POV-Ray : Newsgroups : povray.binaries.images : Star shapes (15kb + 86kb) Server Time
4 Nov 2024 17:29:57 EST (-0500)
  Star shapes (15kb + 86kb) (Message 1 to 9 of 9)  
From: Kevin Jackson-Mead
Subject: Star shapes (15kb + 86kb)
Date: 23 Aug 2000 19:36:30
Message: <39A45F4B.64C87A56@mindspring.com>
I made the following images with a little macro (available on my web
page) that creates star-shaped prisms.  I made the macro in order to
make one of those "NEW AND IMPROVED" stickers that appear on products.
I'm in the process of making my first IRTC entry, and it is for that.
I'm not sure if I'll finish it or not, but it's nice to actually have a
goal instead of just screwing around.  It helps motivate me.

Kevin Jackson-Mead
http://www.mindspring.com/~jacksonmead


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Attachments:
Download 'startest.png' (16 KB) Download 'weird.png' (86 KB)

Preview of image 'startest.png'
startest.png

Preview of image 'weird.png'
weird.png


 

From: Kevin Jackson-Mead
Subject: Re: Star shapes (15kb + 86kb)
Date: 23 Aug 2000 19:45:06
Message: <39A46184.2B767F8F@mindspring.com>
Seems I'm always forgetting stuff.  The first image should be fairly
self-explanatory.  The second image is a star with 1123 points (no
significance in the number, I just wanted to try something large).  As you can
see, some weird stuff is going on.  Any ideas exactly what's causing it?

Kevin Jackson-Mead
http://www.mindspring.com/~jacksonmead


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From: Kari Kivisalo
Subject: Re: Star shapes (15kb + 86kb)
Date: 23 Aug 2000 20:45:35
Message: <39A4704B.EA5AAAF8@kivisalo.net>
Kevin Jackson-Mead wrote:
>
> see, some weird stuff is going on.  Any ideas exactly what's causing it?

Aliasing. Too low sampling frequency folds high frequencies over lower
frequencies. Cure: +a0.1 +r5 or render at 2x,3x, etc. resolution and
sample down.

______________________________________________________________________
Kari Kivisalo                                  http://www.kivisalo.net


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From: Kevin Jackson-Mead
Subject: Re: Star shapes (15kb + 86kb)
Date: 23 Aug 2000 21:57:11
Message: <39A48079.490D2CB2@mindspring.com>
Kari Kivisalo wrote:

> Kevin Jackson-Mead wrote:
> >
> > see, some weird stuff is going on.  Any ideas exactly what's causing it?
>
> Aliasing. Too low sampling frequency folds high frequencies over lower
> frequencies. Cure: +a0.1 +r5 or render at 2x,3x, etc. resolution and
> sample down.
>
> ______________________________________________________________________
> Kari Kivisalo                                  http://www.kivisalo.net

Got it.  Thanks.  The unintended "folding" is kind of neat, though.  Might
have to experiment with that.

Kevin Jackson-Mead
http://www.mindspring.com/~jacksonmead


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From: Steve
Subject: Re: Star shapes (15kb + 86kb)
Date: 24 Aug 2000 11:18:05
Message: <slrn8qae3m.7ov.steve@zero-pps.localdomain>
On Wed, 23 Aug 2000 19:33:31 -0400, Kevin Jackson-Mead wrote:
>This is a multi-part message in MIME format.
>--------------28E3F4E06E0E99FB317A2596
>Content-Type: text/plain; charset=us-ascii
>Content-Transfer-Encoding: 7bit
>
>I made the following images with a little macro (available on my web
>page) that creates star-shaped prisms.  I made the macro in order to
>make one of those "NEW AND IMPROVED" stickers that appear on products.
>I'm in the process of making my first IRTC entry, and it is for that.
>I'm not sure if I'll finish it or not, but it's nice to actually have a
>goal instead of just screwing around.  It helps motivate me.

This looks useful.  Thanks for your effort. 

-- 
Cheers
Steve              email mailto:ste### [at] zeroppsuklinuxnet

%HAV-A-NICEDAY Error not enough coffee  0 pps. 

web http://www.zeropps.uklinux.net/

or  http://start.at/zero-pps

 12:26pm  up 2 days, 16:44,  2 users,  load average: 1.04, 1.06, 1.05


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From: Steve
Subject: Re: Star shapes (15kb + 86kb)
Date: 24 Aug 2000 11:18:05
Message: <slrn8qaeer.7ov.steve@zero-pps.localdomain>
On Wed, 23 Aug 2000 19:43:00 -0400, Kevin Jackson-Mead wrote:
>Seems I'm always forgetting stuff.  The first image should be fairly
>self-explanatory.  The second image is a star with 1123 points (no
>significance in the number, I just wanted to try something large).  As you can
>see, some weird stuff is going on.  Any ideas exactly what's causing it?

For the second one, maybe try increasing max_trace_level. 

-- 
Cheers
Steve              email mailto:ste### [at] zeroppsuklinuxnet

%HAV-A-NICEDAY Error not enough coffee  0 pps. 

web http://www.zeropps.uklinux.net/

or  http://start.at/zero-pps

 12:26pm  up 2 days, 16:44,  2 users,  load average: 1.04, 1.06, 1.05


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From: Jérôme Berger
Subject: Re: Star shapes (15kb + 86kb)
Date: 24 Aug 2000 11:39:28
Message: <39A541B1.151B6E4@enst.fr>
Steve wrote:
> 
> For the second one, maybe try increasing max_trace_level.
> 
	Won't help: max_trace_level is only useful when there is reflection or
refraction. The only solution is to increase the resolution (either
directly or through anti-aliasing).


-- 

* Doctor Jekyll had something * mailto:ber### [at] inamecom
* to Hyde...                  * http://www.enst.fr/~jberger
*******************************


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From: Chris Huff
Subject: Re: Star shapes (15kb + 86kb)
Date: 24 Aug 2000 14:15:43
Message: <chrishuff-A154D3.13170824082000@news.povray.org>
In article <39A48079.490D2CB2@mindspring.com>, Kevin Jackson-Mead 
<jac### [at] mindspringcom> wrote:

> Got it.  Thanks.  The unintended "folding" is kind of neat, though.  
> Might have to experiment with that.

It's a sort of moire effect...try making a wood or onion pigment scaled 
*very* small for some other interesting effects.

-- 
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: Kevin Jackson-Mead
Subject: Re: Star shapes (15kb + 86kb)
Date: 24 Aug 2000 14:35:31
Message: <39A56A7A.348BCA41@mindspring.com>
After looking up "moire effect", I tried as you suggested.  Pretty neat.  I
think I'm going to put off experimenting with some more of this until the
current IRTC round is over.  Hopefully I can get a somewhat presentable
first attempt at an entry in.

Kevin Jackson-Mead
http://www.mindspring.com/~jacksonmead

Chris Huff wrote:

> In article <39A48079.490D2CB2@mindspring.com>, Kevin Jackson-Mead
> <jac### [at] mindspringcom> wrote:
>
> > Got it.  Thanks.  The unintended "folding" is kind of neat, though.
> > Might have to experiment with that.
>
> It's a sort of moire effect...try making a wood or onion pigment scaled
> *very* small for some other interesting effects.
>
> --
> Christopher James Huff
> Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
> TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
>
> <><


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