Ok. Here is my RD nemisis. This applies to Carrara also.
Sounds simple, but it is not. Using the Freeform Modeler,
how can one animate a tube precisely through a seperate compound curved tube. This is a compound a snaking motion.
The fit must be precise. The length of the inner tube must essentially remain constant.
The turns must not get out of slither. Each section must take the place of the one that precedes it.

I have done alot of faking with passable, but not perfect results.

Typically I use a cylindrical freeform with as many sections
as there are curves. The problem is with getting the sections to advance sequentially and consistently through each curve .Ideas?