title: adding or converting between cv::Point3d and cv::Vec3d
body: <p>Since they both have three elements, it seems logical to have a overloaded addition operator to add between the two types. Or would this not make sense from a design point of view?</p>
  <p>But since that doesn't exist, we have to convert <code>Vec3d</code> to <code>Point3d</code> first. <a href="https://docs.opencv.org/3.4/d6/dcf/classcv_1_1Vec.html" rel="nofollow noreferrer">This link</a> mentions there's a way to convert them but I don't see it. The best I could do is something like this:</p>
  <pre><code>void vecToPoint(const cv::Vec3d &amp; v)
  {
      cv::Point3d p;
      p.x = v[0];
      p.y = v[1];
      p.z = v[2];
  }
  </code></pre>
  <p>Thank you</p>