>
> Thank you!
> In fact such a tool is always a fake. I try not to confuse it with reality -
> it only has to simulate it. This is because of the control paramenters which
> I cannot adjust in a correct way simply because I don't know them. By
> example, what is the optimum soil humidity for nettles? At least nettles
> seem to grow everywhere, so they can tolerate many conditions from sunny to
> pure shady locations. Perhaps they tolerate conditions other plants simply
> don't like, but aren't good in competing with other species. In this
> respect my model won't be very different from a pure guess.
>
> For water availability I got a tip of Prof. Deussen, one of the Xfrog
> authors.
> The function, which defines the ground can also serve as approximation to
> water content.
>
> Rocks are easy - they cast shadows. A simple image which defines shadowing
> from rocks, big plants, houses and so on is sufficient to define smaller
> and less dense vegetation near rocks. Near trees you have to consider the
> roots too, which lower water availability at those points.
>
> Probability maps are nice. In fact I used simple examples for some of my
> images. But with a little practice you can see the difference to an
> iterative approach.
>
>
> Norbert Kern

Yes, I understand/see the iterative process makes a major difference - what
I am wondering is if the method you are using takes into account both the
terrain and the neigboring plants, or just the latter. Anyway, now I have
time so I'll just hunker down and read the PDF.

As far as the reality of the control paramenters -- It doesn't really amtter
if they are the real numbers, does it? The look of the thing is in the
variation itself. You could use entirely fictional plants, and the process
would still give you a result that is pleasing to the eye, because it
defies the regularity of a less intensive approach. If you wanted it to be
*just* like the real world, well, I have a very nice camera you could
borrow ;) Seriously, though, it looks fantastic.

-s
5TF!

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"stm31415" <sam### [at] cscom> wrote:

> Yes, I understand/see the iterative process makes a major difference - what
> I am wondering is if the method you are using takes into account both the
> terrain and the neigboring plants, or just the latter.


Only plant competition was considered in WIP 1.
In the mean time I integrated water availability.


> As far as the reality of the control paramenters -- It doesn't really amtter
> if they are the real numbers, does it? The look of the thing is in the
> variation itself. You could use entirely fictional plants, and the process
> would still give you a result that is pleasing to the eye, because it
> defies the regularity of a less intensive approach. If you wanted it to be
> *just* like the real world, well, I have a very nice camera you could
> borrow ;) Seriously, though, it looks fantastic.


Thank you again. I fully agree with you.


Norbert Kern

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Not sure I understand exactly how it works but the outcome looks great..

Sean

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"Norbert Kern" <nor### [at] t-onlinede> wrote:
> Hi,
>
> I want to share the first results of my planned plant distribution tool.
>
> In principle it's an solvable problem, see
> http://graphics.stanford.edu/papers/ecosys/ecosys.pdf for a basic procedure
> example.
> First you have to check distances to all neighbors of each plant. Dependent
> of the distance and whether the neighbor is another species or not,
> increase or decrease the size of the plants. A plant will be replaced after
> several iterations or if the size becomes too small.
> The problem is to avoid checking each plant against each other on each
> iteration, because this leads to n*(n-1) checks, if n is the number of
> plants.

Wow, sounds like a neat project.  I have tp try to avoid things like that
these days, otherwise everything else I have to do suffers.  If you want to
do some more technical work on the n*(n-1) problem, have a look at this
recent thread on the random placment of non-intersecting spheres
(http://news.povray.org/povray.advanced-users/thread/%3C446b33a3@news.povray.org%3E/).
 Especially the code I put together which sets up a proximity search and
speeds things up enormously.  Good luck, and I can't wait to see more of
this in action.
-tgq

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"Trevor G Quayle" <Tin### [at] hotmailcom> wrote:

> Wow, sounds like a neat project.  I have to try to avoid things like that
> these days, otherwise everything else I have to do suffers.  If you want to
> do some more technical work on the n*(n-1) problem, have a look at this
> recent thread on the random placment of non-intersecting spheres
>
(http://news.povray.org/povray.advanced-users/thread/%3C446b33a3@news.povray.org%3E/).
>  Especially the code I put together which sets up a proximity search and
> speeds things up enormously.  Good luck, and I can't wait to see more of
> this in action.


Thank you for the tip - it will take time to understand the details.

Norbert Kern

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"s.day" <s.d### [at] uelacuk> wrote:
> Not sure I understand exactly how it works but the outcome looks great..
>
> Sean

Thank you, Sean.
It's a pity not to see an IRTC entry from you last round.


Norbert Kern

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that's fantastic. by far one of the most interesting posts here in a while.

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"Ross" <rli### [at] everestkcnet> wrote:
> that's fantastic. by far one of the most interesting posts here in a while.



Thank you very much! That's encouraging.


Norbert Kern

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"Norbert Kern" <nor### [at] t-onlinede> wrote:
>
> Thank you, Sean.
> It's a pity not to see an IRTC entry from you last round.
>

Thanks Norbert, I did not have any good ideas for the last round or much
time to experiment but I have already started on my entry for this round..
I hope to see another scene from you, your last two entries have been
excellent!

Sean

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This tool of yours, can it be downloaded somewhere? I would love to try it 
out...

Sven



"Norbert Kern" <nor### [at] t-onlinede> schrieb im Newsbeitrag 
news:web.44aecceb9373cf132680557b0@news.povray.org...
> Hi,
>
> I want to share the first results of my planned plant distribution tool.
>
> In principle it's an solvable problem, see
> http://graphics.stanford.edu/papers/ecosys/ecosys.pdf for a basic 
> procedure
> example.
> First you have to check distances to all neighbors of each plant. 
> Dependent
> of the distance and whether the neighbor is another species or not,
> increase or decrease the size of the plants. A plant will be replaced 
> after
> several iterations or if the size becomes too small.
> The problem is to avoid checking each plant against each other on each
> iteration, because this leads to n*(n-1) checks, if n is the number of
> plants.
>
> My idea is to use my favorite povray commands - 'trace' and 
> 'eval_pigment'.
> For each plant a disc is defined with a cylindrical pigment. Then you 
> search
> for neighbors by conducting traces. If you hit a neighboring disc, you 
> check
> the pigment at this point. This way I 'linearized' the problem, at least I
> hope so.
> So I implemented aging and influences of several species - light, water,
> roots, (soils, slope...) will be considered next.
>
> The image shows distributions of four species after 1, 10 and 40 
> iterations,
> each with equal plant parameters. A regular start distribution pattern was
> chosen to show the effect. After 40 iterations representing 2.5 average
> lifetimes no pattern is recognizable anymore.
> A simple render with four different plants shows this result.
>
>
> Norbert Kern
>

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