3d example don't work

it's a good thing the usage actually tells you what to do instead of telling you to use the example

The issue is about a 3D example not working in a Godot boids extension. Look for example files or scenes in the repository, likely in an `examples/` directory. Run the 3D example in Godot to see the error, then check the Rust GDExtension bindings for 3D flocking logic. The fix will involve comparing the working 2D example to the broken 3D one.

Written by the indexing model from the issue text.