title: disable rotation of shape
body: <p>I have two shapes and I want to disable the rotation of one of theme. What's the best way to do that? </p>
  
  <pre><code>    # A Cylinder
   Shape {
       appearance Appearance {
           material Material {
      diffuseColor 0.75 0.5 1.0
              specularColor 0.7 0.7 0.8
              shininess 0.1
           }
       }
       geometry Cylinder {
           height 0.2
           radius 3.
       }
   }
  # A Sphere
  Shape {
       appearance Appearance {
           material Material { 
           diffuseColor 0.2 0.5 0.75
           transparency 0.0
       }
       }
  geometry Sphere {
      radius 1.0
  }
  }
  </code></pre>
  
  <p>Thanks</p>