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AutoBlend – Easily blend objects in your scene

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Overview

AutoBlend blends meshes seamlessly into their surroundings using a post process pass and a small material graph change.
It will automatically compute blend IDs for meshes, but you can override them per material or per object if needed.

Unlike Runtime Virtual Texturing (RVT), Pixel Depth Offset (PDO), and other meshblend techniques, this effect works on any number of meshes at any position - not just where two surfaces meet.

  • Flexible placement: Works anywhere in the scene, not only at terrain or surface-level intersections.
  • No extra prep: No mesh vertex painting, RVT setup, or additional UVs/vertex data needed.
  • Scales well: Adds very little overhead, so it works efficiently even with thousands of meshes.
  • No compile-time changes: Drop it into existing materials without rebuilding shaders or the project.

Setup

  1. Click the AutoBlend button in the Unreal Editor toolbar to open the plugin window.
  2. Install the plugin by clicking the Install button.
  3. Click Recompile Shaders - this may take a few minutes.
  4. In your project console, run the command r.Lumen.ScreenProbeGather.MaterialAO 0.

Tutorial_OpenPlugin.png

Note: This is necessary to fix some visual artifacts.

  1. Add a Post Process Volume to your level.
  2. Add the M_PostProcess_AutoBlend material under Rendering Features → Post Process Materials.
  3. (Optional) Enable Infinite Extent (Unbound) to apply the effect everywhere. Tutorial_PostProcessMaterial.png
  1. Open your mesh base material.
  2. Add the MF_BlendID material function node.
  3. Connect its output to Ambient Occlusion to enable blending.
  4. Repeat for all materials you want to blend. Tutorial_MaterialBlendId.png

Note: We can multiply AO with Base Color to include ambient occlusion in the final output.

Usage

AutoBlend automatically computes a blend ID for every mesh with the material function applied. The blend ID determines which objects blend with each other. Objects with the same blend ID won't blend, while objects with different blend IDs blend together. You can manually override the blend ID:

  • Per Material Override: Set the Blend ID scalar parameter in the material instance (affects all meshes using that material).
  • Per Object Override: Set Custom Primitive Data [0] in the mesh instance settings for per-instance control.

    Note: You can set blend values in the range of 0-254. Set a blend ID of 255 to disable blending for an object/material that has blending enabled.

Tutorial_ManualBlendId.png

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