Hi anthony - MoI actually does already use double-precision floating point numbers which are 64-bit values. The issue about your little segment combined to a much larger profile is not a problem due to non-64-bitness, it's a problem of finding a good tolerance value for fitting operations that does not fit things with too dense or too loose results. Making a mix of a much smaller sized segment along with a larger one for the same surface operation makes it difficult to use one tolerance value for the whole operation. And stuff like using multiple tolerance values for different parts of a calculation can quickly lead to very complex UIs where you do things like tag a bunch of things with esoteric tolerance values for every step that you try to do things...

Anyway - re: continuity and this particular shape you're building - really I would recommend doing things that you want to be smooth like this all as one big long surface rather than trying to do it in chunks like you are doing now.

If you did it as one long sweep or network instead of one bit at a time, it would avoid any need to mess with continuity related stuff at all...

Usually for stuff that you want to be broadly smooth and look like one continuous shape, building it as a larger piece all in one surfacing operation is the best method.

- Michael