Exploring the opposition of Lobel frames

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Exploring the opposition of Lobel frames

Postby Eric » Sat Oct 02, 2021 2:44 am

Back in time last May.
I have experimented with the opposition of identical modules.
Specifically here for each construction, two identical and simple Lobel frames (a central polygon (triangle, square, pentagon, hexagon, heptagon, octagon) surrounded by 1, 3 or 5 rows of triangles).
Opposed and rotated slightly to align the vertices of the central polygon with the sides of the central polygon of the opposite Lobel frame.

EDIT : [Howto] for the one with the heptagonal base.

For the one with a triangular base, if we only put one row of triangles, that makes the basic icosahedron ;-)

20210525_143806.jpg

The observations I made:
The fewer sides the central polygon has, the higher the shape obtained will be.
Conversely, the more sides the central polygon has, the more the final shape will be large and flattened, and therefore the more the angles of the join between the two Lobel frames will be closed.

20210525_143641.jpg
20210525_143712.jpg
Last edited by Eric on Sun Feb 26, 2023 11:42 pm, edited 3 times in total.
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Re: Exploring the opposition of Lobel frames

Postby Eric » Sat Oct 02, 2021 2:47 am

20210525_143227.jpg
20210525_143433.jpg
20210525_143351.jpg
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Re: Exploring the opposition of Lobel frames

Postby Eric » Sat Oct 02, 2021 2:51 am

Admittedly, a Lobel frame with a hexagonal base is completely flat,
20210525_022626.jpg

but when you put two in opposition, slightly turned relative to each other, the result is not flat at all !!!
20210525_105810.jpg

20210525_103122.jpg
Last edited by Eric on Sat Oct 02, 2021 3:24 am, edited 1 time in total.
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Re: Exploring the opposition of Lobel frames

Postby Eric » Sat Oct 02, 2021 3:00 am

Hexagonal base:
20210525_105702.jpg
Heptagonal base:
20210517_223300.jpg
Octagonal base:
20210518_185447.jpg
Look at those wavy shapes 8-)
No need to go further, because from the enneagone and above, the angles are too closed between the 2 Lobel frames (I already cheated with the octogonal-base Lobel Frames by using bigger spheres on the edges).
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Re: Exploring the opposition of Lobel frames

Postby Peter Jepsen » Tue Oct 12, 2021 8:57 pm

Very very nice research work Eric! Both structurally and visually pleasing to admire. Compliments!!

I am trying to mentally ping-pong modular ideas off of your shapes but so far I've come up blank. They do look very nice by themselves too though. :)

As far as I know, the flat top of the heptagon is the _first_ reinforced flat heptagonal polygon shape I have ever seen with Geomag. :)

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Re: Exploring the opposition of Lobel frames

Postby Wagyx » Sun Feb 26, 2023 1:05 pm

Hey there,
I have managed to turn the larger models into 3D models, you will find them attached.
If anyone is interested, I can also do it with the smaller models.

I also got access from the owner of the Lobel frame website to all the 3D models that were computed by Alain Lobel.
You may view them on my website: https://asliceofcuriosity.fr/blog/posts/geometry6.html
I don't have a web viewer with rods, plates and balls from Geomag yet so I can't display them like Stella does.
If anyone has reference models for that I can try making the viewer.
Attachments
lobel-frame-opposite.zip
contains obj and stella files
(74.68 KiB) Downloaded 78 times
Last edited by Wagyx on Tue May 23, 2023 5:18 pm, edited 1 time in total.
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Re: Exploring the opposition of Lobel frames

Postby Wagyx » Sun Feb 26, 2023 1:07 pm

Here are some pictures generated with Stella.
Attachments
lobel-frame-opposite5_000.png
lobel-frame-opposite4_000.png
lobel-frame-opposite3_000.png
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Re: Exploring the opposition of Lobel frames

Postby Wagyx » Sun Feb 26, 2023 1:09 pm

Some more pictures.
Attachments
lobel-frame-opposite8_000.png
lobel-frame-opposite7_000.png
lobel-frame-opposite6_000.png
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Re: Exploring the opposition of Lobel frames

Postby Eric » Sun Feb 26, 2023 4:47 pm

Wow! What a fantastic job you did!

First of all, welcome to you.
I would be curious to see some photos of your achievements in supermags. On your website, there's just a thumbnail giving an overview of some shapes on your coffee table ;)

Your collection of Lobel frame models is very handy. The fact of being able to visualize them by whole pages in manipulable 3D frames is awesome. It will certainly be a gold mine for new building ideas. :D

Alain Lobel's website seems no longer accessible. It's a wonderful idea to have contacted his family and obtained permission to build this library. You really did a great great job (which must have taken you a lot of time).

Now, all we have to do is get the rods and spheres out of our drawers!
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Re: Exploring the opposition of Lobel frames

Postby Wagyx » Sun Feb 26, 2023 5:45 pm

Thank you very much, Eric.

Regarding the pictures of the models, as you can imagine, I had to dismantle many of them to make new ones and explore new combinations but I rarely take pictures.
I sometimes find it difficult to properly grasp the structure of the models with pictures only, that's why, each time I have made a model, I've also made its 3D equivalent. It acts as a blueprint.
This way, I can display the model online through my web viewer or share the file with people.
I am also working on some code to combine models together to make bigger shapes or make ones that would be impossible to build because of the minimum angle between two edges.
I could envision to make very realistic renders (using Blender) if I get access to the models for the Supermag or Geomag rods.
For the moment, I use Stella to this end.
I could also publish on this forum one picture per day, I think I could hold it for a year, would that be a good idea ?

Regarding the Lobel Frames, I have both the source code in old BASIC files that generates the models which I have trouble understanding and running properly and models in some old 3D format.
I have managed to make scripts to convert them to obj files for the website.
My goal is to remake the generating scripts for each family and maybe discover new ones like the one your berlingot would belongs to.
I'll get in touch with Lobel's family regarding the website.

In the meantime, here are pictures I have just taken.
Attachments
IMG_9076.JPG
IMG_9075.JPG
IMG_9073.JPG
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