Navigation3D volumetric free-space navigation

Dawn Engine Navigation3D represents flyable 3D free space with a Sparse Voxel Octree (SVO), runs any-angle pathfinding on it, then post-processes paths into followable trajectories for Hover or fixed-wing motion models. It complements surface-based RecastNavigation (navmesh) and also covers climb surfaces plus ground / air / climb hybrid routing.

Maturity: shipped. Provided by the Navigation3D Gem; depends on RecastNavigation and LmbrCentral. After enablement, the system component mounts automatically; you still add volume and agent components on scene entities.

It does not replace Recast ground navigation: ground still uses Detour; Navigation3D owns airspace, climb, and the cross-domain query facade.

What problem it solves

Drones, flying units, cliff climbing, and “walk then fly then land” gameplay need volumetric free-space navigation. A ground navmesh alone cannot express aerial corridors, no-fly zones, or takeoff / landing transfers. Navigation3D provides:

• Runtime voxelization or offline bake of queryable airspace from scene geometry;
• Deterministic single-chunk Lazy Theta* and cross-chunk HPA* pathfinding;
• Runtime cost / no-fly / flight-corridor overlays (no SVO rebuild when they change);
• A unified query facade that routes Ground / Air / Climb / Hybrid / Underwater to the right backend;
• Optional FlightPathFollowComponent desired-velocity output, plus Nav3D.* operators when HtnPlanner is also enabled.

With the Gem disabled, navigation behavior matches a Recast-only project.

How it works

Scene geometry (Recast / PhysX provider)
 │
 ├─ AutoBuild (runtime voxelize) ──► SVO volume (chunks / radius tiers)
 └─ Bake → .svonav → AP → .svonav_baked ──► same (optional streaming pages)
 │
 Query from/to ──► pick tier ──► Lazy Theta* / HPA* ──► geometric path
 │
 Hover / FixedWing post-process
 │
 FlightPath / trajectory
 │
 (optional) FlightPathFollow → desired velocity → game motion

Two rules run through the Gem:

1. A path is not motion: queries return path / trajectory data only; the follow component publishes desired velocity and never writes Transform.
2. Runtime overlay, not rebuild: cost zones, no-fly zones, flight corridors, and domain links are query-time overlays; changing them does not rebuild the SVO.

For large worlds the volume keeps a double-precision m_worldAnchor while the SVO uses volume-local single precision; the unified facade APIs take AZ::Vector3d world coordinates. Open-world projects typically combine this with double-precision rendering and World Streaming.

Quick start (summary)

1. Enable Navigation3D (usually also RecastNavigation).
2. Volume entity: add SVO Navigation Volume plus a same-entity geometry provider (RecastNavigationProviderService); start with Auto build = true.
3. AI entity: add Flight Navigation, then query via FlightNavigationRequestBus or the unified facade.

#include <Navigation3D/FlightNavigationBus.h>

Navigation3D::FlightPath path;
Navigation3D::FlightNavigationRequestBus::EventResult(
 path, agentEntityId,
 &Navigation3D::FlightNavigationRequests::FindFlightPathBetweenPositions,
 fromWorldPos, toWorldPos);

For the full five-step walkthrough, debug draw, and optional following, see Getting started.

Handbook chapters

Glossary

Limits and related capabilities

You can rely on:

• SVO airspace + climb surfaces; AutoBuild / bake / streaming supply modes;
• Deterministic pathfinding and offline–runtime bake parity; runtime cost fields and domain links;
• Unified multi-domain queries; Hover / FixedWing post-process and path-follow helpers;
• Optional HTN operators; nav3d_* diagnostics and volume validation.

Do not assume:

• The follow component writes Transform (you must apply desired velocity);
• AutoBuild still runs when a baked asset is assigned (it is ignored);
• Navigation3D replaces full DetourCrowd ground crowd simulation;
• Meaningful airspace can be voxelized without a geometry provider.

Next steps

• Getting started — shortest path to a working flight query.
• Double-precision rendering / World Streaming — large-world airspace usually pairs with both.
• Flight — feed desired velocity into flight control.
• Water — underwater hybrid routing.
• HTN Planner — drive takeoff / fly / land from a planner.