Unreal Engine 5 Tutorial - AI Part 10: Nav Mesh Modifiers

Introduction

In this episode of our AI series, we will explore nav mesh modifiers in Unreal Engine 5. Nav mesh modifiers allow us to change the nav mesh and the costs associated with it, enabling us to create unique and interesting AI behaviors.

Setting Up Nav Mesh Modifiers

The nav mesh is a generated grid that defines the areas in which AI can navigate. By default, each grid space has a cost of 1. Nav mesh modifiers allow us to change this cost to make certain areas more or less appealing for AI to traverse.

To set up a nav mesh modifier, we can use the Nav Modifier Volume, which can be found under the Volumes section in the project settings. By placing this volume in our scene, we can define the areas that will be affected by the nav mesh modifier.

Types of Nav Mesh Modifiers

There are several built-in nav mesh modifiers available in Unreal Engine 5. These include:

Default: This is the default nav area that has no modifications to the cost.
Low Height: This area can be traversed by shorter AI, allowing for different navigation options.
Obstacle: This area increases the cost of traversal, making it less desirable for AI to pass through.
Null: This area cannot be navigated at all by AI.

By selecting the appropriate nav area type and adjusting the cost, we can create dynamic and customizable navigation options for our AI.

Creating Custom Nav Mesh Modifiers

In addition to the built-in nav mesh modifiers, we can also create our own custom modifiers. This can be useful when we want to define specific behaviors for our AI. To create a custom nav mesh modifier, we can create a new blueprint class based on the Nav Area class.

Inside the blueprint, we can adjust the default cost and draw color for the modifier. We can also specify which agents are supported by the modifier.

Dynamic Nav Mesh Modifiers

Nav mesh modifiers can also be set as dynamic. This means that they can change in real-time based on certain conditions. For example, if we want to create a fire obstacle, we can set the nav area modifier on the fire actor to be dynamic. As the fire spreads, the nav mesh cost will increase, making it less appealing for AI to pass through.

FAQ:

What are nav mesh modifiers? Nav mesh modifiers are used to change the nav mesh and the costs associated with certain areas, allowing for customized AI navigation.
How do I set up nav mesh modifiers in Unreal Engine 5? To set up nav mesh modifiers, you can use the Nav Modifier Volume, which can be found in the Volumes section of the project settings. Place the volume in the scene and configure the properties to define the areas affected by the modifier.
Can I create custom nav mesh modifiers? Yes, you can create custom nav mesh modifiers by creating a blueprint class based on the Nav Area class. This allows you to define specific behaviors and costs for AI navigation.
Can nav mesh modifiers be dynamic? Yes, nav mesh modifiers can be set as dynamic. This means that they can change in real-time based on certain conditions. For example, you can create a fire obstacle that spreads and increases the cost of traversal for AI.
How can nav mesh modifiers enhance AI behavior? Nav mesh modifiers can be used to create unique and interesting AI behaviors. By adjusting the costs and properties of certain areas, you can influence how AI navigates and interacts with obstacles in the environment.