| 1680 | 
  | 
directs the use of a scene description. | 
| 1681 | 
  | 
<ul> | 
| 1682 | 
  | 
<li> | 
| 1683 | 
< | 
<a NAME="rview" HREF="../man_html/rview.1.html"><b>Rview</b></a>  is  ray-tracing  program  for  viewing  a  scene interactively.    | 
| 1684 | 
< | 
When  the user specifies a new perspective, rview quickly displays a rough image on the  terminal,   | 
| 1683 | 
> | 
<a NAME="rvu" HREF="../man_html/rvu.1.html"><b>Rview</b></a>  is  ray-tracing  program  for  viewing  a  scene interactively.    | 
| 1684 | 
> | 
When  the user specifies a new perspective, rvu quickly displays a rough image on the  terminal,   | 
| 1685 | 
  | 
then progressively increases the resolution as the user looks on. | 
| 1686 | 
  | 
He can select a particular section of the image to  improve, or  move  to  a different view and start over.   | 
| 1687 | 
  | 
This mode of interaction is useful for debugging scenes as well as determining the best view for a final image. |