Renderd and build in Houdini, this is a network I setup to generate procedural layers of tubes onto a main tube.
It UV-maps the pipes and should avoid intersection to some degree.
I have setup controls for things such as "corner width", smoothing of the pipes, how much detail it has and so on.
The layerd pipes have a min/max radius value that is randomized for each layer.
There is a little demo video on the right section showing how the layerd tubes work.