# I'm a Render Engine developer, how can I support Skatter?

Scattered instances are stored in an hash/array structure which can be read by render engines (or anyone for that matter). This is very similar to parsing the model and reading the transformation of regular Component Instances. \
This allows users to render hundreds of thousands of instances without overloading Sketchup.

The hash is in a shared namespace called **`Common`**, and its name is **`render_instances`**.

It is structured like so:

```
{ 
	Sketchup.active_model.definitions.entityID => { 
		plugin_name => {
			comp_def => [
				{:transformation => trans1, :material => mat1},
				{:transformation => trans2, :material => mat2},
				...
			]
		}
	}
}
```

* ***Sketchup.active\_model.definitions.entityID***  is used to differentiate models on OSX, as we can have multiple models opened in one Sketchup instance
  * ***plugin\_name***  is the plugin's name, in this case "skatter". This level is necessary so we don't overwrite each other's data
  * ***comp\_def***  is the [Sketchup::ComponentDefinition](http://ruby.sketchup.com/Sketchup/ComponentDefinition.html) of the scattered object. Each item of this array is an individual instance generated by Skatter.
    * ***:transformation*** is a [Geom::Transformation](http://ruby.sketchup.com/Geom/Transformation.html) that represents the instance's transform
    * ***:material*** is a [Sketchup::Material](http://ruby.sketchup.com/Sketchup/Material.html) assigned to the instance. If this is not defined or nil, simply consider this instance as having the default material applied to it, just like a regular Component Instance.

Reading this in Ruby is pretty simple:

```
modelID = Sketchup.active_model.definitions.entityID

if defined?(Common.render_instances) && Common.render_instances[modelID]
	for plugin_name, definitions in Common.render_instances[modelID]
		for definition, instances in definitions 
			for instance in instances
				
				transform = instance [:transformation]
				material = instance [:material]
				
				# Then do your stuff using definition, transform and material...
			
			end#for
		end#for
	end#for
end#if
```

Additionally, you can add an observer to the Common module, and Skatter will call it every time it updates. It is useful if you are doing Real Time rendering.

```
class MyObserver
	def on_render_instances_updated(model_id, plugin_name, definition)
	
		puts model_id.to_s + " -> " + plugin_name + " -> " + definition.name
		
		data = Common.render_instances[model_id][plugin_name][definition]
	
	  # Then do your stuff...
	
	end
end

Common.add_observer(MyObserver.new)
```

If you have any question or need a NFR license to test your implementation with Skatter, contact us at  <skatter@lindale.io>.

{% hint style="info" %}
This is an open protocol, so if other plugins use it, you will automatically support them as well.
{% endhint %}


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