title: 3d grid adapted to non rectangular data in gnuplot
body: <p>I would like to plot points in a 3d plot and create a mesh that could handle non rectangular data. To be more specific my data is</p>
  
  <h3>data.dat</h3>
  
  <pre><code>-1 0 0
  -1 1 0
  0 -1 0
  0 0 0
  0 1 0
  1 -1 0
  1 0 0
  </code></pre>
  
  <p>and my gnuplot file</p>
  
  <h3>plot.plt</h3>
  
  <pre><code>set dgrid3d 3,3
  splot 'data.dat' w l
  pause -1
  </code></pre>
  
  <p>Unfortunately <code>dgrid3d</code> seems to make my data rectangular and a rectangular grid (actually a square grid) is plotted. Is there a way to plot a restricted envelope of my data ? Ideally I would like to plot the <a href="http://en.wikipedia.org/wiki/Orthogonal_convex_hull" rel="nofollow">orthogonal convex hull</a> of my set of points.</p>