> For the complete documentation index, see [llms.txt](https://docs.overthereality.ai/over-sdk-manual/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.overthereality.ai/over-sdk-manual/ovr-component-system-ancient-legacy/essentials.md).

# Essentials

### OVER SDK

The OVER SDK allows you to publish content using all the features of Unity. It also gives you the possibility, through a layer based on a node system, to develop experiences without writing code.

The basic structure is the [OvrNode](/over-sdk-manual/ovr-component-system-ancient-legacy/nodes/ovrnode.md) which has different behaviors according to the functionality it performs.

All [OvrNodes](/over-sdk-manual/ovr-component-system-ancient-legacy/nodes/ovrnode.md) have an editable ID – a list of nodes that are executed before their main function, and a list of nodes that are executed after their main function.\
\
The primary function will be shown in the center of the [OvrNode](/over-sdk-manual/ovr-component-system-ancient-legacy/nodes/ovrnode.md) component.

![](/files/e6bQ8t7kaCRcPCtInyW5)

Thanks to the [OvrVariable](broken://pages/C35D4LQaEdmF6K3tXWCJ) you'll be able to perform calculations, write texts, and control behaviors.

![](/files/J4Hz1qpopoa2k5jy33R7)

Finally, through [Triggers](broken://pages/HiPPC25ar2AfeQi9begN), it is possible to execute multiple [OvrNodes](/over-sdk-manual/ovr-component-system-ancient-legacy/nodes/ovrnode.md) which execute other [OvrNodes](/over-sdk-manual/ovr-component-system-ancient-legacy/nodes/ovrnode.md), according to the **Pre/Post Execution Nodes** assigned. The succession of these executions allows the operation of many dynamics; from the simplest, such as changing the color of a light, to the most complex, such as creating a fully working game.

### DEMO

Inside the OVER SDK you will find a Demo Scene that will help you to understand the use of [OvrNodes](/over-sdk-manual/ovr-component-system-ancient-legacy/nodes/ovrnode.md) to create a mini-game. Moreover, the demo acts as a guide on to how to organize the elements in the scene to keep all the necessary elements ordered for the realization of a project. Specifically, it proposes the creation of a new object for each micro feature created.

![](/files/34tAzWltgyWcZ9O9n72f)