Why is the NavMesh blue preview not showing in Scene view?

The Navigation window must be open (Window > AI > Navigation) to trigger the preview, and you must be on the Bake tab. Closing the window hides the gizmo. Alternatively enable Show NavMesh under the Scene view Gizmos dropdown.

Does the NavMesh preview show per-agent type?

Yes. The Navigation window has an Agent Type selector. Only the selected agent's bake is visible. Switch agent types to inspect each one. If you have multiple agent types, each has its own bake data.

What if the NavMesh preview shows but is nearly invisible?

The NavMesh color is set via Preferences > Colors > Navmesh. If it was changed to match the background, or alpha is low, the mesh is technically visible but imperceptible. Reset to default (bright cyan) for clear visualization.

Fix: Unity NavMesh Preview Not Visible in Scene View

Quick answer: Open Window > AI > Navigation (opens the Bake panel) — this triggers the Scene view overlay. Also enable “Show NavMesh” in the Scene view Gizmos dropdown. Switch Agent Type in the Navigation window to inspect different bakes.

Here is how to fix Unity NavMesh preview not visible in Scene view. You baked a NavMesh. Click Bake. Button says “baked successfully.” Scene view shows no blue overlay. You know the bake exists because your agents navigate. But you cannot visually confirm mesh coverage, which makes it impossible to debug narrow corridors or dropped sections.

The Symptom

Scene view does not show the blue NavMesh overlay. Agents at runtime pathfind correctly, confirming bake exists. NavMeshAgent SamplePosition returns valid hits. But visual confirmation is missing.

What Causes This

Navigation window closed. The NavMesh overlay only draws while the Navigation window is open (or while a NavMeshSurface is selected in newer AI Navigation package). Closing the window hides the preview.

Show NavMesh gizmo disabled. Scene view > Gizmos dropdown. Look for “NavMesh” or “AI” category. Checkbox must be on. Even with the Navigation window open, the gizmo toggle overrides.

Wrong Agent Type selected. If you baked for “Humanoid” but the Agent Type dropdown in Navigation window shows “Large Enemy,” you see the Large Enemy’s bake (possibly empty), not Humanoid.

Alpha set too low in Preferences. The NavMesh color has an alpha channel. If low, the overlay is effectively invisible on busy scenes. Reset to defaults.

Bake data missing. If you never actually baked, agents may pathfind on some leftover bake from a previous scene. Or the bake data is in the scene but corrupted. Re-bake to ensure.

The Fix

Step 1: Open the Navigation window. Window > AI > Navigation. Switch to the Object or Bake tab. The blue overlay should appear in Scene view on walkable geometry. If not, proceed to the next step.

For Unity 2022.2+ with AI Navigation package, select a NavMeshSurface component; the bake preview appears when the component is selected.

Step 2: Enable NavMesh gizmo. Scene view > Gizmos dropdown (top-right). Scroll to find NavMesh or Navigation. Check all related categories.

Many projects have custom Scene view filters that hide navigation gizmos. If the checkbox was disabled in a previous session, it stays disabled.

Step 3: Pick the correct Agent Type. In Navigation window > Bake tab, check Agent Type dropdown. Cycle through each to see their bakes. If only one exists, it should always be selected.

If your project has multiple agent types (for different sized units), each has its own bake. Inspect each to verify.

Step 4: Reset NavMesh color. Preferences (Edit > Preferences) > Colors > Navmesh. Reset to default (bright cyan). Check alpha is high. If the mesh was hidden via color tweaks, this fixes it.

Force Rebake

If nothing else works, force a fresh bake:

Navigation window > Bake tab
Clear (removes all bake data)
Bake

The Clear button removes the current NavMesh asset. Bake re-runs from scratch. After baking, the overlay should definitely appear.

AI Navigation Package Version

Unity’s legacy NavMesh system (built-in) and the AI Navigation package (com.unity.ai.navigation) differ. The legacy system uses the Navigation window; the package uses NavMeshSurface components. Which one you use affects where to look for the preview.

For the package: select the NavMeshSurface GameObject. In the Inspector, the surface shows a preview of its bake, including agent radius. The Scene view also shows the mesh when this component is selected.

“The NavMesh is there even if you cannot see it. The preview is a tool; the mesh works regardless. But verify visually when things go wrong.”

Related Issues

For agent stuck issues, see NavMeshAgent Stuck on Edge. For bake failures, NavMesh Building Fails on High-Poly Mesh.

Navigation window open + Scene view gizmo on + default color. Three switches show the mesh.