im still having problems understanding isosurfaces.

how would a function look like that creates a hole through a box?

let me explain in 2D from top down:

#########
#########
#########
###   ###
###   ###
###   ###
#########
#########
#########

thanks!

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Wasn't it ehmdjii who wrote:
>im still having problems understanding isosurfaces.
>
>how would a function look like that creates a hole through a box?
>
>let me explain in 2D from top down:
>
>#########
>#########
>#########
>###   ###
>###   ###
>###   ###
>#########
>#########
>#########
>
>thanks!

In my isosurface tutorial you can find out how to make an isosurface box
here: http://www.econym.demon.co.uk/isotut/simple.htm#box

and how to create the intersection of two isosurfaces here:
http://www.econym.demon.co.uk/isotut/combine.htm#inters

But you want the difference, not the intersection, so you need to turn
the inner isosurface inside out:
http://www.econym.demon.co.uk/isotut/insideout.htm

-- 
Mike Williams
Gentleman of Leisure

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On Wed, 3 Dec 2003 06:07:16 +0000, Mike Williams
<nos### [at] econymdemoncouk> wrote:

>In my isosurface tutorial you can find out how to make an isosurface box
>here: http://www.econym.demon.co.uk/isotut/simple.htm#box

hi Mike!
Your tutorial is great!
Is there a downloadable and printable version.
I love to learn such things in bed...;-)
-- 
Erhard Ducke

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Wasn't it Erhard Ducke who wrote:
>On Wed, 3 Dec 2003 06:07:16 +0000, Mike Williams
><nos### [at] econymdemoncouk> wrote:
>
>>In my isosurface tutorial you can find out how to make an isosurface box
>>here: http://www.econym.demon.co.uk/isotut/simple.htm#box
>
>hi Mike!
>Your tutorial is great!
>Is there a downloadable and printable version.
>I love to learn such things in bed...;-)

There's only what you see there, the web pages and the zips of the
example files. The only way to download it is to use File->SaveAs in
your browser. To print them I suggest trying switching off "Print
background colours and images" and either setting your View text size to
"smallest" or telling your browser to print in landscape mode. 

I've not actually checked whether all the pages print correctly with
those settings, and it might depend on what printer you use. [The
problem is that I use <pre> to control the formatting of samples of
code, and that can prevent the browser reformatting the page to be
narrow enough to fit.]

-- 
Mike Williams
Gentleman of Leisure

Post a reply to this message

> Wasn't it Erhard Ducke who wrote:
>>Your tutorial is great!
>>Is there a downloadable and printable version.

> And Mike Williams replied:
> There's only what you see there, the web pages and the zips of the
> example files. The only way to download it is to use File->SaveAs in
> your browser. To print them I suggest trying switching off "Print
> background colours and images" and either setting your View text size to
> "smallest" or telling your browser to print in landscape mode. 
> 
> I've not actually checked whether all the pages print correctly with
> those settings, and it might depend on what printer you use. [The
> problem is that I use <pre> to control the formatting of samples of
> code, and that can prevent the browser reformatting the page to be
> narrow enough to fit.]

One of the best features of Adobe Acrobat is the ability to create pdf documents 
from web URLs, including multiple pages with links. Your Isosurface tutorial 
became a 106 page pdf that I can read at home (where I have a 16.6K (max) 
dial-up connection).

Just a note: the links to the three moebius images on the param.inc page are broken.

Thanks for the tutorial. I refer to it quite a bit. You did an excellent job.

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Mike Williams <nos### [at] econymdemoncouk> wrote in news:2QZuLHAU2Xz
$Ewr### [at] econymdemoncouk:

> But you want the difference, not the intersection, so you need to turn
> the inner isosurface inside out:
> http://www.econym.demon.co.uk/isotut/insideout.htm

your tutorial is great! thanks!
i found a method to do it, but a little bit different:

#declare X=function{x}
#declare Y=function{y}                  
         
isosurface {
    function { min(X(x,y,z),Y(x,y,z),-X(x,y,z),-Y(x,y,z)) }  
    threshold -0.5
    contained_by { box { -1, 1 } }
} 

thanks!

btw: i saw, that you are also into fractals.
have you ever made an isosurfacefunction that generates a fractal 
landscape with midpoint displacement algorithm?
(maybe i should open a new thread for this)

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On Wed, 03 Dec 2003 15:17:40 -0700, Tim Riley <tim### [at] netscapenet>
wrote:

>One of the best features of Adobe Acrobat is the ability to create pdf documents 
>from web URLs, including multiple pages with links. Your Isosurface tutorial 
>became a 106 page pdf that I can read at home (where I have a 16.6K (max) 
>dial-up connection).

Can I download it anywhere?
Thanks in advance!
And many thanks to Mike for this great tutorial!
-- 
Erhard Ducke

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Erhard Ducke wrote:
> Can I download it anywhere?
> Thanks in advance!
> And many thanks to Mike for this great tutorial!

I don't maintain a webspace, but I could email it (it's ~1.9MB) but I suppose I 
should ask Mike's permission first.

Post a reply to this message

Wasn't it Tim Riley who wrote:
>Erhard Ducke wrote:
>> Can I download it anywhere?
>> Thanks in advance!
>> And many thanks to Mike for this great tutorial!
>
>I don't maintain a webspace, but I could email it (it's ~1.9MB) but I suppose I 
>should ask Mike's permission first.

Permission granted.

-- 
Mike Williams
Gentleman of Leisure

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On Sat, 6 Dec 2003 03:32:22 +0000, Mike Williams
<nos### [at] econymdemoncouk> wrote:

>Permission granted.

Thanks! :-)
Perhaps you can upload it to your website?!
-- 
Erhard Ducke

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