So far there have been many types of liquid animation scattered throughout this course; ripples, reflections, splashes and caustics to name a handful. This time we're looking at how water laps at a shallow shoreline, like on a beach. We won't concern ourselves just yet with the complexity of tumbling waves. We're looking first at how water moves and behaves on the shore, which as you'll later learn is the driving force behind wave breaks. You'll also revisit the foam concepts we talked about in the last lesson because they are a key aspect of this lesson's designs.
The type of shoreline we're animating is usually seen at the seaside, but if you've been on the bank of a river as a boat goes by - or god forbid, a jet ski (those things are awful noisy) you can see similar shoreline behaviour. The main feature of our shoreline in this article is the foam, so for the purpose of these exercises, we'll be animating the low foamy surge and retreat of a sea shore.
Above video: beach shoreline reference, via YouTube
We all know that water runs downhill which is why waves, when thrown onto a beach, always run back to the sea. This rhythmic rise and fall of the water's edge lends itself well to cyclic animation, but can be a very complex design task to avoid cheapness.
The simple part of this task is the waterline, which is essentially just a single line representing the very edge of the water. The difficult part is also the bit that's most important; the surface effects on the water. Even more difficult is making this animate well. Let's take a look at the design first.
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As I mentioned in the design section above, the thing that makes this effect so difficult to animate is the foamy water texture on the surface. There are easy ways to handle it but as in most cases, simplifying the process usually means simplifying the look of it. Let's look at those options before we move on to the more frame-by-frame methods.
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A commonly added treatment in scenes like this is a wet imprint left by the water on the sand. This is a very simple effect to achieve with a kind of residual silhouette of the water that fades after a second or two. It illustrates the water behind left behind and soaking rapidly into the wet sand.
Apart from the obligatory reflections, shadows and highlights, other types of treatment you might like to consider include are a fading and disintegration of the foam colour/texture and water colour. When a wave comes in and rolls up onto the beach, it's opaque with turbulent sand clouds that quickly settle, leaving the water clear as it falls back into the ocean. This change of opacity is easy to reproduce and can be enhanced with any refraction effects that your software is capable of.
The foam effect has been just one aspect of shoreline animation. The water line animation on its own can be customised and applied to a lapping shore whether sea, lake, river or pond. In a way then, it's the waterline lapping animation and timing that is a more important and versatile skill, whereas the foam texture is a very specific skill.
