Liquid flying or falling through the air can take many forms. In this lesson we're studying liquid that's rising and falling, either with a controlled flow, such as water from a hose, or an uncontrolled flow, such as a waterfall or pouring from a bucket. We'll also look at various fountain types, from sheet sprays to a "bubbler" drinking fountain.
As we've studied liquid basics in previous lessons, this one has more emphasis on video lectures and practical exercises, than text and diagrams.
As we saw in the splash and surface tension lessons, when water free falls through the air we design and animate the effects of surface tension and gravity. In the case of a fountain, the way liquid behaves in the air initially depends on the aperture from which it emerges. In the video below we see a tube of water emerging from a simple round hole.
Regardless of the aperture shape, liquid conforms to the rules of surface tension and gravity. This means that while it may appear unique as it leaves the aperture, the longer it's airborne, the longer it has to form the old familiar liquid shapes of strings and beads.
Depending on the type of fountain in your scene, the water will behave accordingly. If water is being shot into the air, there'll be the initial upward direction, then the arc as gravity takes over. If it's simply falling from a hose or pipe, the water pressure and momentum will determine the arc, if any. Let's look at two common types of water design.
The video below shows some slow motion water from a hose. The nozzle is causing the water to spread as it leaves the hose, so we get to see sheets, strings and beads as they develop. You can pause this video on any frame for real inspiration on water design through each stage.
video fount_hose_sloMo
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video fount_airborneLiquid1
Exercise
With 2 or more drawings, design a water jet from a fire hose nozzle that arcs upward, through the air for approx 5-10 yards before it falls to the ground as a cloudy mist.
video fount_stringStrobe
Exercise
With 4-5 drawings, design a scene in which a column of liquid is gradually turned off.
When stylising the design of water or any other liquid, you can still make it appear realistic by drawing on what you know of real-world rules and physics. In the video below, the ninja's blood spurts out in wriggling "ropes" but the way it behaves and breaks up makes it somewhat believable as liquid.
When we animate water, we're not only animating the liquid itself but the effects of gravity acting on it. This means any arcs must be followed through as well as the wobbling of surface tension at work on the sheets, strings and beads.
In the case of the earlier example where water flow is gradually being cut off, there's no arc. The column of water is gradually thinned by surface tension, before breaking up into strobing beads. As I mentioned in the design video for this behaviour, I love to use this design in any scene where running water is being turned off, or running out.
Fig. 1 - From "Prowlies at the River". Running strings, followed by strobing beads.
In the video below, I'm animating a simple water bubbler, or drinking fountain. This is an interesting exercise because it combines rising water and falling water into what is mostly a singular volume.
video fount_drinkingFountain1
As you can see in the live action reference below, there's some really amazing and inspiring stuff going on in this effect. My animation above is very simple by comparison, but it just goes to show that there's a lot of room for experiments and variation.
The finished bubbler scene below shows one possible treatment for this effect.
video fount_bubblerTreatment
While this has been a short lesson, there is a world of practical liquid animation waiting for you. This lesson has touched on just a few types of airborne water and fountain styles, but keep your eye sharpened for real world examples of airborne water styles and designs. The methods and designs demonstrated here are useful not only for scenic or ambient environment effects like waterfalls or emptying buckets of water, but also less conventional and fun stuff, like gushing blood, vomit or pee!
