Simulation - Animating with Blender: How to Create Short Animations from Start to Finish - page 247

(0.5 meters) than just the area of the glass. Also, due to the trial and error nature of creating a good simulation,
this particular setup took over 2 hours to get just right, let alone the 4 hours the fi nal solution took to compute
on a quad core system. Working with simulations is much like setting up a physical stunt or effect on a movie
set: You can set up the initial conditions, but it may take hours or days of tweaking and fooling around to get the
exact effect your are looking for.

That's not bad for something that will be central to a dramatic moment in an animation, and you have a
whole team of technicians devoted to tweaking and running the simulation at your disposal. However, that
means it probably won't be appropriate for anything less important. Also, the results, even at a relatively high
resolution, are less than stellar as you can see in the image.

In the case of the sink sprayer in The Beast , the domain turns out to be almost the entire area of the kitchen.
Domains are perfect cubes, so the shortest distance it could occupy is the line from the sprayer to the mom,
which is at least 3 feet. However, the water has to end up on the ground and splash up and away from her,
meaning that the domain must extend even further: from a foot above her head down to the fl oor. Now
the domain is over 2 meters square. To achieve enough detail just to see the fl uid coming out of the nozzle
requires a resolution setting of over 250. This will require 1.47 GB of RAM and starts to come back at over
a half-hour per frame during calculation. So even to see anything, let alone get a decent result, is already
beyond the capabilities of my systems.

It's surprising how quickly the feasibility of using a true simulation disappears.

So if you have a small controlled situation, or something on a larger scale where “anything goes” and the
detail does not have to be too high, the fl uid simulator can work well. However, if you're doing something
more ambitious, you will have to look elsewhere.

If you do choose to use a simulation, integrating it into your animation shot is not that diffi cult. It's best if
it is done directly within the shot fi le with all local objects, just to avoid any incompatibilities that might
be lurking between the fl uid simulator and linked
objects. Any animation that needs to interact with
the fl uids should be done before the simulation
so that the fl uid can react to the moving obstacle.
The fl uid simulator does not recognize deforma-
tion animation, so you will have to come up with
another solution if your character needs to splash
or otherwise affect the fl uid.

The best way to do this is to create a dummy object
or two and keyframe them to match the motion of
your character. In Figure 14.7, you can see the Beast
holding his hand under a fl uid simulation. As the
Beast moves his hand, the simulation reacts appro-
priately. To accomplish this, the Beast's arm mesh

Figure 14.7 The Beast splashing the water