Bone Animation Concept in XNA

[brainydexter]

Aighh..I am trying to learn to make the animation stored in a model to work in xna. Now, I have been reading some stuff and I understand that XNA processes the animation data, but thats about it. Well, I read a couple of few things and I just want to make sure that what I understood is correct (so, this post can run long, and >> I warned you ).

Here it goes :
Syntax is in blue and the classname is in red
>> Root is the root (BoneContent type) of the given skeletan.
Root.Animations => (Animations is a property of type AnimationContentDictionary)

Animations: This property holds all the animations associated with a model(for e.g. walking, running, jumping) in AnimationContentDictionary.

AnimationContentDictionary : is a dictionary of <string name, AnimationContent>
where name = name of the animation and AnimationContent is the animation data for that animation of the whole model

Thus, one AnimationContent describes a single animation (for e.g. walking).

AnimationContent (e.g. WALK):
It contains a collection of data channels. Also, it represents one complete animation for the model; which can be visualized with all the data channels working together.
AnimationContent.Channels => (Channels is a property of type AnimationChannelDictionary)

AnimationChannelDictionary : Dictionary of <string name, AnimationChannel>
where name = name of the object being animated by each channel.

AnimationChannel (e.g. Movement of right leg in WALKing animation= 1 AnimationChannel):
It is a collection of Keyframes describing the movement of a single object/bone.
class AnimationChannel : ICollection<AnimationKeyframe>
Thus, I said AnimationChannel "is" made up of a bunch of AnimationKeyFrame.

AnimationKey:
It describes the position of AnimationChannel at a single point in time, a.k.a, the position of the associated bone/object (from the AnimationChannelDictionary.Key (string)).
It comprises of these members which completely describe the AnimationChannel:
Matrix Transform : Position/Orientation
TimeSpan Time: Time instant

I want to know if I understood these three things correctly or not? Is there something that I am missing here? Also, I will soon be posting about using animations in XNA and I will be using these classes to extract the animation info. Thus, I wanted to be crystal clear with them, before I proceed.

Also, this might sound like a dumb question, but What is the difference between meshes and bones ?

Thanks a lot

(My source has been mostly msdn)

[sbodie]

Here's a tutorial from the XNA website that in the least will be another resource for you to look through.

http://creators.xna.com/en-US/sample/simpleanimation

[brainydexter]

Thanks for the link

They take individual parts from a model, and animate it via transformations from code.

I am trying to write a generic library which would let u animate .x models. I have actually written the model processor, content reader/writer for it. But, need to write the last class which would bring it all together..anyways, ill keep posting here as i make progress.