Christoph Hormann wrote:

>Sounds like you do not need a 3d-array for that, shouldn't it also work
>on a normal heightfield in a similar way, 

Yes/No, you can't make overhangs with a HF.
But more important, this is my first real attempt at programming something 
(besides the occasional modifying a pre-recorded-office-vba-macro). The 
DF3 format is simple but for HF's TGA's or PNG's have to be manipulated, 
not up to that yet.

>it would be similar to your
>method, but like with only two possible values (0, 1) for each voxel.

Sorry, I don't understand the "only two possible values ..." part.


Ingo

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ingo wrote:
> 
> 
> Yes/No, you can't make overhangs with a HF.
> But more important, this is my first real attempt at programming something
> (besides the occasional modifying a pre-recorded-office-vba-macro). The
> DF3 format is simple but for HF's TGA's or PNG's have to be manipulated,
> not up to that yet.

If i understood your description right, your code does not generate any
overhangs.

BTW, TGA format also seems quite simple to me.  

> 
> >it would be similar to your
> >method, but like with only two possible values (0, 1) for each voxel.
> 
> Sorry, I don't understand the "only two possible values ..." part.
> 
> Ingo
> 

Ok, that was just my own way of thinking.  I meant you can not decrease the
value of a voxel by 2 in a heightfield (because there are no voxels :-).  Forget
about it, i will try to work out some similar code for heightfields soon.

Christoph

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Christoph Hormann <chr### [at] gmxde>
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Christoph Hormann wrote:

>If i understood your description right, your code does not generate any
>overhangs.

By the randomly bouncing the drop around within one "layer" it should 
happen. I'll have to work on it a bit/lot more.

>BTW, TGA format also seems quite simple to me.  

I'll look into it.

Ingo

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In article <8F7FCD07Bseed7@204.213.191.228>, ing### [at] homenl (ingo) 
wrote:

> Generate a "raindrop" with a force between 0 and 10.
> Go to the first voxel in the first layer. If value of the voxel is 0, go 
> to the first voxel in the next layer (=z direction).
> Reduce voxel and raindrop by two. Is there still some juice in the drop, 
> randomly choose a direction +x, -x, +y or -y. Go in that direction till 
> you hit a voxel that is not 0. Reduce voxel and drop by two. Do so until 
> raindrop is 0 or you move outside the df3.
> Then generate a second drop, goto the second drop of the first layer etc. 
> Do so for all voxels in the layer. Then start all over again. Do this 20 
> times for each frame rendered.

Hmm, I wonder how hard it would be to make it follow the contours of the 
surface, and deposit material as well as removing it.

Another possible feature that should be a lot easier to implement: wind. 
Instead of going straight down to the first voxel, allow the direction 
to be skewed a little.

I can see other possibilities for variants of this algorithm: weathering 
on an ancient building or statue, etc.

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Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
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ingo wrote:
> 
> Christoph Hormann wrote:
> 
> >Sounds like you do not need a 3d-array for that, shouldn't it also work
> >on a normal heightfield in a similar way,
> 
> Yes/No, you can't make overhangs with a HF.
> But more important, this is my first real attempt at programming something
> (besides the occasional modifying a pre-recorded-office-vba-macro). The
> DF3 format is simple but for HF's TGA's or PNG's have to be manipulated,
> not up to that yet.

Since you did this in Python you can get Python Imaging Library from
here:
http://www.pythonware.com/products/pil/index.htm

It reads and writes PNG, JPG, BMP, it also read TGA, I think it's quite
a 
nice module, very simple to use... I'm not sure if the latest version is
available for windows, but there is one version for windows.

/Peter

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Peter Toneby wrote:

>Since you did this in Python you can get Python Imaging Library from
>here:
>http://www.pythonware.com/products/pil/index.htm

got it a minute ago, thanks.

Ingo

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Chris Huff wrote:

>Hmm, I wonder ......
>
>I can see other possibilities for variants of this algorithm: weathering 
>on an ancient building or statue, etc.
>

But first I try to get some speed in it :)

Ingo

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In article <8F805274Eseed7@204.213.191.228>, ing### [at] homenl (ingo) 
wrote:

> But first I try to get some speed in it :)

Rewrite it in C++. :-)

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Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
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Chris Huff wrote:

>Rewrite it in C++. :-)

... still learning how to crawl.

Ingo

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ingo wrote:
> 
> Chris Huff wrote:
> 
> >Rewrite it in C++. :-)
> 
> ... still learning how to crawl.
> 
> Ingo
> 

I could also suggest Delphi, then we have:

Python = crawling
Delphi = walking
C++ = dancing

<g,d&r>

Christoph

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Christoph Hormann <chr### [at] gmxde>
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