POV-Ray : Newsgroups : povray.binaries.images : Celtic knots : Re: Celtic knots Server Time22 May 2024 01:55:36 EDT (-0400)
 Re: Celtic knots
 From: BayashiPascal Date: 23 Dec 2021 19:45:00 Message:
```
{
"@context": "https://schema.org",
"@type": "DiscussionForumPosting",
"@id": "#web.61c517849e179f66c7449d78e0f8c582%40news.povray.org",
"dateCreated": "2021-12-24T00:45:00+00:00",
"datePublished": "2021-12-24T00:45:00+00:00",
"author": {
"@type": "Person",
"name": "BayashiPascal"
}
}
"Mediat" <med### [at] hotmailfr> wrote:
> I'll be glad to answer every question you have, basically I used the algorithm
> described on page 33 of https://www.maths.ed.ac.uk/~v1ranick/knots/celtic.pdf to
> build an array of "codes" (1= left, 2= up, 4=right, 8= down) each code + (i+j)%2
> (where i and j are the coordintes in the array),  gives the kind of brick and
> its orientation.
>
> for instance the array of the lower left knot is :
>
> 3 2 2 2 2 6
> 1 0 0 0 4 5
> 1 0 0 0 4 5
> 5 1 0 0 0 4
> 5 1 0 0 0 4
> 9 8 8 8 8 12
>
> Do not hesitate to ask ...

Hi Mediat,
Thanks for the link. Knot theory is not my cup of tea but that looks an
interesting read. I keep it for reference and hope to have time later to dive
into it.
The algorithm on p.33 is a nice one: simple and efficient ! However I can't see
if the authors also give instructions on how to place the barriers at the
beginning of the algorithm (I confess I haven't spent much time looking for it).
How have you done yourself ? Do you set them manually ?
Regards,
Pascal
```