# Pattern filling with OpenSCAD

This OpenSCAD module provides the required mechanisms to spray a pattern on a
surface.

## Possible usages

Patterns are widely used in common objects, and so are the possible usages of
this module:
 - [alveolar reinforcement](examples/reinforcement/)
 - moucharabieh
 - decorative patterns
 - surface texturing

## Examples

In the [examples](examples) folder, common examples are provided to illustrate
what can be achieved and how to use this module.

## How to use it

First, you will need to get a copy of this module locally:
```
git clone https://github.com/nmasse-itix/OpenSCAD-Pattern-Filling.git
```

In your OpenSCAD file, include this module:
```
use <OpenSCAD-Pattern-Filling/pattern.scad>
```

Then, build your base shape (in this example, an octogon and a square):
```
module mypattern(r) {
  // The octogon
  rotate([0,0,22.5])
    circle(r=r, center=true, $fn=8);

  // The square
  l = 2 * r * sin(22.5);
  translate([r,r,0])
    rotate([0,0,45])
      square([l,l], center=true);
}
```

Instanciate it once in order to check it matches your expectations:
```
r = 2;
mypattern(r);
```

![our base shape](documentation/images/tutorial_base_shape.png?raw=true)

Then, you need to define two things:
 - a bounding box (the area to spray)
 - the two moves defining how to spray our pattern

```
bounding_box = [
  [0,0],     // Lower left corner
  [20, 20]   // upper right corner
];
moves = [
  [ 2*r, 0], // For the first move, we will translate on x by two times the radius
  [ 0, 2*r], // For the second move, we will translate on y by two times the radius
];
```

Finally, the pattern can be sprayed:
```
spray_pattern(bounding_box, moves)
  mypattern(r);
```

![the sprayed pattern](documentation/images/tutorial_sprayed_pattern.png?raw=true)

If you like clean edges, you can cut the sprayed pattern at bounding box size
by intersecting the pattern with the bounding box:
```
intersection() {
  spray_pattern(bounding_box, moves)
    mypattern(r);
  square(bounding_box[1] - bounding_box[0]);
}
```

![a clean cut of our pattern](documentation/images/tutorial_clean_cut.png?raw=true)

Check [the complete source code](examples/tutorial.scad) for more information.

## Limitations

Currently, the first move needs to be exclusively on the x axis otherwise
the pattern may not be sprayed correctly, leaving blank area.