This is my code:
//no effect
surfaceTool.SetSmoothGroup(uint.MaxValue);
surfaceTool.Begin(Mesh.PrimitiveType.Triangles);
//no effect either
surfaceTool.SetSmoothGroup(uint.MaxValue);
//doesnt work either:
//surfaceTool.AppendFrom(arrayPlane, 0, Transform3D.Identity);
surfaceTool.CreateFrom(arrayMesh, 0);
surfaceTool.GenerateNormals();