
## Ground

A ground is a flat horizontal plane parallel to the xz plane which can be subdivided into rectangular regions. The origin of the ground is at the center of the plane. The optional properties for determining the size of the ground are width (x) and height (z) (and yes we all agree that depth would be more descriptive than height!)

## MeshBuilder

Usage :

```javascript
const ground = BABYLON.MeshBuilder.CreateGround("ground", options, scene); //scene is optional and defaults to the current scene
```

| option       | value                                     | default value |
| ------------ | ----------------------------------------- | ------------- |
| width        | _(number)_ size of the width              | 1             |
| height       | _(number)_ size of the height             | 1             |
| updatable    | _(boolean)_ true if the mesh is updatable | false         |
| subdivisions | _(number)_ number of square subdivisions  | 1             |

### Example

Ground: <Playground id="#45R5JK" title="Create a Ground" description="Simple example of creating a ground."/>

## Mesh

Usage

```javascript
const ground = BABYLON.Mesh.CreateGround("ground", width, height, subdivisions, scene);
const ground = BABYLON.Mesh.CreateGround("ground", width, height, subdivisions, scene, updatable); //one optional parameter after scene
```



## Ground From a Height Map

When the ground is created using _groundFromHeightMap_ the surface of the ground can be perturbed by a grayscale image file called a height map. Lighter areas are displayed higher than darker areas. This is a way of creating hills and valleys on your ground.

## MeshBuilder

Usage:

```javascript
const ground = BABYLON.MeshBuilder.CreateGroundFromHeightMap("gdhm", url_to_height_map, options, scene); //scene is optional and defaults to the current scene
```

| option       | value                                                                             | default value          |
| ------------ | --------------------------------------------------------------------------------- | ---------------------- |
| width        | _(number)_ size of the map width                                                  | 10                     |
| height       | _(number)_ size of the map height                                                 | 10                     |
| subdivisions | _(number)_ number of map subdivisions                                             | 1                      |
| minHeight    | _(number)_ minimum altitude                                                       | 0                      |
| maxHeight    | _(number)_ maximum altitude                                                       | 1                      |
| onReady      | _(function)_ a callback js function that is called and passed the just built mesh | (mesh) =\> \{return;\} |
| updatable    | _(boolean)_ true if the mesh is updatable                                         | false                  |

### Examples

The following image is used for the height map in the first examples

![height map](/img/how_to/HeightMap/heightMap.png)  
Low subdivisions: <Playground id="#LQ4LI1" title="Create Ground From A HeightMap - Low Subdivisions" description="Simple example of creating ground from a heightmap with low subdivision."/>
High subdivisions: <Playground id="#LQ4LI1#1" title="Create Ground From A HeightMap - High Subdivisions" description="Simple example of creating ground from a heightmap with high subdivision."/>

Flat world: <Playground id="#LQ4LI1#3" title="Create Ground From A HeightMap" description="Simple example of creating ground from a heightmap."/>

## Mesh

Usage :

```javascript
var ground = BABYLON.Mesh.CreateGroundFromHeightMap("ground", heightMapPath, width, height, subdivisions, minHeight, maxHeight, scene, updatable, onReadyCallback);
```



## Torus Knot
A torus knot is a continuous shape that twists and turns around the surface of a torus. The number of twists and turns are determined by two windings integers p and q. The simplest knotted knot is with 2 and 3 for p and q. The origin of the created torus knot is at the center of the underlying torus.

## MeshBuilder
Example :
```javascript
const torus = BABYLON.MeshBuilder.CreateTorusKnot("torusKnot", options, scene);
```

option|value|default value
--------|-----|-------------
radius|_(number)_ radius of the torus knot|2
tube|_(number)_ thickness of its tube|0.5
radialSegments|_(number)_ number of radial segments|32
tubularSegments|_(number)_ number of tubular segments|32
p|_(number)_ number of windings|2
q|_(number)_ number of windings|3
updatable|_(boolean)_ true if the mesh is updatable|false
sideOrientation|_(number)_ side orientation|DEFAULTSIDE
frontUVs|_(Vector4)_  **ONLY WHEN sideOrientation:BABYLON.Mesh.DOUBLESIDE set** | Vector4(0,0, 1,1) 
backUVs|_(Vector4)_  **ONLY WHEN sideOrientation:BABYLON.Mesh.DOUBLESIDE set** | Vector4(0,0, 1,1) 

### Examples
Simplest: <Playground id="#SVU8U9#1" title="Create a Simple Torus Knot" description="Simple example of creating a simple torus knot."/> 
Low p and q: <Playground id="#SVU8U9#2" title="Create a Torus Knot With Low P And Q" description="Simple example of creating a simple torus knot with low P And Q."/>
High p and q: <Playground id="#SVU8U9#3" title="Create a Torus Knot With High P And Q" description="Simple example of creating a simple torus knot with high P And Q."/>
Breaking the rules - using high non integer P and q: <Playground id="#SVU8U9#4" title="Create a Torus Knot With High non integer P And Q" description="Simple example of creating a simple torus knot with high non integer P And Q."/>

## Mesh
```javascript
const knot = BABYLON.Mesh.CreateTorusKnot("knot", radius, tube, radialSegments, tubularSegments, p, q, scene);
const knot = BABYLON.Mesh.CreateTorusKnot("knot", radius, tube, radialSegments, tubularSegments, p, q, scene, updatable, sideOrientation); //optional parameters after scene
```



option	value	default value
option width	value (number) size of the width	default value 1
option height	value (number) size of the height	default value 1
option updatable	value (boolean) true if the mesh is updatable	default value false
option subdivisions	value (number) number of square subdivisions	default value 1

Creating A Ground

Ground

MeshBuilder

Example

Mesh