The curve feature was designed to get animals' tails right. See e.g. the Poser horse's tail. The curved limb / tail / tentacle would have to be divided into at least 5 segments of equal length. My flamethrower's model fuel hose has 8. - If the limb/etc necks off at one point, curse all Poser bugs and move that joint a bit. - If kinks or gaps develop at the inner or outer end of a chain of curved segments, interpose a very short extra non-curve non-rigid segment.