Firstly, each shot is a long continuous action sequence lasting 15 to 20 second seach, with full 3D camera movement and framing to accentuate different parts of the action. I have 50 seconds done, in 4 shots, which kind of gives you the idea. Having a moving camera (vs a stationary cam and creating camera movement in post) accentuates the action but adds up in rendering time.
What is more labor intensive, however, is the multiple layers of effects, which can weigh in at 70 to 100 layers per shot, with nested comps, z depth maps to get everything where it should go, etc. A typical dialog shot would only have the background, the actors and maybe a background environmental effect (clouds /rain / etc) and be 6 to 8 layers max.
This is all to make the action sequence stand out on it's own, as well as accentuate the rest of the film and place it in a context of a wider conflict that is raging around the main storyline.
Within another couple of weeks I should reach the critical mass of at least 2 mins of this battle sequence, which then transitions back into the climax of the film (which is, again, another exciting and labor intensive action packed sequence)
I may be at this for a while...
* ARC, another little acronym I've made up that means Animate Render Comp. This has nothing to do with my title ARChon defender, aside from a nerdly humorous coincidence... ...significant only to myself, I suppose ;D