Hey their, Nathan here.
I apologize if this is a common question , I have yet to see someone asking for help with game animations.

I am using Unity3D to build a 3rd Person open world survival adventure game.

I am struggling to see how animations are "Sewn" together, and I actually rather really respect animators is a funny sort away.
I'm just looking for some answers really.

I have a rather primitive walk animation cycle, and a idling cycle for my character , but I would like more details with more miscellaneous animations.
I'm currently looking at having a wolf attack the character as an enemy , and I want the character to wrestle with the wolf... how would this be done? how would I animate this inside 3dsMax or unity? how would the animations blend? would I animate the character and the wolf separately?

I have been also thinking about having huge trolls that would knock over trees in the game, also for the ability for the character to climb trees...
Am I getting over my head with this? - the only thing I can think of is using an ik engine for the climbing trees part. I don't know how devs do it in Uncharted , Tombraider or Assassins Creed (that is procedural animations.)
I just have a vision of a really awesome game - the best game - and I want to play it disparately , despite it doesn't exist yet
Please tell me other people get this feeling too?(want to play awesome games you made up that don't exist yet.)

Thanks for your time.

Nathan.

how would the animations blend? would I animate the character and the wolf separately?

You would have to line up the animation sequences through your scripting/coding of the game.
Yes, if they're used as separate animated objects, they'll run "attack human" and "be attacked by wolf" animations respectively.

Am I getting over my head with this?

That entirely depends on your skill level and experience.

As for animation blending, there are as many solutions to that as there are games out there, but it usually involves interpolating bone transformations between two animation frames (i.e. manipulate this bone 75% by the "walk" cycle and 25% by the "kick the ogre" animation when I'm 25% of the way through the transition from walking to ogre-kicking). Also, scenegraphs help process bone chains so the translation of the body's root bone (based on player movement) is already applied to any animations that may be happening on a child bone (like a gun firing, sword swinging, or facial expressions) while the character is running.