FastMeshCopy

Zero-allocation copying of Meshes using the new MeshData functionality in Unity 2020.1+.

The code comes in the form of the static class FastMeshCopy with the

public static void CopyTo(this Mesh inMesh, ref Mesh outMesh){...}

and

public static Mesh CopyReplicate(this Mesh mesh, NativeArray<float4x4> matrices) {...}

extension methods.
Simply call this method on a Mesh instance to perform either a Single Copy, or a Multi-Copy based on an array of transformations + Merge.

Add as a Unity Package

Add this line to your Packages/manifest.json file

"ulc-tools-fastmeshcopy": "https://github.com/GeorgeAdamon/FastMeshCopy.git?path=/UnityProject/Assets/FastMeshCopy#master",

Usage of the Single Copy example

• Attach the MeshCopyExample.cs to a GameObject, and reference a Mesh in the inMesh field.
• Run the game, and press the Spacebar to perform the mesh copy.

Limitations

Accessing BlendShapes and BoneWeights without GC allocations is not supported by Unity's API, so this zero-allocation effort ignores them for the time being. See the discussion

Performance Example

Copying of a 98 MB mesh, creating only 80 Bytes of allocations for the Garbage Collector to clean-up.