Hi,
I used the flying through pipes set up only a couple of months ago, they way I performed it was as follows.
1: Create pipe in 3dsMax and make it the length you require.
2: Use deform tool to create bends/kinks in it.
3: Add desired material (i used a hi res dirt pic)
4: Make camera in 3ds and postion light within the tunnel spaced for even lighting
5: key frame camera along tunnel rotating and pitching for organic flight feel
6: save out animation (using png filetype and retaining alpha channel
7: import phg sequence into after fx for post adjustments.
8: Live happiy ever after
also Andrew Kramer deal a little in this type of thing in a 3d room tutorial he did at video copilot. You could adapt that to suit if your tunnel does not need to be rounded…
I use that second method on the opening sequence for this clip
https://www.youtube.com/watch?v=nP0niYDDXZg
salutations from codemonkey