"Tor Olav Kristensen" <tor### [at] TOBEREMOVEDgmailcom> wrote:

> Hi Bill
>
> That's a very interesting vase.

There's a lot of interesting items that they've discovered, and the ridiculous
level of accuracy and tight tolerances in such a hard and heterogeneous material
raises a LOT of questions.

> I just wrote a little Python script using numpy and numpy-stl to
> extract the 473864 unique vertices from the STL file and store them
> and the corresponding face indices in arrays in a POV-Ray .inc file.
> (The number of non unique vertices in the STL file is 2811429.)

Hmmm.   Very nice.
1. how large is your .inc file?
2. can you make that into a mesh2 {} ?   Will that make the file size smaller?
3. would it be possible without undue work to number (with comments) the unique
vertices and correlate the redundant vertices with the ones in actual use?
(listing them all at the end of the file in a large en-bloc comment and marking
them with the numbered vertex that they are a duplicate of)

I only bring these things up because if you did such a thing and posted that
file here on the POV-Ray forums, it might generate some new traffic and
potentially bring in some new users to discover what POV-Ray has to offer.

> Here's a rendering with triangles, cylinders and spheres made with
> data from that .inc file, showing the details around one of the
> handles on the vase.

That is certainly a LOT of triangles.

I don't know if you've looked at the article by Mark Qvist posted here:
https://unsigned.io/granite-artifact/


RTI?
https://twitter.com/mariusderomanu3

I've been curious about the vertex coordinates that Mark is using for his
diagrams, and what sorts of tools would be best suited to replicating or
obtaining a truer-to-reality analysis of the surface features.   Maybe some kind
of least-squares best fit, or some way of determining which points a line would
be "tangent" to on both the rim and lug handle.


There really are a lot of different dimensions and geometric relationships to
investigate.   I'm really hoping that they are able to obtain a complete mesh of
the vessel as well as doing some microscopic / spectroscopic analyses of the
surface to see if any residues of the work-holding fixture or tooling remain
embedded in the surface.

Thanks for taking a look and processing all those vertices.  I'm curious what
your thoughts are about the vase in general, as well as what sorts of analyses
you think might be interesting to perform, and what sorts of POV-Ray fun could
be had with it.

- BW

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