Hi Brian, it looks like the problem is the tubes are not well formed, they have some areas where parts of them are kind of bunched up and self-intersecting:








When a surface bunches up and intersects itself in that way, it will usually prevent the booleans from working successfully.

In this case, it looks like you had a radius for the tube that was larger than the radius of the bend it was going around. That will produce this kind of bunching problem.

Here's another illustration that may help to explain.

Here there is a line (similar to the tube radius in your model) that is trying to move along a path curve, around a bend that is tighter than that distance:



As it moves, you can see that the result is not clean , there is a bunching and self-crisscrossing that will happen:



You've got that same kind of thing happening in your model as well.


You'll need to get a tube without those kinds of self-intersections in them in order to use them in booleans. There are a few different alternatives, possibly building the tubes in sections rather than as one long piece, or with a smaller radius, or with not as tight of a bend in those areas.

- Michael