Redoing a scene I lost when my old PC went belly-up.

It's an idea I have for a painting that I want to make. So now I first  
want to try and create a "photo" to paint from - with Pov-Ray :)
I still need to add doors, windows, fire-escape and trash. Any suggestions  
on how to do these objects will be highly appreciated.

I ran into memory problems with the isosurface bricks, so this is a  
mixture of isosurface and mesh bricks using Bill Pragnells mesh relief  
macro. I have 5 different mesh bricks, randomly mirrored and rotated, but  
I still get 3 of the same bricks in a row. Any ideas on how to get it more  
random?

Also struggling with the tar texture. I'm trying to get the effect of old  
cracked tar. It's an isosurface using a pigment function.


Suggestions, help and critique welcome.

-Nekar Xenos-

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Attachments:
Download 'sunally.jpg' (318 KB)

Preview of image 'sunally.jpg'

"Nekar Xenos" <nek### [at] gmailcom> wrote:

> I have 5 different mesh bricks, randomly mirrored and rotated, but
> I still get 3 of the same bricks in a row. Any ideas on how to get it more
> random?

Ahh - I came across this problem several times in the past, and I ended up
learning about low-discrepancy sequences - which are completely non-random, but
more "randomly" distributed than a real random sequence.

My code for a halton sequence is:

#macro halton( index, base )
 #local out = 0.0;
 #local fraction = 1.0 / base;
 #local i = index;
 #while( i > 0 )
  #local remainder = mod( i, base );
  #local out = out + (fraction * remainder);
  #local i = int(i / base);
  #local fraction = fraction / base;
 #end

 out
#end

The base value is a prime number (the smaller the better), and the index can be
your brick number.

Get a value out of it with "halton( brick_number, 2 )".

> Suggestions, help and critique welcome.
>
> -Nekar Xenos-

Cheers,
Edouard.

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On Wed, 28 Apr 2010 07:33:29 +0200, Edouard <pov### [at] edouardinfo> wrote:


> Ahh - I came across this problem several times in the past, and I ended  
> up
> learning about low-discrepancy sequences - which are completely  
> non-random, but
> more "randomly" distributed than a real random sequence.
>
> My code for a halton sequence is:
>
> #macro halton( index, base )
>  #local out = 0.0;
>  #local fraction = 1.0 / base;
>  #local i = index;
>  #while( i > 0 )
>   #local remainder = mod( i, base );
>   #local out = out + (fraction * remainder);
>   #local i = int(i / base);
>   #local fraction = fraction / base;
>  #end
>
>  out
> #end
>
> The base value is a prime number (the smaller the better), and the index  
> can be
> your brick number.
>
> Get a value out of it with "halton( brick_number, 2 )".
>

> Cheers,
> Edouard.
>

Thanks!

-Nekar Xenos-

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"Nekar Xenos" <nek### [at] gmailcom> wrote:
> macro. I have 5 different mesh bricks, randomly mirrored and rotated, but
> I still get 3 of the same bricks in a row. Any ideas on how to get it more
> random?

Edouard already commented for the random selection - I was just going to suggest
varying the seed!

You could also very slightly perturb each brick's position and rotation (say, up
to 1% of a brick's width perpendicular to the wall, and up to half a degree on
the y). This can make the wall look more roughly put together. Another thing to
try is to vary the lightness of the bricks (doesn't need to be by much), so they
don't look like they all came from the same batch.

Love the sunflower and the washed-out sunlight!

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"Nekar Xenos" <nek### [at] gmailcom> wrote:
> I still get 3 of the same bricks in a row. Any ideas on how to get it more
> random?

Besides not having the same brick appear twice in a row, you probably don't want
the same brick appearing directly above or below. One possible method (although
not as cool as the previous suggestion) could be to create a two-dimensional
array (or three-dimensional, if you also want to worry about the corners of the
wall). Assign a number to each brick type, and store that number in the
corresponding array location as the bricks are placed in the wall. As you add a
new brick, compare the new brick type to the two bricks below and the one
already placed on the same row. If the new brick matches any of the already
created bricks, select a different type and compare again.

Regards,
Dave Blandston

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On Wed, 28 Apr 2010 10:24:53 +0200, Bill Pragnell
<bil### [at] hotmailcom> wrote:

> "Nekar Xenos" <nek### [at] gmailcom> wrote:
>> macro. I have 5 different mesh bricks, randomly mirrored and rotated,  
>> but
>> I still get 3 of the same bricks in a row. Any ideas on how to get it  
>> more
>> random?
>
> Edouard already commented for the random selection - I was just going to  
> suggest
> varying the seed!
>
> You could also very slightly perturb each brick's position and rotation  
> (say, up
> to 1% of a brick's width perpendicular to the wall, and up to half a  
> degree on
> the y). This can make the wall look more roughly put together. Another  
> thing to
> try is to vary the lightness of the bricks (doesn't need to be by much),  
> so they
> don't look like they all came from the same batch.
>
> Love the sunflower and the washed-out sunlight!
>
>

Thanks :)

-Nekar Xenos-

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On Wed, 28 Apr 2010 10:34:15 +0200, Dave Blandston <nomail@nomail> wrote:

> "Nekar Xenos" <nek### [at] gmailcom> wrote:
>> I still get 3 of the same bricks in a row. Any ideas on how to get it  
>> more
>> random?
>
> Besides not having the same brick appear twice in a row, you probably  
> don't want
> the same brick appearing directly above or below. One possible method  
> (although
> not as cool as the previous suggestion) could be to create a  
> two-dimensional
> array (or three-dimensional, if you also want to worry about the corners  
> of the
> wall). Assign a number to each brick type, and store that number in the
> corresponding array location as the bricks are placed in the wall. As  
> you add a
> new brick, compare the new brick type to the two bricks below and the one
> already placed on the same row. If the new brick matches any of the  
> already
> created bricks, select a different type and compare again.
>
> Regards,
> Dave Blandston
>
>

Hmm. There are 2 bricks above and 2 bricks below each brick and one on  
each side = 6 bricks. I'll have to make a larger variety of bricks!

-Nekar Xenos-

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"Nekar Xenos" <nek### [at] gmailcom> wrote:
> Hmm. There are 2 bricks above and 2 bricks below each brick and one on
> each side = 6 bricks. I'll have to make a larger variety of bricks!
>
> -Nekar Xenos-

Not necessarily. See the attached (plagerized) image. With three brick types,
it's possible that no brick would be directly adjacent to another brick of the
same type. There's not a whole lot of randomness in this case, though!

Regards,
Dave Blandston

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Attachments:
Download 'temp.jpg' (99 KB)

Preview of image 'temp.jpg'

"Nekar Xenos" <nek### [at] gmailcom> wrote:
> Hmm. There are 2 bricks above and 2 bricks below each brick and one on
> each side = 6 bricks. I'll have to make a larger variety of bricks!

I don't think you'll need very high-res meshes for this wall, so you should have
no problem with 10-20 different bricks in your array.

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On Wed, 28 Apr 2010 11:54:11 +0200, Dave Blandston <nomail@nomail> wrote:

> "Nekar Xenos" <nek### [at] gmailcom> wrote:
>> Hmm. There are 2 bricks above and 2 bricks below each brick and one on
>> each side = 6 bricks. I'll have to make a larger variety of bricks!
>>
>> -Nekar Xenos-
>
> Not necessarily. See the attached (plagerized) image. With three brick  
> types,
> it's possible that no brick would be directly adjacent to another brick  
> of the
> same type. There's not a whole lot of randomness in this case, though!
>
> Regards,
> Dave Blandston

Oh yes. I didn't think further... :)

-Nekar Xenos-

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