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14 Aug 2024 17:58:25 EDT (-0400)
  Geodesic Dome (Message 1 to 8 of 8)  
From: JPGargoyle
Subject: Geodesic Dome
Date: 7 Sep 2002 22:59:26
Message: <3d7abd0e@news.povray.org>
Hi all.

I want to do a Geodesic Dome, so I have searched the net for the formulas.

All I've found was a bunch of mathmatical formulas I don't understand and in
one site I've found a pre-made GeoDome with the coords of the vertices. (see
GeodesicDomeTest1.jpg)

But since this wasn't enough for what I wanted, I've wrote a macro to sub
divide the triangles, and this is the result.:
GeodesicDomeTest2.jpg  --> 1 subdivision
GeodesicDomeTest3.jpg  --> 2 subdivisions
GeodesicDomeTest4.jpg  --> 3 subdivisions

Todo next:  wireframe to go with the vertices


Best regards


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Attachments:
Download 'GeodesicDomeTest1.jpg' (65 KB) Download 'GeodesicDomeTest2.jpg' (43 KB) Download 'GeodesicDomeTest3.jpg' (59 KB) Download 'GeodesicDomeTest4.jpg' (69 KB)

Preview of image 'GeodesicDomeTest1.jpg'
GeodesicDomeTest1.jpg

Preview of image 'GeodesicDomeTest2.jpg'
GeodesicDomeTest2.jpg

Preview of image 'GeodesicDomeTest3.jpg'
GeodesicDomeTest3.jpg

Preview of image 'GeodesicDomeTest4.jpg'
GeodesicDomeTest4.jpg


 

From: Herman Serras
Subject: Re: Geodesic Dome
Date: 8 Sep 2002 08:32:54
Message: <3D7B43B9.83EE483A@pandora.be>
JPGargoyle wrote:
> 
> Hi all.
> 
> I want to do a Geodesic Dome, so I have searched the net for the formulas.
> 
> All I've found was a bunch of mathmatical formulas I don't understand and in
> one site I've found a pre-made GeoDome with the coords of the vertices. (see
> GeodesicDomeTest1.jpg)

I suppose you didn't see Uwe Zimmermann's 1999 include file geodesic.inc
that also defines macros to determine a geodesic division on a sphere.
That's a lot more than "a pre-made geodome with the coords of the
vertices".
If possible: I'm interested in your macros.

> 
> But since this wasn't enough for what I wanted, I've wrote a macro to sub
> divide the triangles, and this is the result.:
> GeodesicDomeTest2.jpg  --> 1 subdivision
> GeodesicDomeTest3.jpg  --> 2 subdivisions
> GeodesicDomeTest4.jpg  --> 3 subdivisions
> 
> Todo next:  wireframe to go with the vertices
> 
> Best regards
> 
>  [Image]
> 
>  [Image]
> 
>  [Image]
> 
>  [Image]

-- 
Herman Serras
Gent (Belgium)
http://cage.rug.ac.be/~hs/


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From: Hugo
Subject: Re: Geodesic Dome
Date: 8 Sep 2002 11:12:53
Message: <3d7b68f5@news.povray.org>
>Uwe Zimmermann's 1999 include file geodesic.inc

I have his macro and it works, but it doesn't output a mesh2 or something
that can easily be converted to mesh2. This nags me.

I like your subdivision however. It gives a nice shape. Do you think your
macro could be used to subdivide any array of points?

Regards,
Hugo


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From: JPGargoyle
Subject: Re: Geodesic Dome
Date: 8 Sep 2002 12:48:03
Message: <3d7b7f43$1@news.povray.org>
> I suppose you didn't see Uwe Zimmermann's 1999 include file geodesic.inc
> that also defines macros to determine a geodesic division on a sphere.
> That's a lot more than "a pre-made geodome with the coords of the
> vertices".

Nope. I havn't heard of it until now, but I'm interested in taking a look at
it.
Can you please tell me where I can take a look at it? Thanks.


> If possible: I'm interested in your macros.
I have posted the sources at povray.binaries.scene-files. :)
Please notice that it wasn't made with the possibility of being posted so it
is not optimized and might be confusing because my approach isn' the best at
all. Its just a test in its early stages of development.

But if you neet to ask something feel to do it.


Best regards.


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From: JPGargoyle
Subject: Re: Geodesic Dome
Date: 8 Sep 2002 12:54:49
Message: <3d7b80d9$1@news.povray.org>
> I like your subdivision however. It gives a nice shape. Do you think your
> macro could be used to subdivide any array of points?

hmmm. They will have to be arranged in sets of three, because it is made to
subdivide triangles.
You probably will have to modify it a lot because it doesn't take into
consideration any normals information.
And I think it just works this fine on this example becauseall the triangles
sub-divided have the 3 sides with almost the same length, but you can try it
with trinagles with different proportions (I havn't tryed it yet)

The points here appear at the surface of the sphere because the sphere is
centered at the origin and I translate the point into a distance from the
center of the sphere equal to the radius of the sphere (in this case 1).


Best regards.


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From: Herman Serras
Subject: Re: Geodesic Dome
Date: 9 Sep 2002 02:27:32
Message: <3D7C3F9A.843C856D@pandora.be>
A search on the povray site resulted in

http://www.geocities.com/SiliconValley/Lakes/5432/povray/geodesic.html


JPGargoyle wrote:
> 
> > I suppose you didn't see Uwe Zimmermann's 1999 include file geodesic.inc
> > that also defines macros to determine a geodesic division on a sphere.
> > That's a lot more than "a pre-made geodome with the coords of the
> > vertices".
> 
> Nope. I havn't heard of it until now, but I'm interested in taking a look at
> it.
> Can you please tell me where I can take a look at it? Thanks.
> 
> > If possible: I'm interested in your macros.
> I have posted the sources at povray.binaries.scene-files. :)
> Please notice that it wasn't made with the possibility of being posted so it
> is not optimized and might be confusing because my approach isn' the best at
> all. Its just a test in its early stages of development.
> 
> But if you neet to ask something feel to do it.
> 
> Best regards.

-- 
Herman Serras
Gent (Belgium)
http://cage.rug.ac.be/~hs/


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From: JPGargoyle
Subject: Re: Geodesic Dome
Date: 9 Sep 2002 07:35:03
Message: <web.3d7c86c0c6ede976641f1e9f0@news.povray.org>
Herman Serras wrote:
>A search on the povray site resulted in
>
>http://www.geocities.com/SiliconValley/Lakes/5432/povray/geodesic.html
>
>

Thanks a lot. :)


Best regards.


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From: J  Diehl
Subject: Re: Geodesic Dome
Date: 12 Sep 2002 13:45:09
Message: <web.3d80d15bc6ede976717ea7a0@news.povray.org>
Here is a quick and dirty geodome I developed. The easiest code to get the
shape, I think. Dirty, because spheres and cylinders are drawn several
times. This is because the algorithm was developed to create a mesh and not
a wireframe model.
I don't know the exact definition of a geodesic dome, but all I heard about
it my shape seems to be one: the algorithm starts with an octahedron with 6
points and 8 triangles. Every triangle is recursively divided into four new
ones and each new point is projected onto the surface of the sphere.
So can anybody tell me if this is one?

//basic values
#declare node_rad=0.1;
#declare link_rad=0.04;
#declare dome_rad=3;
#declare dome_rec_depth=3;

//recursive geodesic triangle subdivision
#macro tri1(a,b,c,depth)
    #if (depth < dome_rec_depth)
        #local ab= vnormalize(a+b)*dome_rad;
        #local bc= vnormalize(b+c)*dome_rad;
        #local ca= vnormalize(c+a)*dome_rad;
        tri1(bc,ca,ab,depth+1)
        tri1(a,ab,ca,depth+1)
        tri1(ab,b,bc,depth+1)
        tri1(ca,bc,c,depth+1)
    #else
        sphere{a, node_rad}
        sphere{c, node_rad}
        cylinder{a,b,link_rad}
        cylinder{b,c,link_rad}
        cylinder{c,a,link_rad}
    #end
#end

//declare corners of octahedron
#declare v1=-x * dome_rad;
#declare v2=-y * dome_rad;
#declare v3= x * dome_rad;
#declare v4= y * dome_rad;
#declare v5= z * dome_rad;
#declare v6=-z * dome_rad;

//draw scene
camera{location < 5,6,-3> look_at < 0,0,0>}
light_source {< -90,140,-190>  color rgb 1}

union{
    tri1(v1,v2,v5,0)
    tri1(v2,v3,v5,0)
    tri1(v3,v4,v5,0)
    tri1(v4,v1,v5,0)
    tri1(v1,v2,v6,0)
    tri1(v2,v3,v6,0)
    tri1(v3,v4,v6,0)
    tri1(v4,v1,v6,0)
    pigment{color rgb < 1,0.8,0.5>}
    finish{specular 1}
    }


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