Real Time Navigation (3D)

Introduction

Pathfinding in a 3D environment is crucial for many games, it's commonly how non directly controlled characters or entities find their way around an environment. Godot provides several nodes for this purpose:

The map and navigation regions

The "map" is the entire world for navigation, it's similar to "space" for the physics engine. It's comprised of navigation regions, these regions define what parts of the world that can be navigated around by navigation agents.

To create a navigation region add the NavigationRegion3D<class_NavigationRegion3D> node to a 3D scene. Next in the inspector for that region create or add a NavigationMesh. The navmesh contains options for how it will be generated when it's baked. The geometry options control which nodes, and types of nodes, are used to bake the mesh. A full description of each setting and how it works can be found in the NavigationMesh class reference.

Once the settings have been properly configured press the "Bake NavMesh" button at the top of the inspector to generate it.

../../_images/bake_navmesh.png

Note

It can also be generated at runtime using the bake_navigation_region() method of the navigation region node.

Once the mesh has finished generating you should see the transparent navigation mesh above the areas in the scene that can be navigated to.

../../_images/baked_navmesh.png

Keep in mind that the navmesh shows where the center of an entity can go. For example, if you set the agent radius to 0.5 then the navigation mesh will have a distance of 0.5 from any ledges or walls to prevent clipping into the wall or hanging off of the edge.

Navigation agents can moved from one region to another if they are next to each other. Additionally A baked navmesh can be moved at runtime and agents will still be able to navigate onto it from another region. For example, navigating onto a moving platform that has stopped will work.

RVO processing

RVO stands for reciprocal velocity obstacle. RVO processing is a way to pathfind while taking into account other agents and physics bodies that are also moving.

To use it set a target like normal. Then an agent needs to fetch its next nav path location, and compute its velocity to that location. Instead of using that value to move use it to set the velocity on the agent with set_velocity. Then a new velocity that takes into account other agents and obstacles is generated and emitted with the signal velocity_computed.

However agents can only take into account a set number of other nearby agents, this is the max neighbors property of an agent and can be adjusted. This is not a limit for how many agents can use a navigation region at the same time.