
## Using the Solid Particle System to Copy Meshes
There is more to the Solid Particle System (SPS) than just producing multiple copies of a mesh and these are considered in full in the Particles section. The SPS places multiple copies of a mesh all together into just one mesh. This means that instead of multiple draw calls there is just one draw call for the single mesh.

The SPS is a single updatable mesh with the same properties as any other Babylon.js  mesh.

In order to produce multiple copies of a mesh you follow this script

Example :
```javascript
SPS = new BABYLON.SolidParticleSystem("SPS", scene);  //create the SPS
const tetra = BABYLON.MeshBuilder.CreatePolyhedron("tetra", {}); //create the mesh
SPS.addShape(tetra, 1500);      // add as many copies as you want to the SPS
tetra.dispose(); //ddispose of the original mesh
const spsMesh = SPS.buildMesh();  //builds the SPS mesh

//Set the function to intialise the particle properties
SPS.initParticles = () => {
    for (let p = 0; p < SPS.nbParticles; p++) {
        const particle = SPS.particles[p]  
        particle.position.x = BABYLON.Scalar.RandomRange(-50, 50);
        particle.position.y = BABYLON.Scalar.RandomRange(-50, 50);
        particle.position.z = BABYLON.Scalar.RandomRange(-50, 50);
    
        const scale = BABYLON.Scalar.RandomRange(0.5, 1.5);;
        particle.scale.x = scale;
        particle.scale.y = scale;
        particle.scale.z = scale;

	        particle.rotation.x = BABYLON.Scalar.RandomRange(0, Math.PI);
	        particle.rotation.y = BABYLON.Scalar.RandomRange(0, Math.PI);
	        particle.rotation.z = BABYLON.Scalar.RandomRange(0, Math.PI);
    }
} ;


SPS.initParticles(); //call the initialising function
SPS.setParticles(); //apply the properties and display the mesh
```

## Example
Copying a tetrahedron: <Playground id="#GKUCQP" title="Copying a Tetrahedron" description="Simple example of copying a tetrahdedron." image="/img/playgroundsAndNMEs/PGNMEProceduralTexture.jpg"/>


## How to use Instances
Instances are an excellent way to use hardware accelerated rendering to draw a huge number of identical meshes (let's imagine a forest or an army).

Instances are built from a mesh with the following code:

```javascript
// In this case we're loading our mesh from an external source.
BABYLON.SceneLoader.ImportMesh("", "//www.babylonjs.com/assets/Tree/", "tree.babylon", scene, function (newMeshes) {
    var mesh = newMeshes[0];
    // Make the "root" mesh not visible. The instanced versions of it that we
    // create below will be visible.
    mesh.isVisible = false;
    for (var index = 0; index < 100; index++) {
        var newInstance = mesh.createInstance("i" + index);
        // Here you could change the properties of your individual instance,
        // for example to form a diagonal line of instances:
        //  newInstance.position.x = index;
        //  newInstance.position.z = index;
        // See below for more details on what can be changed.
    }
});
```
A mesh can have as many instances as you want.

Each instance has the same material as the root mesh. They can vary on the following properties:
* ```position```
* ```rotation```
* ```rotationQuaternion```
* ```setPivotMatrix```
* ```scaling```

Note: related are **thin instances**, if you want yet more performances but with less control on each instance. See the [dedicated page](/features/divingDeeper/mesh/copies/thinInstances) for further information.

## Instancing a glTF object

When you instanciate a glTF object, you need to make sure that the new instance will be under the same parent or you need to remove the parent from the source object.

This is because every gltf file comes from a right handed world. To get it into Babylon.js left handed world, we are adding an arbitrary parent that is adding a negative scale on z.

So when instancing a glTF object you have to (either):
- Call `source.setParent(null)`
- Or call `newInstance.setParent(source.parent)`

## Custom buffers

You also have the opportunity to specify per instance values for any attribute. For instance (no pun intended), if you want to have a specific color per instance, you only need to provide a vertex buffer flagged as "instanceable" and fill it with a color per instance:

```javascript
let instanceCount = 1000;
let colorData = new Float32Array(4 * instanceCount);

for (var index = 0; index < instanceCount; index++) {
    colorData[index * 4] = Math.random();
    colorData[index * 4 + 1] = Math.random();
    colorData[index * 4 + 2] = Math.random();
    colorData[index * 4 + 3] = 1.0;
}

var buffer = new BABYLON.VertexBuffer(engine, colorData, BABYLON.VertexBuffer.ColorKind, false, false, 4, true);
box.setVerticesBuffer(buffer);
```

The last parameter of the VertexBuffer constructor is the one to set to true to flag it as instanceable.

Example: <Playground id="#8L50Q3#1" title="Custom Buffers Example 1" description="Simple example of custom buffers."/>

The other way is to register a custom buffer with `registerInstancedBuffer`:
```javascript
mesh.registerInstancedBuffer("color", 4); // 4 is the stride size eg. 4 floats here
```

Using this API, you can specify a new buffer that will be instancied. This means that each instance will have its own value. You can specify this value on the root mesh and on every single instance:

```javascript
box.instancedBuffers.color = new BABYLON.Color4(Math.random(), Math.random(), Math.random(), 1);
let instance = box.createInstance("box1");
instance.instancedBuffers.color = new BABYLON.Color4(Math.random(), Math.random(), Math.random(), 1);
```

The system will take care of updating the internal vertex buffer.

Example: <Playground id="#YPABS1" title="Custom Buffers Example 2" description="Simple example of custom buffers."/>

## Advanced control

You can decide to control the world matrix instanced buffer the same way you control the custom buffers.

To do so, just run the following code:
```javascript
mesh.manualUpdateOfWorldMatrixInstancedBuffer = true;
```

When this mode is activated, you can update the world matrix instanced buffer with this code:
```javascript
mesh.worldMatrixInstancedBuffer.set(mat, offset); // mat is the matrix you want to store at the given offset
offset += 16; (a matrix is composed of 16 floats
```

It is recommended to freeze the active meshes when controling the world matrix instanced buffer to avoid having a discrepancy between the values you store and the number of active instances:
```javascript
scene.freezeActiveMeshes(true);
```

You can find a complete example here: <Playground id="#HJGC2G" title="Instancing Advanced Control" description="Simple example of instancing advanced controls."/>

## Support

Instances are supported for collisions, picking, rendering and shadows. Even if the current hardware does not support hardware accelerated instances, babylon.js will be able to optimize rendering to take instances into account.

Starting from 5.0, instances that have a transparent material applied can be sorted from back to front to remove/limit rendering artifacts. This mode is enabled by setting `BABYLON.Mesh.INSTANCEDMESH_SORT_TRANSPARENT = true`.

Note that for performance sake the master mesh (the mesh from which instances are created by calling `masterMesh.createInstance`) is not taken into account in the sorting process. So, to avoid rendering artifacts between this mesh and its instances, this mesh should be disabled (`masterMesh.setEnabled(false)`).

## Using 3D modeler to create instances

## Blender

Using Blender, you can create instances of a mesh by just creating a linked object:

![](/img/how_to/use-instance/blender-linked-object.jpg)

## 3DS Max

Using 3DS Max, you can create instances of a mesh by just creating a clone instance object with clic right on the object:

![](/img/how_to/use-instance/3ds-linked-object.jpg)

## Limitations

* You can use instances with LOD but one limitation will apply in this case: You will have to hide the root objects.
Here is an example where LODs reuse instances:
<Playground id="#0720FC#10" title="Instances and LODs" description="Simple example of instancing and LODs."/>

* Instances with a world matrix where determinant is different than root mesh world matrix will be rendered separately (like a regular mesh). This mostly happens when the sign of the scaling vector is different between an instance and the root mesh.

* When using motion blur, the engine needs to store world matrices of the previous frame to compute velocity. Usually, this part is taken care of internally, but in certain cases you may have to specify these matrices manually. You may in fact see weird blurring artifacts if you update your world matrix buffer manually (using `mesh.manualUpdateOfWorldMatrixInstancedBuffer = true;`). In that case, to also update previous world matrices, you must enable the corresponding flag : 
```javascript
mesh.manualUpdateOfPreviousWorldMatrixInstancedBuffer = true;
```

And similarly to world matrices, update the previous world matrices :
```javascript
mesh.previousWorldMatrixInstancedBuffer.set(previousMat, offset);
```
Here is an example of manual update of world matrices along with previous world matrices, to use motion blur correctly with instances :
<Playground id="#HJGC2G#58" title="Instances previous matrices motion blur" description="Updating manually previous world matrices for instances to work with motion blur"/>

## Demos
- Trees: <Playground id="#YB006J#75" title="Instancing Trees Example" description="Simple example of instancing with trees."/>
- 10,000 Icospheres: <Playground id="#c2ynt9#12" title="10,000 Icospheres" description="Simple example of instancing with 10,000 icospheres."/>



## Clone
This simply creates a deep copy of the original mesh and saves memory by sharing the geometry. Each clone can have its own material and transformation.


Note that as of v5.0, cloning a mesh with skeleton will assign said skeleton to the clone, ie, the skeleton is shared. If your clone does not need a skeleton, simply set it to null.
```javascript
clone.skeleton = null;
```
Alternatively, if your clone needs a skeleton, simply clone's the source mesh's skeleton.
```javascript
clone.skeleton = mesh.skeleton.clone();
```

## Examples
<Playground id="#QMFPPE" title="Cloning Example 1" description="Simple example showing shared geometry by scaling one geometry by 2." isMain={true} category="Mesh"/> Shows shared geometry by scaling one geometry by 2.  

``` ```
<Playground id="#QMFPPE#1" title="Cloning Example 2" description="Simple example showing transformation by scaling of 2 only changes one mesh."/> Shows transformation by scaling of 2 only changes one mesh.  

``` ```
<Playground id="#QMFPPE#2" title="Cloning Example 3" description="Simple example of clones with different materials."/> Different materials.  


Cloning With the Solid Particle System

Using the Solid Particle System to Copy Meshes

Example