is accurate joint placement crucial for realistic rig

#1

Hello,

i am trying to rig a very realistic character. I was wondering when i place the joints shoulder their position be accurate to exactly where the joints would start and stop in a real person. Presumably they do, because the pivot point is affecting where the leg or arm bends from.

Also for the spine, for a realistic contortion of the spine, should there be as many joints as would be vertebrae in the human back. If not how many are ideal?

could someone help me understand this, or maybe recommend a tutorial series or training that is useful for this type realistic rigging.

thanks alot,
Sam

#2

Yo,
dont know any tutorials about this but, yes, anatomical joint placement is extremely important if you want to produce realistic results. (Well, as realistic as you can get with just skinning).
Biggest areas where I see violations of that is hips and clavicle/shoulders. And then people wonder why those areas look like crap. Grab an anatomy book or google, and youll find all your positions.
As for spine, yes you could use a bone per vertebrae, but thats just overkill. In my own rigs my spine is only 6 joints, 1 is hip, 6 is base of the neck. Works pretty well already. In that case the spacing of the joints is also very important tho. Have a few more bones on the lower end of the spine, and only 2 up in the chest region to get slight bends, but have it remain mostly rather rigid. You could then just sample a bunch of more dense joints from that.

#3

cool, thanks for the help

i saw some people do an extra few joints for the clavical and scapula. But that area of the shoulder is very confusing to me.

also how come you use 6 joints for the neck? should you get enough with maybe 3?

thanks,
Sam

#4

haha, nop, I dont use 6 bones for the neck. spine joint number 6 is at the base of the neck. Thats how I meant.

#5

Hey there,

yeah accurate placement and understanding of joints is key to good rigging. It can make the difference between a bad, high tech and a good low tech rig.

The shoulder area is quite complicated at first, as there is no “real” shoulder joint, rather as a system of joints from scapula, clavicula and humerus that works together and is activetd by a set of muscles. It´s called “rotator cuff”. Once you get the hang of that, things start to get easy however

I´ve created a set of animations detailing muscles and anatomy for a client in the medical sector. You can find it here:

http://flexikon.doccheck.com/de/Schultermuskulatur

While being in german, it´s got lots of WebGL examples and a ton of 3d information videos.

Hope it can help you.

Chris

BTW: 6 joints for the spinal area is enough for most rigs, However, if you want a correct deformation for the rib cage you might think about using more spine joints, as the ribs run from the spine to the sternum and need the spinal joints to run correctly.