POV-Ray : Newsgroups : povray.newusers : Need cone-function for isosurface Server Time
5 Sep 2024 16:18:06 EDT (-0400)
  Need cone-function for isosurface (Message 1 to 4 of 4)  
From: Marc-Hendrik Bremer
Subject: Need cone-function for isosurface
Date: 19 Sep 2000 17:30:39
Message: <39c7daff$1@news.povray.org>
Hi,

I don't feel as good, asking for isosurface-functions in .newusers, but this
could be that trivial that I do not dare to ask in one of the other groups.

I need a function which represents a cone (with one of the radii =0) in an
isosurface. I tried to "generate" one using the cylinder function (x*x
+z*z -r*r) and modifying the radius by y. That is probably the right way,
but I don't know how to do it right. Everything I can get is a somewhat
parabolic-shape. My math is already to rusty.

Thanks in advance,

Marc-Hendrik


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From: Chris Huff
Subject: Re: Need cone-function for isosurface
Date: 19 Sep 2000 18:03:41
Message: <chrishuff-EFCF0F.17054119092000@news.povray.org>
In article <39c7daff$1@news.povray.org>, "Marc-Hendrik Bremer" 
<Mar### [at] t-onlinede> wrote:

> I don't feel as good, asking for isosurface-functions in .newusers, 
> but this could be that trivial that I do not dare to ask in one of 
> the other groups.

In general, math questions should go to povray.advanced-users.


> I need a function which represents a cone (with one of the radii =0) 
> in an isosurface. I tried to "generate" one using the cylinder 
> function (x*x +z*z -r*r) and modifying the radius by y. That is 
> probably the right way, but I don't know how to do it right. 
> Everything I can get is a somewhat parabolic-shape. My math is 
> already to rusty.

Sounds like you were using a non-0 value for the threshold...these give 
double-ended cones for me:
function {sqrt(sqr(x) + sqr(z)) - abs(y)}
function {sqrt(sqr(x) + sqr(z) - sqr(y))}

But you must use a threshold of 0.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

<><


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From: Marc-Hendrik Bremer
Subject: Re: Need cone-function for isosurface
Date: 19 Sep 2000 18:30:45
Message: <39c7e915@news.povray.org>
Thank you for the fast answer. I use threshold 0 and so it works for me too
:-).

Marc-Hendrik


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From: Greg M  Johnson
Subject: Re: Need cone-function for isosurface
Date: 27 Sep 2000 08:27:39
Message: <39D1E67D.E1813E9E@my-dejanews.com>
Chris Huff wrote:

> In article <39c7daff$1@news.povray.org>, "Marc-Hendrik Bremer"
> <Mar### [at] t-onlinede> wrote:
>
> > I don't feel as good, asking for isosurface-functions in .newusers,
> > but this could be that trivial that I do not dare to ask in one of
> > the other groups.
>
> In general, math questions should go to povray.advanced-users.

Unless, of course, they are "trivial."


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