[ REQ 6016]: how do I color a collection of surfaces?

[linhong at cs.arizona.edu]

Dear Geomview software team:
 I am writing an external module for Geomview to display water shed for
  a given terrain represented by TIN surface approximation. In other
words, if mouse pick up a surface of an object, I need to display the
surfaces which drain into the picked surface. I have problem in
displaying a surface(they are all three dimension triangles). I
basically used the example3 in your external module example. If I pick
world coordinate, and pick the surface index, how do I communicate with
geomview in order to color the surfaces? I tried to let Geomview to read
 my OFF file(contains data for the triangle surface), but nothing shown
 up. I noticed that the picked coordinates are in world coordinates but
 my original data is in self coordinate, how do I transform them?
 any help is appreciated.
   your scinerely,
   hong

my email: linhong at cs.arizona.edu