Patterns

Patterns create parametric arrays of geometry from a single feature. Instead of manually copying and positioning parts, define the pattern once and let vcad generate all copies.

Linear Pattern

Creates copies of a part along a direction vector with uniform spacing.

.linear_pattern(dx: f64, dy: f64, dz: f64, count: usize) -> Part

The spacing between copies is calculated as distance / (count - 1).

// Create 4 holes spaced 30mm apart along X axis
let hole = centered_cylinder("hole", 3.0, 10.0, 32);
let row = hole.linear_pattern(90.0, 0.0, 0.0, 4);
// Creates holes at X = 0, 30, 60, 90

Diagonal Patterns

Combine direction components for diagonal patterns:

// Pattern at 45 degrees in XY plane
let pin = centered_cylinder("pin", 2.0, 8.0, 24);
let diagonal = pin.linear_pattern(40.0, 40.0, 0.0, 5);

2D Grid Pattern

Chain linear patterns to create grids:

let hole = centered_cylinder("hole", 2.5, 10.0, 32);

// 4 columns x 3 rows grid
let grid = hole
    .linear_pattern(30.0, 0.0, 0.0, 4)   // 4 copies along X
    .linear_pattern(0.0, 20.0, 0.0, 3);  // 3 copies along Y
// Creates 12 holes total

3D Grid Pattern

Add a third linear pattern for volumetric arrays:

let cube = centered_cube("block", 5.0, 5.0, 5.0);

let lattice = cube
    .linear_pattern(10.0, 0.0, 0.0, 4)
    .linear_pattern(0.0, 10.0, 0.0, 4)
    .linear_pattern(0.0, 0.0, 10.0, 4);
// Creates 64 cubes in a 4x4x4 grid

Circular Pattern

Creates copies of a part around the Z axis with uniform angular spacing.

.circular_pattern(radius: f64, count: usize) -> Part

Copies are always distributed evenly across a full 360-degree circle.

// 6 holes around a 30mm radius
let hole = centered_cylinder("hole", 3.0, 10.0, 32)
    .translate(30.0, 0.0, 0.0);  // Position at desired radius
let pattern = hole.circular_pattern(0.0, 6);

Bolt Circle Pattern

For standard bolt patterns, use the bolt_pattern helper:

bolt_pattern(
    count: usize,
    bcd: f64,
    hole_dia: f64,
    depth: f64,
    segments: i32
) -> Part

// 6 holes on a 60mm bolt circle diameter
let holes = bolt_pattern(6, 60.0, 5.5, 10.0, 32);
let flange = centered_cylinder("flange", 45.0, 8.0, 64) - holes;

Offset Start Angle

The first copy is placed at 0 degrees (positive X direction). To offset:

// Start pattern at 30 degrees instead of 0
let slot = centered_cube("slot", 10.0, 2.0, 5.0)
    .translate(25.0, 0.0, 0.0)
    .rotate(0.0, 0.0, 30.0);  // Pre-rotate the original

let pattern = slot.circular_pattern(0.0, 6);

Radial Features

For features that point outward from the center (spokes, slots):

// Radial vent slots
let slot = centered_cube("slot", 15.0, 2.0, 5.0)
    .translate(20.0, 0.0, 0.0);  // Offset from center

let vents = slot.circular_pattern(0.0, 8);

Nested Patterns

Patterns can be nested to create complex arrays:

// Circular pattern of linear patterns
let hole = centered_cylinder("hole", 2.0, 10.0, 32);

// Create a row of 3 holes
let row = hole.linear_pattern(10.0, 0.0, 0.0, 3);

// Position row at radius and repeat around circle
let pattern = row
    .translate(30.0, 0.0, 0.0)
    .circular_pattern(0.0, 6);
// Creates 18 holes total (3 x 6)

Pattern Behavior

Examples

Mounting Plate with Hole Grid

use vcad::{centered_cube, centered_cylinder};

let plate = centered_cube("plate", 100.0, 80.0, 5.0);

let hole = centered_cylinder("hole", 3.0, 10.0, 32)
    .translate(-40.0, -30.0, 0.0);  // Start position

let holes = hole
    .linear_pattern(80.0, 0.0, 0.0, 5)   // 5 holes along X
    .linear_pattern(0.0, 60.0, 0.0, 4);  // 4 rows along Y

let result = plate - holes;

Hub with Lightening Holes

use vcad::{centered_cylinder, bolt_pattern};

// Main hub body
let hub = centered_cylinder("hub", 50.0, 15.0, 64);

// Center bore
let bore = centered_cylinder("bore", 12.0, 20.0, 32);

// Bolt pattern on 70mm BCD
let bolts = bolt_pattern(8, 70.0, 6.5, 20.0, 32);

// Lightening holes between bolt holes
let light_hole = centered_cylinder("light", 8.0, 20.0, 32)
    .translate(25.0, 0.0, 0.0)
    .rotate(0.0, 0.0, 22.5);  // Offset 22.5 degrees from bolts

let lightening = light_hole.circular_pattern(0.0, 8);

let result = hub - bore - bolts - lightening;

Linear Rail Mount

use vcad::{centered_cube, centered_cylinder};

let rail = centered_cube("rail", 200.0, 20.0, 10.0);

// Countersunk mounting holes
let hole = centered_cylinder("hole", 2.5, 15.0, 24)
    .translate(-80.0, 0.0, 0.0);

let holes = hole.linear_pattern(160.0, 0.0, 0.0, 5);

let result = rail - holes;

Method Reference