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I'm trying to freshen up my heightfields to make them a bit more like
terrain. I've seen examples where various packages used erosion to make
more realistic terrain. I (obiously) know what erosion is, how it
works, but HOW THE HECK do you model it mathematicly???? I'm a bit lost
there [smile].
If anyone could provide some pseduo code with what it requires, it would
be greatly appcreciated. I'm am not looking for a POV example, as this
won't be written into POV, but into an external C program. I have also
tried looking at HF-Lab and can't figure out what makes its erosion
engine tick.
Yann
--
--------------------------------------------------------------------
Yann Ramin atr### [at] atrustrivalie euorg
Atrus Trivalie Productions www.redshift.com/~yramin
Monterey High IT www.montereyhigh.com
ICQ 46805627
AIM oddatrus
Marina, CA
IRM Developer Network Toaster Developer
SNTS Developer KLevel Developer
(yes, this .signature is way too big)
"All cats die. Socrates is dead. Therefore Socrates is a cat."
- The Logician
THE STORY OF CREATION
In the beginning there was data. The data was without form and null,
and darkness was upon the face of the console; and the Spirit of IBM
was moving over the face of the market. And DEC said, "Let there be
registers"; and there were registers. And DEC saw that they carried;
and DEC seperated the data from the instructions. DEC called the data
Stack, and the instructions they called Code. And there was evening
and there was a maorning, one interrupt...
-- Rico Tudor
William Safire's Rules for Writers:
Remembe
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Yann Ramin wrote:
> I'm trying to freshen up my heightfields to make them a bit more like
> terrain. I've seen examples where various packages used erosion to make
> more realistic terrain. I (obiously) know what erosion is, how it
> works, but HOW THE HECK do you model it mathematicly???? I'm a bit lost
> there [smile].
>
> If anyone could provide some pseduo code with what it requires, it would
> be greatly appcreciated. I'm am not looking for a POV example, as this
> won't be written into POV, but into an external C program. I have also
> tried looking at HF-Lab and can't figure out what makes its erosion
> engine tick.
There are some POV examples in these groups from a couple of weeks to a
month back but I can't remember which group/s.
I suppose you would follow the path of a water droplet falling
vertically/other from the sky and taking some soil with it - allowing for
deposition & erosion.
You might try e-mailing the author of HF-Lab & other HF programs that have
this feature to ask the algorithm.
--
Bye
Pabs
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Pabs wrote:
> You might try e-mailing the author of HF-Lab & other HF programs that have
> this feature to ask the algorithm.
I have talked with John Beale in the past and found him talkative and
willing to share info where possible.
--
Ken Tyler - 1400+ POV-Ray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/
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Yann Ramin wrote:
>
> I'm trying to freshen up my heightfields to make them a bit more like
> terrain. I've seen examples where various packages used erosion to make
> more realistic terrain. I (obiously) know what erosion is, how it
> works, but HOW THE HECK do you model it mathematicly???? I'm a bit lost
> there [smile].
>
> If anyone could provide some pseduo code with what it requires, it would
> be greatly appcreciated. I'm am not looking for a POV example, as this
> won't be written into POV, but into an external C program. I have also
> tried looking at HF-Lab and can't figure out what makes its erosion
> engine tick.
>
I never understood John Beale's code totally, but I think it calculates an
array, where the valuses are equivalent to the uphill area at this point, which
is related to the amount of water flowing there. Usually you are substracting
this array from your terrain.
All this calculates pure water erosion. To create realistic effects, it
requires much smoothing to simulate the flattening of the structures created by
the water over the time.
Maybe you want to check the samples i made for a fast thermal erosion code. One
I posted in p.b.i some time ago. Some more including a sort avi film are on my
pages:
http://www.schunter.etc.tu-bs.de/~chris/erosion1.html
Christoph
--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/
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Christoph Hormann wrote:
> Maybe you want to check the samples i made for a fast thermal erosion code. One
> I posted in p.b.i some time ago. Some more including a sort avi film are on my
> pages:
>
> http://www.schunter.etc.tu-bs.de/~chris/erosion1.html
Does your method simulate deposition of the eroded material?
-From the avi it does look like it does
--
Bye
Pabs
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Pabs wrote:
>
> Does your method simulate deposition of the eroded material?
> -From the avi it does look like it does
It's not a simulation of a physical move of material, it would never be that
fast then :-) I never checked how the volume of the terrain changes during the
process, but i think it stays quite constant in the avi.
Christoph
--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/
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Looked really neat, just seemed a lot more low area fill-in going on than
there was high-point sloughing resulting in a overall rise of the terrain.
But far as how it goes about it looked good top me. Maybe if it were
somehow excavated away in the lowest parts it might be better, as if it's
carried away, rather than stuck in the one region like a bowl formation
does. But I'm just expressing unknowledgeable opinion.
Bob
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Bob Hughes wrote:
>
> Looked really neat, just seemed a lot more low area fill-in going on than
> there was high-point sloughing resulting in a overall rise of the terrain.
> But far as how it goes about it looked good top me. Maybe if it were
> somehow excavated away in the lowest parts it might be better, as if it's
> carried away, rather than stuck in the one region like a bowl formation
> does. But I'm just expressing unknowledgeable opinion.
>
> Bob
I'm not sure whether i understood everything you wrote, but right now, the
overall height is always scaled to fit the whole range after each calculation.
As i already said it does not simulate physical processes, even though, you are
probably right, that there are some problems with nearly flat areas like the
bottom of basins. But i think it gets along with local minima much better than
John Beale's Water Erosion, even though you probably cannot compare it.
BTW, the in the avi, there is an additional high peak on the left not visible in
the camera, which affects the overall height of the terrain.
Christoph
--
Christoph Hormann <chr### [at] gmxde>
Homepage: http://www.schunter.etc.tu-bs.de/~chris/
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"Christoph Hormann" <Chr### [at] schunteretctu-bsde> wrote in
message news:397D49CF.4DFEE6C5@schunter.etc.tu-bs.de...
|
| BTW, the in the avi, there is an additional high peak on the left not
visible in
| the camera, which affects the overall height of the terrain.
Oh, I think that could explain the increasing height at the near corner
then. It just seemed to be expanding upward more than would be feasible for
being only the one major peak degrading. That's all I was talking about
before.
Actually, I like the narrowing channels at the lowest parts, even if there
doesn't appear to be any etching out of them. I think this is what was said
earlier, someone was trying to describe it too.
Bob
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I've always hated heightfields (read: never gotten good with them).
I think humanity would ultimately be served by someone figuring out an
algorithmic, mathematical way to "erode" a smooth rolling isosurface.
Yann Ramin wrote:
> I'm trying to freshen up my heightfields to make them a bit more like
> terrain. I've seen examples where various packages used erosion to make
> more realistic terrain. I (obiously) know what erosion is, how it
> works, but HOW THE HECK do you model it mathematicly???? I'm a bit lost
> there [smile].
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