Northbound/TROUBLESHOOTING_GHOST.md

Building Ghost Preview Troubleshooting

FIXED: Preview Activated But Not Visible

If console shows "Preview activated" but you can't see it, this was a material/transparency issue.

Solution implemented:

• Better material creation supporting both URP and Standard RP
• Proper transparency setup for ghost materials
• Multiple material slots handled correctly
• Auto-creates debug cube if prefab has no renderer

Test the fix:

1. Press Play
2. Press B to enter build mode
3. Move mouse over ground
4. You should now see a green transparent ghost of your building
5. Invalid positions show red transparent ghost

If still not visible after update, continue with checklist below.

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Quick Checklist

Run through these checks in order:

1. Check Console Logs

Press B to enter build mode and look for these messages:

• ✅ "Entered Build Mode"
• ✅ "[BuildingPlacement] Created preview: BuildingPreview"
• ✅ "[BuildingPlacement] Found X renderers"
• ✅ "[BuildingPlacement] Applied valid material to preview"
• ✅ "[BuildingPlacement] Preview activated at (x, y, z)"

If you see errors:

• ❌ "BuildingManager.Instance is null" → Go to Step 2
• ❌ "No buildings available" → Go to Step 3
• ❌ "Prefab is null" → Go to Step 4
• ❌ "Preview deactivated - no ground hit" → Go to Step 5

2. Check BuildingManager Setup

1. In Hierarchy, find "BuildingManager" GameObject
2. Verify it has:
   • BuildingManager component
   • NetworkObject component
3. In BuildingManager component:
   • Grid Size: Should be > 0 (e.g., 1)
   • Ground Layer: Should be set (e.g., "Default" or "Ground")
   • Available Buildings: Should have at least 1 BuildingData

Fix: If BuildingManager doesn't exist, create it:

• Create Empty GameObject → Name: "BuildingManager"
• Add Component → BuildingManager
• Add Component → NetworkObject
• Configure settings

3. Check BuildingData Asset

1. Project window → Find your BuildingData asset
2. Select it and check Inspector:
   • Building Name: Should have a name
   • Prefab: Should be assigned (not "None")
   • Width/Length/Height: Should be > 0
3. Verify this BuildingData is in BuildingManager's "Available Buildings" list

Fix: If BuildingData missing:

• Right-click in Project → Create → Northbound → Building Data
• Assign a prefab
• Add to BuildingManager's Available Buildings list

4. Check Building Prefab

1. Find your building prefab in Project
2. Open it and verify:
   • Has a MeshRenderer or SkinnedMeshRenderer component
   • Renderer has a Material assigned
   • Has a Collider (for placement validation)
   • Optionally has NetworkObject (will be removed from preview)

Fix: If prefab is missing components:

• Add a 3D object (Cube, for testing)
• Save as prefab
• Assign to BuildingData

5. Check Ground Layer

The preview won't show if the raycast can't hit the ground.

1. In Scene view, select your terrain/ground
2. Check its Layer (top of Inspector)
3. In BuildingManager:
   • Ground Layer mask should include this layer
4. In BuildingPlacement (on Player):
   • Ground Layer mask should match BuildingManager

Fix:

• Set terrain Layer to "Default" or create "Ground" layer
• In BuildingManager/BuildingPlacement → Ground Layer → Check "Default" (or your ground layer)

6. Check Camera

1. Verify Camera.main exists in scene
2. Camera should be able to see the ground

Fix:

• Make sure Main Camera has tag "MainCamera"
• Camera should be positioned to see the scene

7. Check Player Setup

1. Find your Player prefab
2. Verify it has:
   • BuildingPlacement component
   • Ground Layer is set
   • Max Placement Distance > 0 (e.g., 100)

8. Visual Check in Scene View

1. Press B to enter build mode
2. Open Hierarchy window
3. Look for object named "BuildingPreview"
4. If it exists:
   • Click on it
   • Check if it's active (checkbox next to name)
   • Look at its position in Inspector
   • Switch to Scene view and look for it
   • Check if materials are assigned in Renderer component

9. Test with Simple Cube

Create a minimal test setup:

1. Create a Cube in scene → Save as Prefab → Delete from scene
2. Create BuildingData → Assign Cube prefab
3. Add to BuildingManager → Available Buildings
4. Create a Plane → Position at (0, 0, 0)
5. Press Play → Press B → Move mouse over Plane

You should see the transparent cube preview.

Common Issues

Preview exists but is invisible

Cause: Materials not rendering or transparent issues Fix (Now Automated):

• The system now auto-detects your render pipeline (URP or Standard)
• Creates proper transparent materials automatically
• If prefab has no renderer, adds a debug cube

Manual Test:

1. Add GhostMaterialTest component to any object with a renderer
2. Press Play
3. Object should become transparent green
4. If it works, the ghost system will work too

Preview doesn't follow mouse

Cause: Ground layer not set correctly or no ground detected Fix:

• Check console for "no ground hit" message
• Verify Ground Layer includes your terrain
• Increase Max Placement Distance
• Make sure you're pointing at ground, not sky

Preview spawns at (0,0,0) and doesn't move

Cause: Raycast not hitting ground Fix:

• Same as above - Ground Layer issue

Materials are black/pink

Cause: Shader/material issues Fix:

• Make sure you're using the correct render pipeline shaders
• Standard RP: Use "Standard" shader
• URP: Use "Universal Render Pipeline/Lit" shader

Debug Commands

Add these temporary debug lines to check:

In CreatePreview() after instantiation:

Debug.Log($"Preview position: {previewObject.transform.position}");
Debug.Log($"Preview active: {previewObject.activeSelf}");
Debug.Log($"Renderers: {previewRenderers.Length}");

In UpdatePreviewPosition():

Debug.DrawRay(ray.origin, ray.direction * maxPlacementDistance, Color.red);

This shows the raycast in Scene view (red line from camera to mouse).

Still Not Working?

Check these final items:

1. Input Actions are set up (ToggleBuildMode, Rotate, Build)
2. BuildingManager is spawned on network (in scene, not prefab)
3. You're the owner of the player (IsOwner = true)
4. No errors in Console
5. Build mode is actually active (check console for "Entered Build Mode")

If all else fails, check the Console for any errors and share them!