title: Overlay surface to 3d points
body: <p>Suppose I have a 3D point cloud represented by:</p>
  
  <pre><code>arv = data.frame(axis_x = rnorm(n=300, mean=-0.20, sd=1.01),
               axis_y = rnorm(n=300, mean=-0.45, sd=0.97),
               elevation = rnorm(n=300, mean=-813.2, sd=13.89))
  </code></pre>
  
  <p>And I also have a paraboloid modeled by:</p>
  
  <pre><code>model = lm(formula = elevation ~ (axis_x + axis_y)^2 + I(axis_x^2) + I(axis_y^2), data = arv)
  </code></pre>
  
  <p>Is it some way to plot <strong>both</strong> (the points and model) together in a 3D plot?</p>