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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
Post a reply to this message
Attachments:
Download 'vegetation wip1.jpg' (332 KB)
Preview of image 'vegetation wip1.jpg'
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Wow! That's amazing.
DLM
"Norbert Kern" <nor### [at] t-online de> wrote in message
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
>
Post a reply to this message
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Norbert Kern wrote:
> Hi,
>
> I want to share the first results of my planned plant distribution tool.
Very nice.
> 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.
I assume you use a union of discs and trace it. This is not really
linear but you probably reduced it to O(n*m) where only n is calculated
in interpreted code and m is in the builtin trace() (it could probably
actually be O(n*log(m)) but the bounding structures are not yet
generated at parse time AFAIK).
BTW if you generate cones/spheres instead of discs you could avoid the
additional pigment evaluation and determine the distance from the
vertical coordinate/normal.
A hardcoded implementation of this would still be way faster since you
could store the plants in a spatial data structure.
Christoph
--
POV-Ray tutorials, include files, Landscape of the week:
http://www.imagico.de/ (Last updated 01 Jun. 2006)
MegaPOV with mechanics simulation: http://megapov.inetart.net/
Post a reply to this message
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dlm spake:
> Wow! That's amazing.
> DLM
I agree!
Going to make it available soon? My mouth is already watering. It will look
very good in a scene I'm currently working on.
Nicely done,
--
Stefan Viljoen
Software Support Technician / Programmer
Polar Design Solutions
Post a reply to this message
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Christoph Hormann <chr### [at] gmxde> wrote:
> I assume you use a union of discs and trace it. This is not really
> linear..
Thank you for the hint! Now I know, why my render time rised with a power of
two whereas I assumed the contrary. But I've an idea to overcome this
challenge.
> A hardcoded implementation of this would still be way faster since you
> could store the plants in a spatial data structure.
What is a spatial data structure?
Norbert Kern
Post a reply to this message
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Thank you!
To publish the plant distribution tool will take time, because first I've to
solve some speed issues, then I need experience with my plant parameters and
finally I want to implement new features...
But if you want to use it as it is now I can send you the code.
Norbert Kern
Post a reply to this message
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"dlm" <me### [at] addressinvalid> wrote:
> Wow! That's amazing.
> DLM
Thank you very much!
Norbert Kern
Post a reply to this message
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news: web.44aecceb9373cf132680557b0@news.povray.org...
> Hi,
>
> I want to share the first results of my planned plant distribution tool.
>
Wonderfull!!
I think you used it for your IRTC Light and Fog entry and not for the Music
round.
Marc
Post a reply to this message
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I'm being told to get offline, so I haven't gotten more than a page into the
PDF, but I assume there is some way of determining how a plant is replaced?
Can it depend on elevation, or water concentration? That is, do I get to
make an image (or something) that would allow variations in the ecosystem,
have a higher plant density at a creek and lower on rocky ground, with
varaiation in the type of population in each area? It seems like it would
be too hard to give the replacement a type given a probability map for the
set of possible plants. I just going off the top of my head here, but this
is really, really cool - it's got me excited.
Thanks for showing it to us.
-s
5TF!
Post a reply to this message
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"M_a_r_c" <jac### [at] wanadoofr> wrote:
> Wonderfull!!
> I think you used it for your IRTC Light and Fog entry and not for the Music
> round.
Thank you, Marc!
In my 'Music' entry I used a single gradient pigment to control distribution
of grass, shrubs and trees. The flowers were meant to look like outpoured
notes from the violin. They were placed with the help of masks.
In my new entry for the 'Light and Fog' round I intended to use a plant
distribution tool in fact, but there was no time to accomplish it.
Now I want to demonstrate to myself, that I'm able to create such a tool.
There are good plant and tree generators and some have written excellent
landscape generators for povray. I hope to close the gap betwen them.
Norbert Kern
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