POV-Ray: Newsgroups: povray.text.scene-files: Object growth macros

POV-Ray : Newsgroups : povray.text.scene-files : Object growth macros		Server Time 1 Nov 2024 03:18:01 EDT (-0400)

From: Redbeard (MDJohnson)
Subject: Object growth macros
Date: 21 Oct 2001 15:20:49
Message: <3bd32011$1@news.povray.org>

Hi all.

I've just finished a set of macros for use in my possible IRTC entry (running
out of time... don't even have basic scene set... uh oh).  I want to be able to
"grow" an object.  That is, expand it by some amount along the normal of all
surfaces, kind of like the grow command in a vector based drawing program.

This little include file does that for the five objects that I could figure out
how to grow.

I'll post a simple example image on p.b.i.

The next question is, can a general method for isosurfaces be had?  I don't
really think so, but I thought I'd ask the question.

Michael
--
#macro M(D,J)text{ttf"cyrvetic.ttf"D 1,0translate-J}#end#macro N(E,K)#local A=
M(E,K)light_source{-z*30rgb 1projected_through{A}}#end N("Michael"<1.6,-.2,5>)
N("Johnson"<1.9.8,5>)sphere{z*9,4pigment{gradient x+y scale 10color_map{[0 rgb
x][1rgb x+y]}sine_wave}} // (c)2001 Michael D Johnson red### [at] wvadelphianet

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From: Redbeard (MDJohnson)
Subject: Re: Object growth macros
Date: 21 Oct 2001 15:23:40
Message: <3bd320bc$1@news.povray.org>

Of course, the include file would be nice :-)

"Redbeard (MDJohnson)" <red### [at] wvadelphianet> wrote in message
news:3bd32011$1@news.povray.org...
> Hi all.
>
> I've just finished a set of macros for use in my possible IRTC entry (running
> out of time... don't even have basic scene set... uh oh).  I want to be able
to
> "grow" an object.  That is, expand it by some amount along the normal of all
> surfaces, kind of like the grow command in a vector based drawing program.
>
> This little include file does that for the five objects that I could figure
out
> how to grow.
>

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Attachments:
Download 'growobj.inc.txt' (2 KB)

From: s1631001
Subject: Re: Object growth macros
Date: 29 Nov 2001 13:58:34
Message: <3C068572.7BCCD511@namtar.qub.ac.uk>

"Redbeard (MDJohnson)" wrote:
> The next question is, can a general method for isosurfaces be had?
Changing the threhsold value would accomplish this, wouldn't it? I've
only just started fiddling with isosurfaces, so don't take my word for
it...

-- 
signature{
  "Grey Knight"
  contact{
    email "gre### [at] yahoocom"
  }
  site_of_week{
    url "http://mathworld.wolfram.com"
  }
}

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From: Jan Walzer
Subject: Re: Object growth macros
Date: 30 Nov 2001 12:29:07
Message: <3c07c1e3@news.povray.org>

"s1631001" <s16### [at] namtarqubacuk> wrote
> Changing the threhsold value would accomplish this, wouldn't it? I've
> only just started fiddling with isosurfaces, so don't take my word for
> it...

only if the gradient of the function remains everywhere the same ....
... which is quite seldom the case ...

That is quite the same, I asked a while ago in another group:
... if there is a way to determin to a given function another function, that
has its surface in a constant distance of the original function, even if the



--
Jan Walzer <jan### [at] lzernet>

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