It looks like Poser does have a potential solution to this problem built in, although I've never seen the matter discussed anywhere before.  :unsure:

Smoothing groups.  By using the Grouping Tool to define which polygons to smooth with one another, the problem seen above seems to be controllable.  Smoothing groups are a well-hidden solution, and not terribly well explained.  They seem like they may be necessary now, at least on some geometries, so they really should be talked up loudly to the user base.  But they are kept a secret.  Umm.

The Reference pdf does not specify whether a Smoothing ID assigned using the Grouping Tool should be numeric.  The input accepts letters as well as numbers, but I didn't notice any effect on my object when I tried smoothing groups named as words.  Using numbers, they seem to have kicked in.  This is perhaps another point that should be clearly explained to users, particularly if this feature has now become important in order to compensate for oddities in Poser's bizarre auto-smoothing routines.

Smoothing groups are apparently not connected to "Smooth polygons", which also seems to be unexplained.  The smoothing groups help me get rid of the ugly artifacts I have shown above, but do nothing to prevent an object from ballooning out when "Smooth polygons" is checked.

If setting the obj edges as "hard" doesn't help and crease angle alterations aren't proving useful, I guess we should try smoothing groups now before resorting to slicing up an object's geometry to control polygon smoothing.  We do have plenty of options!  :lol:  Call me silly, but I'd prefer a rendering engine which doesn't do weird things and requires no extra tweaks like this to having all the options.  Umm.  :unsure:

===========================sigline======================================================

Cage can be an opinionated jerk who posts without thinking.  He apologizes for this.  He's honestly not trying to be a turkeyhead.

Cage had some freebies, compatible with Poser 11 and below.  His Python scripts were saved at archive.org, along with the rest of the Morphography site, where they were hosted.