Very Computer

I am trying to determine the elevation (the Y coordinate) of
particular points in my terrain database at run-time.  I would
like to have tanks, etc. drive over the database and pitch and
roll accordingly to the changes in elevation.  To do this I
need to know the elevation of the terrain under the tank.

If possible, I would like to avoid searching the entire scene
graph for the polygon under the tank and determining elevation
from there.

My first thought was to use the SoRayPickAction to determine
the elevation.  I would like to cast the ray through to tank
and have it determine the objects below it.  However, I
believe SoRayPickAction uses the viewport and camera positions
which is not what I want.  Any ideas???

Thanks for any help or suggestions.

Wm. Frank Dea
--
Research Engineer
Southwest Research Institute (SwRI)
San Antonio, TX

   start     = SbVec3f (tank_x, 0., tank_z) ;
   direction = SbVec3f (0., 1., 0.) ;
   near      =  0. ;
   far       = -1 ;
   SoRayPickAction::setRay (start, direction, near, far) ;

Quote:> If possible, I would like to avoid searching the entire scene
> graph for the polygon under the tank and determining elevation
> from there.

   SoAction::apply()

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