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Building a Water Splash

                         Building a Water Splash

Think of a ball dropping into a pool, and how a corona of water spurts out around it. The splash is vaguely symmetric, and is certainly not a group of primitive cylinders and tori merged together.

Building a splash like this using the Forms Editor is obscenely easy, much easier than the Coke can! It is even simple to animate the splash!

If we want to make a crude splash model, we should first envision what a cross section of such a splash would look like. The picture splash_one is a 10 second DPaint line drawing of how I see water would splash up and away at the peak of the splash. The center is disturbed but mostly flat, and there is a steep "wall" of water at at certain radius pointing out and up. It curls a bit at the top, with a bulge at the peak, and slopes back IN and down. Outside the wall the water is less disturbed. The wall is the 'shock wave' and is expanding (and falling) with time.

It is very, very easy to make a primitive version of this in the forms editor. We pretty obviously want our main axis that our slices are centered around to be vertical. Start a new form, with 30 points and 10 slices, which should give us enough detail to rough something out.

Initially, we'll want to make the splash symmetric. Later, we can add asymmetric details, but for now we want the coarse primitive to be radially symmetric, since it will define the basic structure of the form. Use the '90-degree' mode in the Symmetry menu.

The initial spherical horizontal cross section is completely useless for our purposes. Pick a height at which you want to base the splash (the bottom point of the cross section is a logical choice) and when you're building the splash, imagine that it is sitting on top of this water. It will give us a good reference point.

Pull the top point of the cross section way out and down to the water level. Keep the bottom point in at the center, and also at the water level. The inbetween points should be moved into a crude outline of the sloping water wall that we envisioned. My initial model is shown in the picture splash_two. It took about a minute to build.

Look at the perspective view. A bit bland, but it is certainly on the right track. Add a few points to the cross section at the top of the water wave to give it a more complex, bulging appearance. You might want to add some points near the base, especially on the inside, and make the water near the wave a bit more ragged.

Now what? Our coarse form was trivial to make, but is far to artificial. Let's jazz it up! Turn OFF symmetry, and muck around with ALL FOUR cross sections. You can increase the height of the wave in one, make the water a little rougher in another, make the peak on one a bit more curved... give them character. DON'T make huge changes like adding a second wave (you're welcome to try!) but certainly make them a bit different from each other. Think of adding a 25% noise level. You might keep an eye on the perspective view, as well- it will show you how the Forms Editor copes with blending these different shapes together.

Now what? A little more variation? There's no reason the splash has to be a perfect circle, or even an oval, is there? Of course not. The TOP display shows what the HORIZONTAL cross section of our splash looks like. Right now it's a nice circle. Now, our splash really should be pretty circular when looked from above, but not perfectly... Go ahead and muck with the shape, and again, watch the perspective view to see what happens. You might want to leave SOLID mode on, especially with a fast machine, since the wireframe of such a non-structured object is often very confusing.

You can move the radial points any way you like. I suggest that you only move them generally in and out, or the splash will get somewhat lopsided. Also, avoid having sharp spikes. You can see how easy it is to make our splash look like the Statue of Liberty's crown. 2 or 3 point bulges look very nice, major details formed with just 1 point are sharp and look like knives. Not very appropriate for a soft water splash!

My final splash is shown in the picture splash_three. A rendered version with three different splashes is called Ocean_Sunset. Ocean_Sunset is actually a still from the current version an anim I'm working on. It has the dolphins jumping around, the water moving with wind-driven waves, and eventually will have a ship slowly steaming along with a nice wake and smoke. The animation of the splashes still need a lot of tweeking, but it's getting better. This is still a work in progress, but it looks nice even now.

What about animation? I said it was easy to animate, but how? Well, let's think of what the animation SHOULD look like, then figure how to implement it. How does a splash evolve? The big wall of water starts at the center of the circle and moves outward at a pretty constant speed. It grows in height, curls over, and crashes down as is progresses. If we make maybe 4 or 5 splashes, one for each stage of the splashes growth, we can just move from one to the other. How? Morph! Morph is easy to forget when you're dealing with complex objects like splashes. Since morph requires its objects to have the same structure, different complex objects often won't work with each other. However, if we use the same basic starting form for each of the splashes (same # points and slices) we can have Imagine smoothly interpolate from one form to the next.

Considering the fact that creating the splash took maybe 5 minutes, you can see that making an entire animated splash is a 15 minute task. You don't even have to make new splashes, just modify old ones! When animated, you might add frills like separate objects for flying water droplets, and have them follow parabolic arcs. The Form Editor won't let you make detached objects like that, so you'll have to make them as separate objects that fly out, as opposed to pinch off and fly away... You might also use two different splash forms superimposed to give the splash a more complex character. The splash we built is still a bit plain.

This example should impress how easy it is to make complex shapes with an amazing amount of speed and control. Asteroid-maker, indeed!

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