Navigation Mesh

Warning

Navigation Mesh is currently only available in Isaac Sim with plans release fully in 2023.

Warning

Navigation Mesh is currently in Beta. For more information on pre-release and beta terms, please see the Omniverse License Agreement

Overview

Navigation Mesh, or “Nav Mesh”, is a tool used to generate a polygonal mesh that represents the traversable area of one or more agents. From that mesh, a linear path between two points can be generated.

Setup

Enabling the Extension

Upon enabling the omni.anim.navigation.bundle extension, the Navigation menu will be accessible through Window > Navigation. The omni.anim.navigation.core contains the backend, and the omni.anim.navigation.ui contains the frontend elements.

Creating a Nav Mesh

Nav Mesh is a ground-based system and needs one or more meshes that represent a traversable area to build upon. It can build off of simple geometry or a custom polygon mesh.

Once the meshes are in the scene, generate a Nav Mesh by creating a new volume via Create > Navigation > NavMesh Volume. A new NavMesh volume will be created, and the NavMesh automatically built on the ground.

NavMesh Bake Settings

There are two ways to access the build settings:

• The Window > Navigation > NavMesh menu item

• Select any NavMeshVolume prim in the Stage and and in the Property panel, go to the NavMesh Volume section. Click on the Edit NavMesh Settings button.

Agent Option	Result
Height	The height of the agent size in scene units. The NavMesh will build only in areas where the agent height will fit.
Radius	The radius of the agent size in scene units.The NavMesh will build a buffer area against objects so that the agent cannot get too close to collide through.
Max Slope	The maximum angle in degrees that the NavMesh will build for. If the angle of the base geometry is greater than the slope angle setting, the NavMesh will not build.
Max Climb	The maximum height of objects the agent can step over.

Auto Rebake Option	Result
Auto Rebake	If enabled, upon every stage update the NavMesh will rebuild. WARNING: this can be computationally expensive with large and complex scenes.
Auto Rebake Delay	The time in seconds it takes for the NavMesh to trigger a rebuild after the scene has changed. This is good to use for large and complex scenes.

Cache Option	Result
Enabled	If checked, the system will cache previous results to speed up future bake times.

Bake: Takes the current settings and attempts to create a NavMesh. Cancel All: Cancels the current NavMesh bake.

Baked Mesh Settings

The Baked Mesh panel is used for assigning which objects in the scene will influence NavMesh baking and which ones will not.

Note

By default the NavMesh will exclude rigid Physics bodies. This can be disabled by unchecking Rigid Bodies.

NavMesh Volumes

As many NavMesh Volumes can be added to the Scene as needed by going to Create > Navigation > NavMesh Volume.

NavMesh Volumes can be moved, rotated, and scaled to ensure the right fit. Multiple NavMesh volumes can be be placed near each other to extend new areas of the NavMesh.

NavMesh Obstacles

NavMesh Obstacles can be used to create exclusion zones. Any prim type can have a NavMesh Obstacle attached. To add an Obstacle, right click on a Stage prim and go to Add > Navigation > Add NavMesh Obstacle.

Obstacle shapes can be either boxes or cylinders, and the sizing and offsets can be adjusted.

NavMesh Obstacle Property	Result
Box Size	If the shape is a box, non-uniformly adjust the size of the shape independent of the primary volume
Cylinder Height	If the shape is a cylinder, adjust the height.
Cylinder Radius	If the shape is a cylinder, adjust the radius size.
Offset	Offset the position of the Obstacle volume from the Primary volume
Shape	Choose between Box and Cylinder shapes for the Obstacle volume.

Creating a NavMesh Path

A linear path can be generated between a valid start and end point within the NavMesh. Path Points can be generated in and out of Play mode in Kit.

import omni.anim.navigation.core as nav
import omni.usd
stage = omni.usd.get_context().get_stage()
inav = nav.acquire_interface()

# Set the start and end points. If valid, new path points will be generated along the Nav Mesh.
path = inav.query_navmesh_path((24, 40, 63), (-960, 106, -258))
points = path.get_points()
print(points)