But the whole water thing isn't just particle effects is it? There's the water mesh, the big thing with the streaming water texture. Wouldn't the particle effects be the little splurts of water against the rocks and all that?
You can animate water meshes the same way as you can a person/animal. Havok Behavior does not discriminate. I would assume that these rivers are a combination of mesh animations (unless the vertices on the water mesh are *completely* unchanging... blech!) and particle effects, as you can see water breaking around rocks and shores. There are also mist clouds. If they've already said they are using Havok Behavior to animate the effects in-game, and this obviously includes the rapids to some extent. I can't tell you if they animate the actual texture via some proprietary means, or if they use Havok Behavior as well.
What this means is that replacing this effect (other than the base water texture) could be hard or impossible, which was my original point and what I was replying to, if you trace my replies all the way back to the source. No matter how they do the rapids animation specifically, it doesn't change my original point, and it doesn't mean what I said about Havok Behavior is wrong as you claimed. They've already shared that they're using it for the particle effects, and a lot of the water is a particle effect. The waterfalls, the mist, the water breaking, even the streams in the cave are an effect. They're an "effect" because they're obviously not simulating real water when you see these things, and they have to be animated in advance, so I would assume they're using their new animation tool which they've already stated they're using for character animation and effects.
I would also assume they're using it for facial animation. Havok Behavior certainly supports animation blending and morph targeting... They could more or less have created all the "sounds" your face makes (the shape it makes, called a
viseme), and then in their dialog files have the face blend between all these sounds (called phonemes). And since they've stated that characters can now move about while speaking to you, this is very obviously the case... As they can let Havok behavior mix the cooking animation with the facial animation, or any other animation they wanted to. And then of course they would combine that with some Inverse Kinematics, like making sure the NPC is looking at you, and lining up its hands with the objects it should be manipulating.