fluid.js
import { peg } from './peg.fluid.js';
import { use, sketch, extrude, translate } from 'fluidcad/core';
import { rect } from 'fluidcad/core';

// Base plate
sketch("xy", () => {
    rect(100, 60).center()
})
extrude(5)

// Place pegs with different sizes
const p1 = use(peg, { radius: 8, height: 30 })
translate(30, 15, 5)

const p2 = use(peg, { radius: 12, height: 50 })
translate(-30, -15, 5)

This pattern lets you build libraries of reusable parametric components.