Anatomical posing tips

Hiya everybody, Alonso here.

Thought I'd mention a couple of anatomy facts that might help to make your poses a little more believable (if you're going for believable).

It's physically impossible to lift your arm higher then horizontal without also raising your shoulder. (This is because there's a little ridge on your upper arm bone (humerus) that connects to your shoulder blade at horizontal and pushes it up when you go higher)

There's a tendon in your pelvis that tilts your pelvis forwards when you try and reach behind you with your leg.

In a non cartoon human, the rib cage is a fairly solid structure so any bending and twisting is usually happening in the lower back, the neck, and in the shoulders. (so don't try to bend the rib cage in half, bend as far as you can with shoulders and stomach and neck.) So make your line of action, but then be aware of where the flexibility comes in when fleshing out the anatomy on top of the line of action. (The shoulders are super bendy, so they often disguise how stiff the rip cage is, because they cover the top part of it)

hope that's useful to some of you. :)

(sorry for my weak tablet drawings, but it's easier to jot out a sketch then find a suitable copywrite free image, so don't trust my crappy drawings stand up and test this stuff out on your own body, or do an image search for yoga and draw on top of it)

Aug '09 Oh, update! check the comments to see what my mom has to say :)

Ian Here - I like this post so much I'm adding it as a resource to the character posing section, thanks Alonso


Ian said...

Weak Tablet Drawings?!?!?!? I think NOT.

Awsome post Alonso. And great advice.

It touches on something I've been thinking about a bit of late, that is the idea of a 3D rig being "off model".

I won't elaborate here though, I'm chewing on it for a future post :)

Thanks so much for posting.

Frank said...

Hey Alonso

Great post. Thank you so much. Excellent diagrams.

You touch on a few points that may lead us off into different directions.

The first being 'realism' in animation and its seeming conflict with the animation principle of Exaggeration. I think that would be an excellent post at some stage - the whole thing about how animators have the potential to make realism more entertaining and appealing without totally flipping Sir Isaac Newton and Henry Gray (Gray's Anatomy) in their respective graves.

Then there is the serendipity that your post occurs at the same time my first year animators are discovering 3D software and posing biped character rigs. I hope they read your post (AND leave a comment ;) ). There are some really useful and important points you make.

Here are some first years having fun posing Max for Maya for the first time: Sarah, Corey, Tim, as examples.

The rest of the crew's efforts can be seen linked from here.

Alonso said...

Cool work by the class :)

Yeah, with rigs getting more and more stretchy as we inch back towards our 2D roots, staying on model becomes a concern again.

Exaggerating is one of the great fun things with animation, turning a character into a deflating balloon or anything you can imagine. The advantage of course of knowing some anatomy is that you can avoid drawing attention to things you don't mean to (like raising the arms above the head without the shoulders is gonna look funny and draw attention, so hopefully you mean to draw attention to that place) Definitely worth more exploration.

The Loud One said...

Hi Alsono

This post comes at a creeeeepy time, as i -and my class- are just starting to venture into the world of 3d. Just this week we've started playing with posing a rig, and it's been an adventure finding out the the limitations that can be found in a rig and how hard it is to create a believable yet striking pose without turning it in on itself or dislocating a limb.

Thank you for a wonderfully timed and educational post.

Alonso said...

hey just ran across this old one from Keith Lango that talks about pushing poses but still respecting anatomy. here

oh, and some advice to students (and everyone) don't let the shiny computer make you forget what you already know. It's easy to get distracted by the 3D space and free inbetweens, but the final image is going to be 2D. It takes time to pose things out in the box, if you have a plan in mind (like thumbnails and notes) you have a a roadmap to get there faster with fewer detours. Oh, and don't take no guff from that computer box, don't be afraid to rip joints out of their sockets, or bend them in totally funny ways, if it gives you the look you want, the final 2D image is what matters, not the integrity of the rig.

Terry said...

Great post Alonso, and I find that previous comment from you to be particularly profound (re: the final image being 2D, even if you're working in 3D software). Thanks.

Alonso said...

ha ha, my physical therapist mother just told me I'm wrong, partly. If you rotate your arm palm up (like flexing your bicep) then you disengage the bones and can raise your arm past horizontal without lifting the shoulder (for a little bit more distance at least)

Illiopsoas and a quadraceps are the things restricting your pelvis (dancer's call it the y tendon) but regular walking you can reach back about 45 degrees before you start tipping your pelvis

-thanks mom