I weight-painted the knees - and elbows, I think - early on with pretty good results. But then I threw that away because I needed to make some fundamental changes before I could work on the more difficult regions, so I can't show anything right now.

Blender appears to use some magic to make joints look better even without any manual tweaking, but I don't know any details. For the knees, the main issue was making the knee cap keep its shape and move to the correct position, and then there was a little bit of tweaking in the back to get a nice fold. I did some work to improve the topology beforehand, so that may have helped, too.

I'll probably still add a corrective shapekey - what's called a JCM in Poserland - at some point because I'm a perfectionist. :grin:

-- I'm not mad at you, just Westphalian.