I've started looking at all the animation stuff even got my Havok tools installed but most of the tutorials talk about using skeleton.hkx but what is it? I'm hoping someone can give me a little understanding of what each type of .hkx file is for, like ####project.hkx, ####behaviour.hkx, ###character.hkx etc. I'd like to have a bit of an understanding of what these are and ment to do before I start playing with them.

Use hkxcmd to convert it to xml if you want to have a look. It contains data about the skeleton such as the names of the bones and some stuff about the ragdoll skeleton, bone transforms, etc. You don't really need to know much about it other than the bone names and indices perhaps. It depends on what you want to do.

As for the others, ####project.hkx references ###character.hkx. ###character.hkx contains a list of all the character's animations (you need to add any new animations to the bottom of this list), it contains information about foot inverse kinematics, it contains bone weight arrays (used for animation blending) and references the character's skeleton and root behavior file.

It's just that this Dalek is custom skin mesh with a custom skeleton.nif which I built so there isn't any .hkx files to start with, I have to build it all from scratch.

Edit...

Could I think of these files as an animation / havok version of the physical nif files?