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29 Nov 2024 23:28:16 EST (-0500)
  object bending question (Message 1 to 7 of 7)  
From: Rick D 
Subject: object bending question
Date: 11 Mar 2005 18:26:01
Message: <58a431d4cihtcm57fsaonmok2np251mta5@4ax.com>
Hi,

I'm trying to figure out how to bend objects. For example bend a
cylinder to make the two ends meet, and make it look like a donut. Or
stretch a sphere ( scale <0.3, 0.3, 1.0> ) and lock the two far points
and push it upwards in the middle, so it looks like a banana.

It's probably easy if you know what to look for, but right now i have
nog clue where to start.

Thanks in advance for any help on this.

Best regards,
Rick D.


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From: Rafal Maj Raf256
Subject: Re: object bending question
Date: 11 Mar 2005 18:41:29
Message: <10290181.oGJdq5aqZn@raf256com>
Rick D. wrote:

> It's probably easy if you know what to look for, but right now i have
> nog clue where to start.
> 


In fact rather not - bending/wrapping geometry is much harder then doing it
with textures.

Best would be to have geomtery as isosurface, and then use some function s
to _realy_ bend the shape. It could get very slow in rendering so You might
also want to tesselate resulting isosurface into triangles to speed up
final rendering.

-- 
Rafal Maj Raf256


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From: Alain
Subject: Re: object bending question
Date: 11 Mar 2005 21:21:27
Message: <42325227$1@news.povray.org>
Rick D. nous apporta ses lumieres en ce 2005-03-11 18:26:
> Hi,
> 
> I'm trying to figure out how to bend objects. For example bend a
> cylinder to make the two ends meet, and make it look like a donut.
That's a torus. torus{MajorRadius, MinorRadius [transformation][texture]}. The center
is at <0,0,0>, 
around the y axis on the x-z plane.

> Or stretch a sphere ( scale <0.3, 0.3, 1.0> ) and lock the two far points
> and push it upwards in the middle, so it looks like a banana.
You need an isosurface. Disturb the Y value to make the curve. Divide the x and z
values by 0.3 to 
scale as you mention.
> 
> It's probably easy if you know what to look for, but right now i have
> nog clue where to start.
> 
> Thanks in advance for any help on this.
> 
> Best regards,
> Rick D. 
> 

Alain


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From: Thomas de Groot
Subject: Re: object bending question
Date: 12 Mar 2005 03:17:26
Message: <4232a596@news.povray.org>
"Rick D." <no### [at] mailcom> schreef in bericht
news:58a431d4cihtcm57fsaonmok2np251mta5@4ax.com...
> Hi,
>
> I'm trying to figure out how to bend objects.


bend.inc by Chris Colefax.

Thomas


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From: Warp
Subject: Re: object bending question
Date: 12 Mar 2005 04:13:37
Message: <4232b2c1@news.povray.org>
Alain <ele### [at] netscapenet> wrote:
> > Or stretch a sphere ( scale <0.3, 0.3, 1.0> ) and lock the two far points
> > and push it upwards in the middle, so it looks like a banana.
> You need an isosurface. Disturb the Y value to make the curve. Divide the x and z
values by 0.3 to 
> scale as you mention.

  I believe that what he meant is that he wants to take *any* given object,
regardless of what it is, and bend it. He just gave two illustrative
examples to demonstrate the effect he wants, not meaning he actually
wants to bend precisely these two objects in question.
  Isosurfaces are not really the answer (besides, technically what you
are proposing is not *bending* the isosurface, it's just creating another
isosurface which looks like a bent version of the original).

  The general answer is that it's not possible. See more on this at:
http://tag.povray.org/povQandT/languageQandT.html#bending

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: Florian Brucker
Subject: Re: object bending question
Date: 12 Mar 2005 10:05:07
Message: <42330523@news.povray.org>
If you need only bent cylinders and boxes, try moreshapes.inc from 
http://www.wikipov.org/ow.asp?MoreShapes


HTH,
Florian


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From: brandon
Subject: Re: object bending question
Date: 28 Mar 2005 03:45:01
Message: <web.4247c3661b25e3ea52b8d70@news.povray.org>
Gotta throw in a reference to sphere_sweep in here. You could make a
bannana or any object with a spherical cross section like that (before
scaling of
course).


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