Why do rigs never match a real skeleton?

#1

I was just looking at common AAA title game characters, and I noticed that “uncanny valley” feeling in a lot of their joint motions.

And It looks to me (just from an outsiders view who does not animate characters) that the rigs skeleton isn’t a perfect match for a real human skeleton.
Especially around the neck/shoulders area.
it looks as though maybe it’s missing some flex areas, or missing certain joints entirely.

I’d say I notice this in 2/3’s of game characters.

SO i wanted to the experts. YOU GUYS.
When you build a standard human skeleton, do you fit it to your models joints,
or do you EVER start off by literally copying a real human bone skeleton and replacing those bones with digital bones?

Seems like the 2nd idea would be common sense and not that difficult to do.
especially considering you could just do it once and then have a base to reuse and modify for other characters.

Any thoughts?

#2

The complexity of an actual skeleton and muscular system (e.g. in a shoulder girdle) would be very expensive to calculate with a run-time rig used for game engines. Game rigs need to take shortcuts for performance reasons. Riggers do strive for anatomical accuracy much of the time, especially in limb joint placement, but clavicle, spine, and neck joints are often tweaked to provide better skin-solving.

#3

Mostly those joints aren’t on the anatomicaly correct place because most of the time (99%) you can’t use muscles in game engines and some times you cant use even blendshapes on some places, or at all (it’s all up to clients requirements). In order to get nice deformations only with skin you need to adjust joint placement, which for you they look ‘off the correct position’ but for riggers they are on the place where they should be :slight_smile:

Hope this helps you.

Sincerely,
Ar.

#4

perfect. that totally answers my question!!
makes total sense too.