If it is just a simple triangle strip (with no degenerate triangles or edges) then it is possible to figure out which face(s) a vertex is adjacent to, with a simple formula.
Remember that the first vertex is only a member of the first face, the last vertex is only a member of the last triangle. The second vertex is a member of the first two faces, the second to the last vertex is a member of the last two faces and every other vertex is a member of three faces, such that for vertex n, faces (n-2), (n-1), and n are adjacent. (I think at least, I haven’t fully awoken yet. So double check my math.)
[This message has been edited by DFrey (edited 02-11-2001).]