
## Extruded Non Regular Polygon
*ExtrudePolygon* adds a *depth* option to *CreatePolygon*. The extrusion is carried out down the vertical y axis from the polygon shape in the horizontal xz plane. Like *CreatePolygon*, it requires an Earcut script. Since it can be concave, it requires a way to fill the polygon with triangles, and an Earcut method is used. Although an Earcut script is pre-loaded in the Playground, you will have to add a reference to such a script in your own projects. One is available from the [CDN](https://unpkg.com/earcut@2.1.1/dist/earcut.min.js) or via a [npm package](https://github.com/mapbox/earcut#install).

On creation the local origin of the extruded polygon is coincident with the world origin. It is not possible to give a position relative to the extruded polygon as this depends on the data sets used.

*ExtrudePolygon* calls [PolygonMeshBuilder](/features/featuresDeepDive/mesh/creation/param/polyMeshBuilder). There is no *instance* option. You must set at least the _shape_ and _depth_ options.

## MeshBuilder
Usage :
```javascript
const extrudedPolygon = BABYLON.MeshBuilder.ExtrudePolygon("polygon", options, scene); //scene is optional and defaults to the current scene
```

option|value|default value
--------|-----|-------------
shape|_(Vector3[])_  array of Vector3, the shape you want to turn **REQUIRED** |
depth|_(number)_  the depth of the extrusion **REQUIRED** |
faceColors|_(Color4[])_ array of 3 _Color4_, one per box face|Color4(1, 1, 1, 1) for each side
faceUV|_(Vector4[])_ array of 3 _Vector4_, one per box face| UVs(0, 0, 1, 1) for each side
wrap|_(boolean)_ maps texture to sides with faceUV[1] when false texture mapped to each individual side, when true wrapped over all sides |false
holes|_(Vector3[][])_  array of holes, each hole being an array of successive Vector3 | [] 
updatable|_(boolean)_ true if the mesh is updatable|false
sideOrientation|_(number)_ side orientation|DEFAULTSIDE

All vectors for shape and holes are Vector3 and should be in the xz plane, i.e. of the form BABYLON.Vector3(x, 0, z), and in **counter-clockwise** order.

## Examples
Extruded Polygon: <Playground id="#KIEYA6" title="Extruding Irregular Polygons" description="Simple example of extruding irregular polygons."/>
Extruded Polygons using faceUV, one with wrap, one without: <Playground id="#KIEYA6#1" title="Extruding Irregular Polygons Advanced" description="Simple example of extruding irregular polygons."/>


## Mesh
```javascript
let polygon = BABYLON.Mesh.CreatePolygon("polygon", shape, depth, scene);
let polygon = BABYLON.Mesh.CreatePolygon("polygon", shape, depth, scene, holes, updatable, sideOrientation); //optional parameters after scene
```



## Polygon Mesh Builder
*CreatePolygon* and *ExtrudePolygon*, which follow the same form as other mesh creation methods, call *PolygonMeshBuilder*, which can also be used directly. It has some advantages but cannot be used with *faceUVs*. The data used to describe the polygon is given as 2D vectors, (x, y), rather than (x 0, z). In addition to polygon data as an array of vector2s, you can pass a Path2 object. The advantage of using Path2 is that curves can be described using simple methods rather than your own functions. The data used to describe the polygon shape must be in counterclockwise order.

*PolygonMeshBuilder* works by constructing and returning the triangulation of the polygon, then creating the mesh from this triangulation using its *build* method. The triangulation requires an Earcut script. While an Earcut script is pre-loaded in the Playground, you will have to add a reference to such a script in your own projects. One is available at [CDN](https://unpkg.com/earcut@2.1.1/dist/earcut.min.js) or via a [npm package](https://github.com/mapbox/earcut#install).

The build function takes two optional parameters: the first is a Boolean and is true if the mesh is to be updatable, and the second is the depth of the extrusion when required.


## Constraints
The polygon and any holes inside it must be [simple](https://en.wikipedia.org/wiki/Simple_polygon), that is, they must have no overlapping sides. Holes should be wholly inside the polygon and should not be too close to the sides of the polygon or to each other, otherwise the mesh will be malformed. This [algorithm](http://geomalgorithms.com/a09-_intersect-3.html#Simple-Polygons) is one you can use to check whether a polygon is simple.

![Safe Construction](/img/how_to/PolyMeshBuild/pmberr1.webp)

![Unsafe Construction](/img/how_to/PolyMeshBuild/pmberr2.webp)

![Unsafe Construction](/img/how_to/PolyMeshBuild/pmberr3.webp)

## Usage
```javascript
const polygon_triangulation = new BABYLON.PolygonMeshBuilder("name", vector2 array, scene);
const polygon = polygon_triangulation.build();
```


```javascript
var polygon_triangulation = new BABYLON.PolygonMeshBuilder("name", Path2, scene);
var polygon = polygon_triangulation.build(false, 3);
```

### Holes
A hole can only be given as an array of vector2s, representing the corners of the hole in consecutive counterclockwise order around the hole.

Holes are added to the polygon triangulation using the addHole function.

```javascript
polygon_triangulation.addHole(hole1);
polygon_triangulation.addHole(hole2);
polygon_triangulation.addHole(hole3);
var polygon = polygon_triangulation.build(true, 1.4);
```
## Examples
Each example contains polygons described with vector2s and with Path2.
Simple Polygons: <Playground id="#2NJYI5" title="Simple Polygons" description="Example of creating simple polygons with Mesh Builder."/> 
Simple Extruded Polygons: <Playground id="#2NJYI5#1" title="Simple Extruded Polygons" description="Example of simple extruded polygons with Mesh Builder."/>
Polygons with holes: <Playground id="#2NJYI5#2" title="Polygons With Holes" description="Example of creating polygons with holes."/>
Extruded Polygons with holes: <Playground id="#2NJYI5#3" title="Extruded Polygons With Holes" description="Example of extruding polygons with holes."/>



## Non Regular Polygon
A polygon of any type, regular or irregular, convex or concave, is created in the horizontal xz plane. Since it can be concave, it requires a procedure to fill the polygon with triangles, and an Earcut method is needed. While an Earcut script is pre-loaded in the Playground, you will have to add a reference to such a script in your own projects. One is available at [cdn](https://unpkg.com/earcut@2.1.1/dist/earcut.min.js) or via a [npm package](https://github.com/mapbox/earcut#install).

On creation, the local origin of the polygon is coincident with the world origin. It is not possible to give a position relative to the polygon, as this depends on the data sets used.

*CreatePolygon* calls [PolygonMeshBuilder](/features/featuresDeepDive/mesh/creation/param/polyMeshBuilder). There is no *instance* option. You must set at least the _shape_ option. 

## MeshBuilder
Usage :
```javascript
const polygon = BABYLON.MeshBuilder.CreatePolygon("polygon", options, scene); //scene is optional and defaults to the current scene
```

option|value|default value
--------|-----|-------------
shape|_(Vector3[])_  array of Vector3, the shape you want to build **REQUIRED** |
holes|_(Vector3[][])_  array of holes, each hole being an array of successive Vector3 | []
updatable|_(boolean)_ true if the mesh is updatable|false
sideOrientation|_(number)_ side orientation|DEFAULTSIDE
frontUVs|_(Vector4)_  **ONLY WHEN sideOrientation:BABYLON.Mesh.DOUBLESIDE is an option** | Vector4(0,0, 1,1) 
backUVs|_(Vector4)_  **ONLY WHEN sideOrientation:BABYLON.Mesh.DOUBLESIDE is an option** | Vector4(0,0, 1,1) 

All vectors for the shape and holes are Vector3s and should be in the xz plane, i.e. of the form BABYLON.Vector3(x, 0, z), and in **counter clockwise** order. You just list all the vertices of the polygon, and *CreatePolygon* closes the shape.

### Example
polygon with holes: <Playground id="#ZD60FU" title="Create a Polygon With Holes" description="Simple example of creating a polygon with holes."/>


## Mesh
```javascript
let polygon = BABYLON.Mesh.CreatePolygon("polygon", shape, scene);
let polygon = BABYLON.Mesh.CreatePolygon("polygon", shape, scene, holes, updatable, sideOrientation); //optional parameters after scene
```

option	value	default value
shape	(Vector3[]) array of Vector3, the shape you want to turn REQUIRED
depth	(number) the depth of the extrusion REQUIRED
faceColors	(Color4[]) array of 3 Color4, one per box face	Color4(1, 1, 1, 1) for each side
faceUV	(Vector4[]) array of 3 Vector4, one per box face	UVs(0, 0, 1, 1) for each side
wrap	(boolean) maps texture to sides with faceUV[1] when false texture mapped to each individual side, when true wrapped over all sides	false
holes	(Vector3[][]) array of holes, each hole being an array of successive Vector3	[]
updatable	(boolean) true if the mesh is updatable	false
sideOrientation	(number) side orientation	DEFAULTSIDE

Irregular Polygon Extrusion

Extruded Non Regular Polygon

MeshBuilder

Examples

Mesh