Quote -
It has nothing to do with Wings3D' s tolerance. The mesh goes through several steps of post-processing, during which the numbers get rounded. I thought six decimal places would be more than enough. Apparently I was wrong.

Oh, OK, I see what you're saying. I never tried Wings though, so I wouldn't have known how you do it.

Quote -
MikeJ: Thanks for trying that out. I'll just add a few more decimal places in the obj file then.

It would be great if the same effect were responsible for the problems in Poser, particularly if the symmetry feature works for other figure. I'll have a look at that as well, but as I said, Poser does strange things, and it might be something different entirely.

Well you're welcome. Anything I can do to help, you know. :-)
As for Poser, I'd have no idea. In fact, I tried the split morph thingamabob once before, a good while ago. It didn't work, and I never even thought about it again until now, in this situation.
I'd bet it works only with the CP/SM figures, if I had to take a guess.
I do most definitely understand the "Poser does strange things" part though. ;-)