Good practices for NavMesh3D generation

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1

Godot Version

4.7.stable

Context

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I’m working on enemy movement/pathfinding. My needs with pathfinding are:

  • Enemies should walk around objects in the scene, like fences, trees and cliffs
  • Enemies should find the ramps that allow them to ascend/descend height-levels in the terrain

I am using a NavigationRegion for this, but I’m getting some complaints from the editor that my geometry is too complex. I’m intending for my terrain to get a bit more complex than this, so I’m a bit worried that I’ll get problems down the line.

  WARNING: modules/navigation_3d/3d/nav_region_builder_3d.cpp:219 - Navigation region synchronization had 4 edge error(s).
  WARNING: More than 2 edges tried to occupy the same map rasterization space.
  WARNING: This causes a logical error in the navigation mesh geometry and is commonly caused by overlap or too densely placed edges.
  WARNING: Consider baking with a higher 'cell_size', greater geometry margin, and less detailed bake objects to cause fewer edges.
  WARNING: Consider lowering the 'navigation/3d/merge_rasterizer_cell_scale' in the project settings.
  WARNING: This warning can be toggled under 'navigation/3d/warnings/navmesh_edge_merge_errors' in the project settings.

I have tried to increase the cell size, but then I get these gaps in the NavMesh.

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It also feels like a lot of the generated mesh is unnecessary; the depression and small hill generate a lot of triangles, despite being fully traversable.

The trees also generate a lot of triangles. I could exchange it so they use avoidance rather than carving the NavMesh, but there’s still a lot of geometry.

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Question

What are the best practices when solving navigation in these types of levels? I have tried to look up guides but nothing quite fits.

Are there approaches that are better than a NavigationRegion in this context?

Can I set up the geometry of the terrain in some way such that the NavMesh becomes cleaner?

Thanks for any pointers and ideas :folded_hands:

2

I don’t know what the best practices are. There’s a lot of settings you can tweak to get different result, but I doubt you will get clean navmesh.

I once get that kind of error, but that happens because of 2 NavigationRegion overlapped with each other which might not be your case.

Other method is to create your own navmesh using blender. It is a lot of work but you will have more control on how the triangle will end up. Then in Godot you turn the mesh into navmesh resource using the mesh option.

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You can also name your mesh in blender with suffix -navmesh so that Godot will automatically import and convert it to a proper node.

This Youtube video might help explaining the workflow for custom NavMesh assuming you are using Blender.