(reference image posted in images.binaries under title Blue Liquid II)

That got me thinking.
Water in my experience seems to be made of more concave surfaces than
positive curved ones.  The blob surfaces that I have built, and they are
many, tend toward convex. Flowing blobs look like mercury. I have put a lot
of work in to build flat and concave ones, but there is usually an easier
way.

Looking at the flowing water image it struck me that there was an easier
logic in what was happening above the liquid than in the liquid itself.  For
example to model the liquid clinging to the wall with blobs would be nasty,
stacked up in a pyramid configuration, sliding off the wall, surface tension
pulling the border back.  But if the negative space was modeled then only
one element would give the same curve against the wall, a sphere, or a
collection of sphere's blobbed together.

So giving it a shot, the image is a first attempt to recreate the Arete
animation.  The base element is a box, differenced with a blob, consisting
randomly placed, randomly sized and randomly strengthed spherical elements,
the "pour" is a cylindrical blob element that is negative to the other
positive blob elements.   The whole thing is given a media content and
rendered.  No animation steps, rendering time is five hours on a pentium II
400.

Now, since the direction is to model the space above the blob, I have in my
head a mental image of a box filled with ping pong balls, into which is
poured a stream of large ball bearings.  The "ping pong balls" are the blob
elements they form essentially a solid of the top of the "liquid".  For the
sake of this first concept the "ball bearings", are not rendered, they serve
to displace the larger and convex "ping pong balls", or air molecules, only
the lower surface of the blob "cloud" is rendered, as it boolean's the box.

I had seen this approach somewhere and it took racking my brain to remember,
there is a small shareware program that does beautiful animations of
particles and I highly recommend downloading it and playing with it, it will
open your eyes.   The program is called "Really" and it is written by
Giovanni Tummarelli in Italy, the program is a little bit rough in places,
but it lets one design arrangements of "atoms" and their character and let
them go at each other the objects collide and shiver and break apart in real
time, nothing short of amazing.    Load the "World" called Diver2 and watch,
think of the application of this in a Povray animation with blobs. It is all
of 450K big, and here is the URL;
http://www.ascu.unian.it/~tummarel/really.shtml  (considering the trouble I
had to go through to find it again, I would humbly nominate it for inclusion
in Ken's wondrous page of links, if only to make it easier to find the next
time.)

So, in conclusion, to render the water, it may be simple to render the
invisible air.

Shaw

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