While there are a lot of 3D libraries out there, I'm in struggle to find one suitable for WPF.
Basically, I want a Character Animation engine, which loads bone hierarchy and allows me to manipulate the skinned mesh.
I know, this is a classic topic for all the 3D engines. And they are made for building games.
How do I display a Skinned Character in a WPF application?
Well you could try this:
If that OGRE engine supports bones, you should be good to go.
More about the OGRE Engine
Good Luck!
Depends on how broadly you want to distribute your app, provide installation support for it - and how much work you want to do
1) You can always do it yourself - but you've probably already decided you don't want to spend 2 years of your life building a render pipeline, learning the vagaries of IK, etc
2) You could target XNA - this is sort of WPF, will run on windows, and the xbox to boot - one package you could consider for XNA is Visual 3D - you can find a list of engines here
3) IFF you either can access the target machines directly, or can release your app as a standalone WPF application, you've got a lot of options - all you need is a C# wrapper that allows you to call a native implementation - the one thing you'll loose is WPF ability to superimpose controls, because your render surface will most likely be a winform control embedded in a WPF UI - you will need to get the wrapper DLL into the GAC if you want to distribute the app broadly -
3a) check out the Blender community - the entire tool is open source, and there's a lot of smart people playing in that space
4) I'd tout my own engine but it's undergoing a thorough revision and won't be out again for quite a few months - we'd provide WPF/Silverlight support via option 3 - .Net wrapper over C++ core directly installed into GAC - which makes it available for WPF/Silverlight - I believe we'll still have to pretend to be a winform control to allow the D3D render surfaces to punch through onto the screen
Hope this helps
PS - one side question - You capitalized Virtual Human -- you aren't referencing the NIH Visible Human Project, are you ? If so, last I knew you had to assemble the geometry/bones yourself , all it supplies is the tomagraphic slices