Borromean Seifert Surface

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 From:  bemfarmer
7682.1 
A recent Tequila commercial had an interesting voronoi version of a model.
It had three rounded rectangles, with "voronoi webbing" between them.
An extensive google search found it to be Borromean ring based.
There are no free models of these types. The only explanation for how it can be created was "Blender and Meshlab."

Finally an explanation was found. The Surface Evolver program of Ken Brakke may be used to model it with "soap film" mathematics. http://facstaff.susqu.edu/brakke/aux/borromean/borromean.html
The page with mouse spin-able 3D images using WebGL 3D is excellent, and has about 15 variations.
The Surface Evolver *.fe files were not provided.

The data for the Seifert version was processed with Notepad++, and then imported to Moi with a new script based upon Michaels
ImportPointFile script, called ImportTriangleFile. The new script still has a few bugs to fix, due to being an amateur programmer.
The boundary curves appear to be ellipses.

A Surface Evolver *.fe file may be attempted.
Three orthogonal ellipses with a major axis to minor axis Golden ratio, using Moi's Golden snap script were created, but not used yet.







SubDiv9 may be applied.
The three boundary curve polylines could have a circle swept.
I'll have to learn how to do voronoi, as per Stefan, I guess with meshlab.
Ran out of room for .3dm, time to delete some files :-)

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 From:  bemfarmer
7682.2 
Edit: BorromeanSeifert .3dm of 6.5 MB deleted. No one downloaded it.

Uploaded borromean-seifert csv file of 193 kb.
EDIT: Deleted borromean-unorientableONE csv file of 191 kb, due to two missing triangles. Replaced with version TWO in later post.

Also uploaded the ImportTriangleFile script, which is a special purpose script to upload the two csv files above.
The files consist of vertexes of triangle corners. Each line is a vertex (x,y,z). Three sequential vertexes make a triangle.
So a lot of the vertexes are duplicates. The source files are very fast in WebGL memory. These two files are striped down.
There are no normals. The 3 boundary ellipse polylines are not included, but can be selected from the edges and re-created.

A modification of ImportPointFile script, with some LineWeb code grafted in, the ImportTriangleFile script is slow,
so it may have some incorrect code (?), but it works. ObjectList methods for the script were not successful, more study needed :-)
Please allow at lease 5 to 30 seconds after pushing the Done button, for the triangles to load, and for the script to close, on a fast computer.

Now to try saving in Moi as conventional obj files.

- Brian

Looks like the point import option is broken, but the points can be imported with the ImportPointFile script.
The points will have many duplicates...

EDIT: See post 8 for updated _ImportTrianglesCSV script.

EDITED: 1 Nov 2015 by BEMFARMER


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 From:  Frenchy Pilou (PILOU)
7682.3 
A complex surface indeed!

Does the thickness is working on it ?
---
Pilou
Is beautiful that please without concept!
My Gallery
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 From:  bemfarmer
7682.4 In reply to 7682.3 
Hi Pilou

After planar, Moi "Types" indicates the presence of a solid.
There is a small tetrahedral solid, located by a small hole defect in the borromean-unorientable model.
I'll have to check the points involved, or fix it manually.

I do not have the skill to thicken the surfaces.
In the Costa discussion, Stefan mentions "LS3 Loop subdivision," Meshlab, "Dual remeshing," ZBrush-Z Remesher, and Fusion360 T-Splines.

- Brian
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 From:  bemfarmer
7682.5 In reply to 7682.4 
Restored two missing triangles in version borromean-unorientableONE. Solid generated after planar and join is now gone.
Corrected version *TWO.csv attached.
Corrected again, 11/1/2015

- Brian

EDITED: 1 Nov 2015 by BEMFARMER


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 From:  bemfarmer
7682.6 In reply to 7682.5 
script: /* Highlight naked edges */ selects the 3 boundary ellipse polylines.

Subdiv_Beta9 does not work on the unorientable model.

- Brian
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 From:  bemfarmer
7682.7 
This is the Borromean Tetrahedral center surface evolver csv triangle file.
SubDivBeta9 on unjoined planar triangles, at 125.



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 From:  bemfarmer
7682.8 
This script, _ImportTrianglesCSV, is a modification of the P_ImportSTL script., and is about 100 times faster than the previous triangle import script.
It imports one specific kind of file. The files came from surface evolver program.

The CSV file contains only a list of triangle vertices, comma delimited.
There is one vertex per file line, with coordinates x, y, z.
Three file lines defines a triangle by its 3 vertices.

An alert message displays the number of triangles imported. It could be commented out, or maybe have a checkbox?

The total number of vertices in the file should be a multiple of 3.
Otherwise, the last triangle will not be created by loft.

Even though the triangles may be loaded and displayed, failure of the alert message to appear indicates a problem with the file.
This may occur if the last triangle is missing 1 or 2 vertices.
It may also occur if there are extraneous delimiters.

It may be possible to incorporate the delimiter selection of _ImportPointFile script?

- Brian

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 From:  bemfarmer
7682.9 
Two more soap films.

- Brian


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