Fix: Unity Procedural Mesh RecalculateNormals Too Slow at Runtime

Procedural cave system regenerates meshes. RecalculateNormals consumes 60% of the regen budget.

Burst job implementation

Custom IJobParallelFor that computes per-triangle normals, then averages per-vertex. ~10x faster than RecalculateNormals.

Or precompute

If the mesh deforms but topology is fixed, precompute the normals; transform in shader. No CPU cost.

Use SetNormals bulk

Avoid vertices[i].normal = .... Build a NativeArray; call SetNormals(arr) once.

“RecalculateNormals is built-in convenience. Convenience scales until it doesn't.”

For procedural mesh work, build a Mesh utility library with Burst-jobbed versions of RecalculateNormals, RecalculateTangents, RecalculateBounds. One-time investment; permanent payoff.

Related reading

• Fix: Unity Shadergraph Vertex Displacement No Recompute Normals
• Fix: Unity Shader Graph Procedural Uv Noise Banding
• Fix: Unity Shader Graph Procedural Grid Aliasing
• Fix: Unity Mesh Collider Cooking Options Slow Load