Hi all,
I am interested in 2d skeletal animation(aka. bone animation) recently, and find some simple 2d skeletal animation editor. But I found that it's difficult for me to create real and natural character animation. I want to know how to create real human 2d skeletal animation easier, does it require the animator appointing every keyframe bone posture manually? Is there any better method except Motion Capture(because it's expensive ^^)?

Can anyone give me some hint? Thanks in andvance!

Hmm, no replies to this? Well, first suggestion is video is useful even if it's not motion capture. You can get a video clip or film yourself, and break it down into frames, then use those as guides for your animation keyframes.

This is the bible of animation:
http://www.amazon.com/Illusion-Life-Disney-Animation/dp/0786860707

This book is almost as good:
http://www.amazon.com/Animators-Survival-Kit-Richard-Williams/dp/0571202284

Here is the cliff-notes version:
http://en.wikipedia.org/wiki/12_basic_principles_of_animation

Some details will apply to your project, some won't. But overall, these are the things that are covered in animation classes.

Thank you, sunandshadow and MSW. Your instructions are useful for me.

I would say MSW's list is flipped, but good none-the-less. Both books are absolutely fantastic. Illusion of Life spends more of the book expounding upon the history of Disney, whereas The Animator's Survival Kit is a little more to the point and has more references than just Disney films. The history in Illusion of Life is incredibly rich and interesting though.

As far as had animating every key-frame, not really. You setup your rig with FK and IK controls, which does a lot of the calculations for things such as if the animator puts the hand here, then this is where the elbow goes. The animator can make manual additional adjustments from there, but the modern 3d toolsets have some pretty awesome rigging systems.