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18 Nov 2024 12:16:48 EST (-0500)
  creating a partially elevated surface (Message 1 to 7 of 7)  
From:
Subject: creating a partially elevated surface
Date: 18 Aug 2002 04:19:32
Message: <3d5f5894@news.povray.org>
Hi, I posted this in the povray.newusers section already, but it was said
that it was hard to visualize what I meant and that perhaps I should post my
question here with a little picture... so here it goes:

can I create a surface that is elevated in the center but has edges that are
in one plane? is this possible with CSG or are there other ways?

thnx a lot in advance,

Daan


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From: Ib Rasmussen
Subject: Re: creating a partially elevated surface
Date: 18 Aug 2002 05:11:12
Message: <3D5F648D.3010805@ibras.dk>
> can I create a surface that is elevated in the center but has edges that are
> in one plane? is this possible with CSG or are there other ways?

If you want it to bulge up in the middle, I think it would be difficult 
to do in CSG. I would try Bezier patches. 4 patches might do it, 
depending on how complex a shape you want.

/Ib


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From:
Subject: Re: creating a partially elevated surface
Date: 18 Aug 2002 05:29:07
Message: <3d5f68e3$1@news.povray.org>
yes, I would like it to bulge up in the middle... I've never worked with
Bezier patches, but judging from the documentation it might be possible, if
I could figure out how to make the edges curved in such a way that they
follow the intersection of two spheres.... I guess I'll just forget about it
for now and get to that when I have somewhat more time to figure out all the
necessary calculations...
thnx for the info

"Ib Rasmussen" <ib### [at] ibrasdk> wrote in message
news:3D5### [at] ibrasdk...
> > can I create a surface that is elevated in the center but has edges that
are
> > in one plane? is this possible with CSG or are there other ways?
>
> If you want it to bulge up in the middle, I think it would be difficult
> to do in CSG. I would try Bezier patches. 4 patches might do it,
> depending on how complex a shape you want.
>
> /Ib
>


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From: Remco de Korte
Subject: Re: creating a partially elevated surface
Date: 18 Aug 2002 07:55:19
Message: <3D5F8A55.53F591B5@onwijs.com>
You might try a heightfield.


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From: Martin Magnusson
Subject: Re: creating a partially elevated surface
Date: 18 Aug 2002 08:17:14
Message: <3D5F9042.4010301@frustratedhousewives.zzn.com>

> I guess I'll just forget about it
> for now and get to that when I have somewhat more time to figure out all the
> necessary calculations...

If you don't enjoy fiddling around with parameters and calculation, you 
could try modelling it in HamaPatch (http://www.hamapatch.t2u.com/)

/ martin


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From: Tony LaVigne
Subject: Re: creating a partially elevated surface
Date: 18 Aug 2002 20:45:12
Message: <web.3d603e923cc842f988d4e3910@news.povray.org>
INVALID_ADDRESS wrote:
>Hi, I posted this in the povray.newusers section already, but it was said
>that it was hard to visualize what I meant and that perhaps I should post my
>question here with a little picture... so here it goes:
>
>can I create a surface that is elevated in the center but has edges that are
>in one plane? is this possible with CSG or are there other ways?
>
>thnx a lot in advance,
>
>Daan
>
Daan,
Below is a link to some code I wrote.
http://www.xenomechanics.com/POVRAY/boat_bulge2.html

  The idea was to make your boat with triangles.  All vertices would either
be on the boundry that are your 2 circles or on  the plane symetry( on the
keel).

  The smooth_triangle call uses normals for the vertices.  The vertices on
the symetrical plane would be straight up middleNormal = <0,1,0>;
 and the vertices along the boundry would be tilted outward,
boundryNormal=<0,cos(90),sin(90)>
but the normals on the model are not being set to these above boundry
conditions and I'm not sure what's wrong.

The profile (looking from the top) seems to be correct and there is
continuity of the whole model.  But it's not quite there yet.

I appoligize if I haven't posted all this correctly as I'm still new to
Povray.
Let me know what you think
Tony


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From:
Subject: Re: creating a partially elevated surface
Date: 19 Aug 2002 02:04:44
Message: <3d608a7c@news.povray.org>
thank you heaps...
the pic looks really promising, I'll look into it when I've got some time
again... again, thank you _a lot_ for your time and effort...


"Tony LaVigne" <ton### [at] xenomechanicscom> wrote in message
news:web.3d603e923cc842f988d4e3910@news.povray.org...
> INVALID_ADDRESS wrote:
> >Hi, I posted this in the povray.newusers section already, but it was said
> >that it was hard to visualize what I meant and that perhaps I should post
my
> >question here with a little picture... so here it goes:
> >
> >can I create a surface that is elevated in the center but has edges that
are
> >in one plane? is this possible with CSG or are there other ways?
> >
> >thnx a lot in advance,
> >
> >Daan
> >
> Daan,
> Below is a link to some code I wrote.
> http://www.xenomechanics.com/POVRAY/boat_bulge2.html
>
>   The idea was to make your boat with triangles.  All vertices would
either
> be on the boundry that are your 2 circles or on  the plane symetry( on the
> keel).
>
>   The smooth_triangle call uses normals for the vertices.  The vertices on
> the symetrical plane would be straight up middleNormal = <0,1,0>;
>  and the vertices along the boundry would be tilted outward,
> boundryNormal=<0,cos(90),sin(90)>
> but the normals on the model are not being set to these above boundry
> conditions and I'm not sure what's wrong.
>
> The profile (looking from the top) seems to be correct and there is
> continuity of the whole model.  But it's not quite there yet.
>
> I appoligize if I haven't posted all this correctly as I'm still new to
> Povray.
> Let me know what you think
> Tony
>


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