<World>
   <Camera eye="0, 0, 10" look_at="0,0,0" fov="30" />

   <ShaderGroup>
      shader envmap layer1;
   </ShaderGroup>
   <Background resolution="1024" />

   <ShaderGroup>
      param float roughness 0.25;
      param color Cs 0.5 0.5 0.5;
      shader sheen layer1;
   </ShaderGroup>
   <Sphere center="0,0,0" radius="1.0" />   
</World>
