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Welcome to the RAIN Wiki

RAIN is an incredible Artificial Intelligence system that helps Unity developers, designers, and artists add intelligent interactive characters to their games. This wiki covers the basics of how to use RAIN with Unity, and explores each RAIN Component in detail.

The wiki is organized into four main sections:

  • Using RAIN
  • AI Characters
  • Environment
  • Customization

For a full screen version of the RAIN Wiki or the RAIN API Document please follow these links:

RAIN Wiki Full Screen

RAIN API Document Full Screen

Using this Wiki

The first section, Using RAIN, includes:

Getting StartedStart here! This is a guide for anyone new to RAIN. It addresses the RAIN workflow in Unity, the User Interface, and How-to guides such as downloading/installing the package and tutorials/projects.

RAIN Elements and Components – a quick reference guide explaining the properties of each RAIN Element and RAIN Component.

The second section, AI Characters, includes:

AI Characters – An overview of the entire AI Rig and how to use it to build an AI Character. This section also includes detailed information for theory and execution for each AI element.

Behavior Trees – An overview of behavior trees, how they are used in RAIN, and where to start with the editor.

The third secion, Environment, includes:

Environment – An overview of the Environment, dealing with the various tasks and tools involved in marking up a scene for use by an AI. You will find detailed information including theory and execution on Navigation, Waypoints and Entities/Aspects.

The fourth section, Customization, includes:

Customizations Overview – Start customizing RAIN and extending the base functionality to meet your specific needs. This section discuss how to create your own implementations of the standard base classes.

About RAIN

RAIN is a free engine and toolset created by Rival Theory for adding artificial intelligence to games and simulations built in Unity. It combines all aspects of developing AI in Games and Interactive media into a seamless design experience. RAIN is the most utilized AI Engine for Unity, with a growing community nearing 100,000 RAIN developers.

The major functionality of RAIN is divided into 3 main parts:

  • RAIN provides tools for building individual Characters, self-directed personalities that produce motion and action based on internal state and reasoning.
  • RAIN also provides tools for altering the Environment (props, scenes, aspects) so that the AI can understand the world in which it exists.
  • In addition, RAIN supports developer extensions for supplementing or overriding built in functionality.

Additional Resources

To find the most up-to-date information about our resources, in addition to this wiki, visit

For the latest version of RAIN download it from Download Rain

start.txt · Last modified: 2014/04/14 22:58 by codersexpo