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From: Tim Nikias v2 0
Subject: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 28 May 2003 20:51:04
Message: <3ed55978@news.povray.org>
Another try, now with a longer stream
and some "rocks" (as suggested by
Dave). Had some side-effects, which become
obious somewhat later in the animation.

All in all, it seems to be too much work for
flowing streams using this system. Would
probably be better to use a similiar approach
(node-based calculations for a mesh) and
generate some basic flow data and then
superimpose some random waves onto that
to get a similiar look.

I'll probably still release the little snippet of
code I wrote for this, just in case someone
wants the insight into this and wants to work
on it.

To be honest, I've never expected the algorithm
to be more useful than for non-moving, confined
water-surfaces, so I'm not that disappointed... :-)

Regards,
Tim

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde


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Attachments:
Download 'flowtest_lq.mpg' (275 KB)

From: Kitsune e
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 00:10:01
Message: <web.3ed58655281c5d5014d0b2c20@news.povray.org>
Tim Nikias v2.0 wrote:
>Another try, now with a longer stream
>and some "rocks" (as suggested by
>Dave). Had some side-effects, which become
>obious somewhat later in the animation.
>

Wow! the begining looks very convincing, I wonder why the waves are
multiplying as they go through.  Still this is a very clever use of your
system, I think if I wanted to use it in a scene though I would get the
data for one full rotation and then run it in a loop.

Can't wait to see the macros!


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From: Sir Charles W  Shults III
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 02:01:24
Message: <3ed5a234@news.povray.org>
Stunning!  If you get your energy to follow a log curve instead, it will
dampen and stay there instead of growing out of control.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip


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From: Tim Nikias v2 0
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 05:58:34
Message: <3ed5d9ca@news.povray.org>
I'll put them up on my website sometime this
day (once I get to it). Thanks for the comment!


-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde

> Tim Nikias v2.0 wrote:
> >Another try, now with a longer stream
> >and some "rocks" (as suggested by
> >Dave). Had some side-effects, which become
> >obious somewhat later in the animation.
> >
>
> Wow! the begining looks very convincing, I wonder why the waves are
> multiplying as they go through.  Still this is a very clever use of your
> system, I think if I wanted to use it in a scene though I would get the
> data for one full rotation and then run it in a loop.
>
> Can't wait to see the macros!
>
>


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From: Tim Nikias v2 0
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 05:59:19
Message: <3ed5d9f7@news.povray.org>
I'm not sure what you're after with "energy" and
"log curve"... Care to explain?

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde

>     Stunning!  If you get your energy to follow a log curve instead, it
will
> dampen and stay there instead of growing out of control.
>
> Cheers!
>
> Chip Shults
> My robotics, space and CGI web page - http://home.cfl.rr.com/aichip
>
>


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From: Peter Popov
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 08:25:38
Message: <c1vbdv0qpjq0h9fotglunnuigl79j9psp5@4ax.com>
Behold! Ulmo is rising!


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] vipbg
TAG      e-mail : pet### [at] tagpovrayorg


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From: Sir Charles W  Shults III
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 09:56:40
Message: <3ed61198@news.povray.org>
I haven't seen the code you use to produce the waves, but wave height is
equivalent to energy.  And since the waves continue to grow behind obstacles
rather unrealistically, it means that your "bookkeeping" of the height has an
error somewhere.  Real waves become broader rather than taller, and in some
cases they will spray droplets.
    My thought is that if there is too much involved in getting the energy math
right, it may be easier to use logarithms for the height rather than completely
redoing it all, and then the peaks will be severely curtailed instead of growing
so large.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip


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From: Tim Nikias v2 0
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 12:42:45
Message: <3ed63885$1@news.povray.org>
:-)
So, are you another one of those
LOTR-Fans?

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde

> Behold! Ulmo is rising!
>
>
> Peter Popov ICQ : 15002700
> Personal e-mail : pet### [at] vipbg
> TAG      e-mail : pet### [at] tagpovrayorg


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From: Tim Nikias v2 0
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 12:45:13
Message: <3ed63919@news.povray.org>
The algorithm I use is pretty simple: I store
the heights, smoothen these outward onto neighbouring
nodes. To save parsing time, I leave out nodes which
are inside objects, which seems to produce the
error in this case: since the blocked nodes aren't
processed correctly (and thus aren't set to 0), they
add up and spill over later. Need to check more thoroughly
on that.
If you want, you can have a look at the source-code,
just head on to my homepage, in the downloads-
section.

Regards,
Tim

-- 
Tim Nikias v2.0
Homepage: http://www.digitaltwilight.de/no_lights
Email: Tim### [at] gmxde

>     I haven't seen the code you use to produce the waves, but wave height
is
> equivalent to energy.  And since the waves continue to grow behind
obstacles
> rather unrealistically, it means that your "bookkeeping" of the height has
an
> error somewhere.  Real waves become broader rather than taller, and in
some
> cases they will spray droplets.
>     My thought is that if there is too much involved in getting the energy
math
> right, it may be easier to use logarithms for the height rather than
completely
> redoing it all, and then the peaks will be severely curtailed instead of
growing
> so large.
>
> Cheers!
>
> Chip Shults
> My robotics, space and CGI web page - http://home.cfl.rr.com/aichip
>
>


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From: Hugo Asm
Subject: Re: 2nd Attempt at Flowing Water... (MPG, 274kb)
Date: 29 May 2003 13:05:14
Message: <3ed63dca$1@news.povray.org>
Great work, Tim! This may be a misuse of your macros, but it seems like it
could work.

> Would probably be better to use a similiar approach
> (node-based calculations for a mesh) and generate some
> basic flow data and then superimpose some random waves
> onto that to get a similiar look.

Interesting comment. Where can I read about this? I only have a vague
understanding. I think it's possible to precalculate data (one normal vector
for each node) with reference for the wave direction. This means, there will
be an overall direction (the wind) for the waves, and there will be a
sublayer where the waves go in all the directions that is specified by the
precalculated data... But how to push these subwaves around, within a
reasonable time, I don't know...?

Best regards,
Hugo


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