title: 3D visualization using R
body: <p>I have a set of values, w, for each (x,y,z). I want to visualize this 4D data as an interactive 3D image plot.</p>
  
  <p>That is, each 3D pixel x,y,z should get some color based on w.</p>
  
  <p>PS: w ranges from 0-7, and the rest of the (x,yz) are just transparent.</p>