Pointers to volume-line intersection calculation?

[Dirk.Craeynest@eurocontrol.be (Dirk Craeynest)]

We are looking for pointers to literature, algorithms and/or code
(preferably in Ada) for the *efficient* calculation of the intersection
of lines and volumes in 3-dimensions.

For our project, we need a.o. to calculate the "air-spaces" that the
route of an aircraft crosses.  We thus have
- on the one hand a list of points on/above the earth surface, with
  segments of the route in between (in a first approximation straight
  lines, but in fact curves that take into account the curvature of
  the earth surface),
- and on the other hand volumes that cover the complete surface of
  Europe (at different altitudes).

As this kind of problem is undoubtedly solved in other software, we
would appreciate any reference that allows us to reuse already existing
code.

Thanks in advance for any help.

--
Dirk Craeynest |                         | Email: Dirk.Craeynest@
   OFFIS NV/SA | c/o Eurocontrol - CFMU  |        eurocontrol.be
   Ada-Belgium | Raketstraat 96          | Phone: ++32(2)729.97.36
   Team Ada    | B-1130 Brussel, Belgium | Fax:   ++32(2)729.90.22