UnityのMeshクラスのvertices、uv、SetTrianglesについての説明で、どんな値を入れると動的にメッシュが作れるかの話になります。法線の設定は説明しません。 先にコードについて こんな感じのコードでX,Y方向に長さ2の平面を作成し、マテリアルを一つ設定できます ...

The VertexPaint tool is designed to allow easy painting of vertex colors onto surfaces within Unity. It can be used to quickly paint lighting into the scene, like this: The easiest way to get started ...

Unity or Unreal engine save the vertex data per instance. That way the mesh remains the same and after reimport the vertex color is not lost. Sometimes it's scrambled if the mesh is too different from ...