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Before starting this tutorial, read Working with Data to understand Groups, Resource Types, and Prototypes.
Texture Stamper is a MonoBehaviour stamper tool that paints Unity Terrain texture layers across a defined area. Instead of painting manually with a brush, it evaluates Mask Filters for each texture prototype and writes alphamap data to the terrain at once.

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Step 1 — Add a Texture Stamper to your scene

Go to GameObject > MegaWorld > Add Texture Stamper. A Texture Stamper component is added to a new GameObject in your Hierarchy. Its Transform scale defaults to (150, 150, 150), which sets the initial stamper area size.

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Step 2 — Add a Group with Terrain Texture prototypes

Select the Texture Stamper in the Hierarchy. In the MegaWorld Window, click Add Type to create a new Group. Inside the Group, click Add Resource and choose Unity/Terrain Texture as the resource type. Drag your TerrainLayer assets from the Project window into the prototype list.
TerrainLayer assets are created in the Project window via Create > TerrainLayer. Each TerrainLayer holds a texture, normal map, and tiling settings. The terrain must already have the TerrainLayer assigned to it before Texture Stamper can paint it.

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Step 3 — Configure Mask Filters

Select a prototype and expand its Mask Filters settings. Mask Filters determine where and how strongly each texture is painted. Common setups:
  • Slope filter — paint rock textures on steep slopes and grass on flat ground.
  • Height filter — snow at high elevations, mud at low elevations.
  • Noise filter — add organic variation to texture boundaries.
If you do not add any filters, the texture is painted uniformly across the full stamper area at full strength.

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Step 4 — Set the area size

The stamper area is controlled by the Transform scale of the Texture Stamper GameObject. Scale it in the Scene View to cover the terrain region you want to paint. You can also click Fit To Terrain Size in the Area Settings section to match the active terrain’s dimensions exactly.

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Step 5 — Stamp

In the Stamper Tool Controller section, click Spawn. The Texture Stamper evaluates each active prototype’s Mask Filters and writes the results to the terrain alphamap. To preview the filter output before stamping, enable Visualisation in the Stamper Tool Controller. When a single Group is selected, the Scene View shows the filter coverage as an overlay.

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Step 6 — (Optional) Enable Auto Respawn

Turn on Auto Respawn in the Stamper Tool Controller to automatically re-run the texture pass every time you change a filter setting. Use Delay Auto Spawn (range: 0–3 seconds) to add a short wait before each respawn triggers, so it does not run on every keystroke. Auto Respawn is not available when Use Spawn Cells is enabled.

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Step 7 — (Optional) Use Spawn Cells for large terrains

If your terrain is larger than approximately 4 km × 4 km, enable Use Spawn Cells in the Area Settings. This divides the stamper bounds into a grid of smaller cells and processes each one separately, which prevents long freezes.
  1. Enable Use Spawn Cells.
  2. Set Cell Size (default: 1000 meters).
  3. Click Refresh Cells to generate the cell grid.
  4. Click Spawn to process all cells in sequence.

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What’s next

  • Add multiple Groups to layer different textures across the same terrain area.
  • Combine Texture Stamper results with Terrain Spawner vegetation passes.
  • Read the full Texture Stamper reference for all settings.