Understanding the default skeleton

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Understanding the default skeleton

Postby bowidl » Wed Mar 18, 2020 8:41 pm

Hi,

I don't understand why the default skeleton splits the limb bones in two. The upper arm, lower arm, upper leg and lower leg all consist of 2 bones. Why is that? My best guess is when rotating around the y-axis it helps to evenly spread the mesh deformation across the whole limb to avoid this unrealistic effect you get when rotating close to the limit of the joint? So instead of rotating the upperarm01 for 90°, better rotate upperarm01 and upperarm02 for 45° each? But then, when I rotate my own upper arm, my "mesh" (aka my skin) is only deformed below the shoulder, whereas the skin extending to the elbow is not affected. Can you please explain the reason for splitting the limb bones in two?

Another thing I would like to know is if there exists a reference for how much each bone can be rotated at max around each axis. When I began posing my models in Blender, I used to look at this pdf for guidance: https://www.dshs.wa.gov/sites/default/files/FSA/forms/pdf/13-585a.pdf. But this is pretty vague since I don't know the rest pose they use. (What is the rest pose of a human? Mine would be lying on the couch :D )

And finally, in connection with my last question, would you recommend using bone constraints in Blender? I tried them for a bit, but I gave up on them because when I rotate a bone around a single axis (like pressing r-x-x and moving the mouse), it slightly affects the other 2 axes as well. Also the order in which the bones are rotated is relevant. So eventually I was locking myself out of rotations even though they should still have been possible. So I ditched the constraints.
bowidl
 
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