ZBrushCentral

Dominiek's Sketches.

Hi,

Long time since I posted anything.
I’m really back into ZBrush and am doing mostly anatomical studies.
This one I want to share with you as it is my first asymmetrical sculpt ever.
Took me most of the day, considering some of you people do this in half an hour and much better, LOL.
Anyway, I’m having fun with ZBrush …

Attachments

ZBC.jpg

Hi there,

Continuing with anatomy : started with Ryan Kingslien’s ZTool, made a ZSpheres skeleton, skinned it and took a few parts from the original, then dynameshed away.
It was a great learning experience and the fact that I’m able to do this proves that ZBrush is ‘simply’ awesome!


A bit about the process :
ZBC_Woman_2.jpg

Refined the previous sculpt : still a WIP and in Dynamesh mode :


ZBC_Woman_4.jpg

Hi,

My latest sculpt is based on the work of Alena Wooten (Blog : http://alenawooten.blogspot.be/ ) and rendered in Modo.

ZBC_Browny.jpg

awesome!

@ milivoj_popovic : Thank you very much!

Continued with the previous refined anatomy sculpt and found some inspiration online :
turned her into Ms. Marvel (Based on a sculpture by T. K. Miller - http://www.tkmiller.com/index.html ) :

Ms_Marvel_Modo_Render_001.jpg

Quickie speed sculpt for practice : caricature of a well known body builder : do you recognize him?

Another study : based on Loomis.

For a long time I have wondered about the Pronation and Supination of the forearm.
It has been clear to me for a long time that the the Radius rotates along its own axis so that the forearm can rotate.
But it never became clear to me what exactly the Ulna does when the forearm twists, until now (I hope, LOL).
The reason for this is that the Ulna does SEEM to rotate on the hand-side when you twist the forearm, but not at the elbow-side.

The Ulna actually does rotate a bit at the elbow-side : but not the same way as the Radius : the Radius rotates around its AXIS-length and the Ulna
rotates perpendicular to its AXIS-length a bit : IMO that is why the Ulna seems to rotate at the wrist-side.

And with the help of an image on this website I finally got it (I believe) : LINK : http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Articulations/supination_pronation_labeled.jpg

I’ve attached my own image that hopefully illustrates things better.

Hope you find it useful.

And of course please correct me if this is wrong.

_Ulna_Radius_Pronation_Supination.jpg

Thats a cool illustration and a tricky subject! Hmm maby you should look into the subject further before coming to conclusion. Do not trust wikipedia or any other of the free info online since most of it is copy-paste. Instead, go to a medical library and look up books on Kinesiology. In those books you will find hundreds of pages about this movement specifically.
Keep in mind that the Humeroulnar joint does not move sideways (the joint does not permit that). Instead, what usually happens, naturally, is that the humerus will internally rotate and/or abduct a bit (at the Glenohumeral joint) to “help” the forearm with the pronation-movement, which results in the head of the ulna “moving” while pronating.
Books on artistic anatomy are not to be trusted when it comes to information like this, simply because it is too specific. PM me if you recommendations on books.

Kindly,
Alexander

Thanks Alexander!

I’ve been wondering about this for years, but never actually got deeper into it.
Today was one of those days that the idea would not let me alone and it was actually the image on the link above ( http://biology.clc.uc.edu/fankhauser/Labs/Anatomy_&_Physiology/A&P201/Articulations/supination_pronation_labeled.jpg )
that did it for me : when you look at the two images you can clearly see a gap between the capitulum and the ulna when in pronation, and
not so in supination, and the “hollow” form of the ulna actually allows for the kind of rotation that I’m describing, so that is the only explanation
I’ve been able to find that explains why the ulna appears to be rotating like the radius.

Would love to talk about that with an expert, because indeed anatomy books do not cover this in deep, and two-dimensional images only can learn you so much.
I’ve seen Youtube videos on the subject matter but in those they use 3D models, which is also not very accurate.
I’ve been reading on websites for radiologists and colleges and such but have not really found what I’m after.

What I’ve initially learned years ago is that the ulna does not rotate at all : I know this has to be wrong from experience : just hold your elbow, rotate your forearm in a way
that the hand keeps “occupying the same space” : you’ll see that the ulna has to rotate somehow otherwise your hand would not be able “to occupy the same space” : your
hand would be like rotating around the axis of the ulna if you know what I mean.
And I’m not talking about the rotation of the humerus : I’ve tested it with my elbow pressed against the table so I would not be able to rotate my upper arm.

So seeing that above mentioned gap between the ulna and the capitulum and looking at the form of the ulna at the capitulum I was thinking that my description is the only
possible way that the ulna can rotate, since it is impossible to rotate the ulna along its length axis (without breaking it), it has the able to rotate perpendicular to that axis, otherwise
your hand would not be able “to occupy the same space” when twisting your forearm.

Any further info is of course most welcome.