C++でRustみたいなFrom<T>, TO<T>を実装する方法

// 外部APIなどの構造体
struct dim3 {
  unsigned int x;
  unsigned int y;
  unsigned int z;
};

struct Dim3 {
  unsigned int x;
  unsigned int y;
  unsigned int z;

  // to<dim3>
  operator dim3() const {
    return {
        .x = x,
        .y = y,
        .z = z,
    };
  }

  // From<dim3>
  explicit Dim3(dim3 dim) : x(dim.x), y(dim.y), z(dim.z) {}
};