On Fri, 5 Oct 2001 03:14:04 +0200, Lutz-Peter Hooge <lpv### [at] gmxde>
wrote:

>In article <3bbce60b.1409922@localhost>, PeterC@nym.alias.net.almost 
>says...
>
>> 	Been playing with isosurfaces in 3.5 and I am wondering
>> if the attached image is a bug or not. 
>
>This is a typical problem resulting from an insufficient max_gradient.
>Not a bug.
>
>Lutz-Peter

Thanks for the help.  Since I've never used Mega-POV, this whole
isosurface thing is completely new to me.

Pete

Post a reply to this message

On Fri, 05 Oct 2001 08:24:15 +0200, Christoph Hormann
<chr### [at] gmxde> wrote:

--snippage--

>
>Sorry, but sometimes i wonder why we put much work into the documentation
>if it's not read.  
>

Rather than playing dump-on-the-newbie as well as Oh-So-High-And
-Mighty, you *could* have referred me to the relevent section of the
documentation that I glaringly overlooked.

In other words, you expended the effort to reply to my posting
but contributed nothing.

Fortunately, others on these newsgroups with a less negative
frame of mind have posted helpful and informative posts.

Good day

Post a reply to this message

nospam wrote:
> 
> Rather than playing dump-on-the-newbie as well as Oh-So-High-And
> -Mighty, you *could* have referred me to the relevent section of the
> documentation that I glaringly overlooked.
> 
> In other words, you expended the effort to reply to my posting
> but contributed nothing.
> 

Sad you see it that way, looking for 'isosurface' in the help index will
bring you immediately it the relevant sections (isosurface
object/tutorial) and there you will find both the information needed to
solve the problem and the hints to understand it.

> Fortunately, others on these newsgroups with a less negative
> frame of mind have posted helpful and informative posts.
> 

I do not like this attitude.  If you don't appreciate the way i answered
your question that's ok, but you should not expect that everytime you have
a question someone will directly give a solution for it.  It was perfectly
possible to find a solution from what i answered.

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

Post a reply to this message

Christoph wrote:
>Marc-Hendrik Bremer wrote:
>> Wouldn't it be good to mention "accuracy" in this VFAQ-Answer, too?
>
>For what reason? I don't remember many people having problems with 
>that, and the meaning is pretty self explanatory.

There is a plobrem on "accuracy" if the thickness of the isosurface 
is thinner than the accuracy value.  For example, following isosurface 
will generate artifacts(artefacts). 

isosurface {
        function {-0.002+abs(-3.0+f_r(x,y,z))}
        contained_by { sphere { 0, 3.1 } } 
        accuracy 0.01                      
}

Thus if the isosurface has a fine-structure, the "accuracy" value 
should be less than the size of the fine-structure.

R. Suzuki

Post a reply to this message

"R. Suzuki" wrote:
> 
> There is a plobrem on "accuracy" if the thickness of the isosurface
> is thinner than the accuracy value.  For example, following isosurface
> will generate artifacts(artefacts).
> 
> isosurface {
>         function {-0.002+abs(-3.0+f_r(x,y,z))}
>         contained_by { sphere { 0, 3.1 } }
>         accuracy 0.01
> }
> 
> Thus if the isosurface has a fine-structure, the "accuracy" value
> should be less than the size of the fine-structure.
> 

Yes, it seems quite natural, same happens when tesselating such
isosurfaces.  I think there is nothing you can do about it.

BTW, you can create nice moire-like patterns with that method. :-)

Christoph

-- 
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other 
things on: http://www.schunter.etc.tu-bs.de/~chris/

Post a reply to this message