"Blend zones" are where two body parts meet.
The polygons of both zones must be deformed so that the result is still a smooth mesh and will render properly.

Blend zones can be adjusted using Poser's "Joint Editor."
It is a rather complicated process and if you want to attempt it, MAKE A COPY OF A SIMPLE FIGURE (P2 or P3), and "play" with that figure first to see what you're getting in to.

cheers,
dr geep
;=]

Remember ... "With Poser, all things are possible, and poseable!"

cheers,

dr geep ... :o]

edited 10/5/2019