Unity 6.2 MeshLOD Explained

Mesh LOD in Unity 6.2

Unity’s new Mesh LOD system automatically creates and manages levels of detail for meshes on import, reducing polygon count and improving performance with a minimal memory footprint.
Unlike traditional LOD Groups, it doesn’t create extra GameObjects or duplicate meshes — all LODs are stored in the original mesh’s index buffer, reusing the same vertex buffer.

How It Works

  • Runs at model import time, collapsing edges while preserving shape and avoiding visual artifacts.
  • Needs at least 256 triangles to start simplification, and stops if too few remain (~64), if it hits the Limit LODs setting, or if no more vertices can be removed.
  • Each LOD has roughly half the indices of the previous one.
  • Best results on organic or high-density meshes like rocks, creatures, and sculptures.
  • Maximum memory increase is ~100% of the index buffer, far smaller than LOD Groups which duplicate full vertex data.

Generating LODs

  • In the model’s Mesh LODs section, tick Generate Mesh LODs, tweak settings, and click Apply.
  • Import time will increase slightly.
  • Use the LOD slider in the Mesh Inspector to preview results.
  • Not recommended for meshes already using _LODx naming unless required
  • To remove LOD data, untick the box and re-apply.

Runtime LOD Selection

  • Unity picks the LOD based on the object’s screen size.
  • Project-wide control: Quality > Level of Detail > Mesh LOD Threshold — higher values make Unity switch to lower-detail LODs sooner.
  • Per-object control: In the Mesh Renderer’s Mesh LOD section, adjust LOD Override or LOD Selection Bias.
  • Test with different assets and camera movement to balance quality, performance, and smoothness.

Cross-Fading

  • Smooths LOD swaps by blending the current and next LOD with dithering or transparency.
  • In URP: enable LOD Cross Fade in the URP Asset and turn on GPU Resident Drawer.
  • In Built-in RP: enable LOD Cross Fade in Project Settings > Quality > Level of Detail.

Limitations

  • Doesn’t work with: Entities Graphics, Particle System, Visual Effect Graph, static batching, or GPU instancing.
  • Skinned Mesh Renderers ignore skin weights and blend shapes during simplification, and deformation is always based on LOD0 cost.
  • Triangle topology only.
  • No built-in way to visualize the active LOD at runtime.
  • Mixing with LOD Groups is not recommended.
  • Some rendering APIs (Graphics.RenderMesh) need manual LOD selection via forceMeshLod.

Troubleshooting Artifacts

  • Common causes: high curvature, disconnected sub-meshes, aggressive simplification.
  • Fixes:
    • Lower Mesh LOD Threshold.
    • Adjust per-object LOD settings.
    • Use Limit LODs to stop generation before quality drops too far.
    • Switch to LOD Groups for problem meshes.
  • Skinned mesh issues: missing vertices can break blend shapes.
  • Lighting issues: incorrect normals on simplified meshes — use the same mitigation steps.