The following piece of pseudo-code describes the format found in a segment file:
c.....nmax is the number of segments c.....ni(n) is the number of points on segment n c.....imax is the number of points
integer ni(nmax) real x(imax), y(imax), z(imax) do n = 1, nmax write(1,*) ni(n) do i = 1, ni(n) write(1,*) x(i,n), y(i,n), z(i,n) end do end do