Christopher James Huff <chr### [at] maccom> wrote:
> The output will be identical. It is just that the built-in feature will 
> always get the vertices right, while your duplicate-removal code might 
> have a bug.

  It's often the case that you can build the mesh without creating
duplicate vertex points at all. This way you don't have to remove anything.
  For example, if you make a box using mesh2, you simply create 8 points
in the vertex list and then use their index values in the faces list.
Similarly for more advanced shapes, usually created using loops (such
as cylinders, spheres, etc).

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -

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"Shay" <sah### [at] simcopartscom> wrote in news:3d89f074@news.povray.org:

> 
> Christopher James Huff <chr### [at] maccom> wrote in message
> news:chr### [at] netplexaussieorg...
>>
>> <snip>while your duplicate-removal code might
>> have a bug.
>>
> In this case it's just too simple to f__k up.

Uh? What is this function? In which include file can I find it?
Does it look nice, used in an isosurface?
:-P

-- 
--=#=--=#=--=#=--=#=--=#=--=#=--=#=--=#=--=#=--
Philippe Lhoste (Paris -- France)
Professional programmer and amateur artist
http://jove.prohosting.com/~philho/

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On Wed, 18 Sep 2002 15:38:31 +0200, Jellby <jel### [at] M-softhomenet> wrote:
> > > Is it possible with the
> > > current tools to define a sort of hybrid between a lathe and a prism?
> > 
> > http://www.econym.demon.co.uk/isotut/splines.htm
> > prismatic lathe
> > 
> > Ingo
>
> Yeah, I should have thought of isosurfaces :)

It is not isosurface object, it is parametric object. It is not exactly the
same. And if something is possible with parametric object then it is possible
with mesh. Look at http://members.home.nl/seedseven/

ABX

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Philippe Lhoste <Phi### [at] GMXnet> wrote in message
news:Xns### [at] 204213191226...
> "Shay" <sah### [at] simcopartscom> wrote in news:3d89f074@news.povray.org:

> > In this case it's just too simple to f__k up.
>
> Uh? What is this function? In which include file can I find it?
> Does it look nice, used in an isosurface?
> :-P
>

This function can be found in many of my personal *.inc files. Output is a
harsh gong-type noise and a yellow highlight over one line of code.
Isosurface version produces an isosurface the exact shape and scale of the
bounding container.

 -Shay

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ABX wrote:

> On Wed, 18 Sep 2002 15:38:31 +0200, Jellby <jel### [at] M-softhomenet>
> wrote:
>> > > Is it possible with the
>> > > current tools to define a sort of hybrid between a lathe and a prism?
>> > 
>> > http://www.econym.demon.co.uk/isotut/splines.htm
>> > prismatic lathe
>> > 
>> > Ingo
>>
>> Yeah, I should have thought of isosurfaces :)
> 
> It is not isosurface object, it is parametric object. It is not exactly
> the same. And if something is possible with parametric object then it is
> possible with mesh. Look at http://members.home.nl/seedseven/
> 
> ABX

Yes, now I have read the whole tutorial (I just had a quick look before). I 
see the difference between isosurfaces and parametric objects. And yes, 
almost everything is possible with meshes, but it's not the same, from my 
point of view it's just a fake, a useful, efficient, clever fake, but a 
fake.

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On Fri, 20 Sep 2002 20:00:31 +0200, Jellby <jel### [at] M-softhomenet> wrote:
> Yes, now I have read the whole tutorial (I just had a quick look before). I 
> see the difference between isosurfaces and parametric objects. And yes, 
> almost everything is possible with meshes, but it's not the same, from my 
> point of view it's just a fake, a useful, efficient, clever fake, but a 
> fake.

Is approximation a fake in your definition ?

ABX

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Jellby <jel### [at] M-softhomenet> wrote in message
news:3d8b623e@news.povray.org...

< And yes,
> almost everything is possible with meshes, but it's not the same, from my
> point of view it's just a fake, a useful, efficient, clever fake, but a
> fake.

I'd better get on the phone to Pixar right away!! <g>

 -Shay

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ABX wrote:

> On Fri, 20 Sep 2002 20:00:31 +0200, Jellby <jel### [at] M-softhomenet>
> wrote:
>> Yes, now I have read the whole tutorial (I just had a quick look before).
>> I see the difference between isosurfaces and parametric objects. And yes,
>> almost everything is possible with meshes, but it's not the same, from my
>> point of view it's just a fake, a useful, efficient, clever fake, but a
>> fake.
> 
> Is approximation a fake in your definition ?
> 
> ABX

Don't misunderstand me. Maybe 'fake' was not a very well-chosen word (I'm 
not an English speaker). I meant that meshes are not the 'true' object (if 
you are approximating an object by means of a mesh), if you zoom it you 
will eventually see the triangles in the shadow, and they are not quite 
'elegant', I think... We do have true spheres in povray, and they can be 
made as meshes too. I was just wondering if it would be possible to have 
such prismatic lathes in an optimized way (parametrics are slow, I've 
heard), without the need of converting to a mesh. I don't demand it, I 
can't do that and I don't want to do that, I was just giving an idea.

After all, everything in povray is just a fake of reality ;)

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On Fri, 20 Sep 2002 22:27:17 +0200, Jellby <jel### [at] M-softhomenet> wrote:
> > Is approximation a fake in your definition ?
>
> Don't misunderstand me. Maybe 'fake' was not a very well-chosen word (I'm 
> not an English speaker). I meant that meshes are not the 'true' object (if 
> you are approximating an object by means of a mesh).

When I asked above question I tried to point you that surfaces of isosurface
and parametric objects are approximations. You can control accuracy of this
approximation with max_gradient, accuracy and evaluate keywords. You can
control accuracy of the mesh with vertex resolution. So isosurface is a fake,
"a useful, efficient, clever fake, but a fake" quoting you. It is better
approximation becouse of its alogithms but for the same reason it is usually
slower.

> After all, everything in povray is just a fake of reality ;)

and animation features are just a fake of real movie www.POVtheMOVIE.com ;)

ABX

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ABX wrote:

> When I asked above question I tried to point you that surfaces of
> isosurface and parametric objects are approximations. You can control
> accuracy of this approximation with max_gradient, accuracy and evaluate
> keywords.

I had the feeling that was what you meant ;)

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