[Edu-sig] python satacad: class 6

Kirby Urner urnerk at qwest.net
Sun Feb 20 17:00:45 CET 2005


Arthur:

> More Klein -
> 
> """
> It has long been the custom in the schools as well as the university,
> first to study the plane and them, entirely separated from it, the 
> geometry of space. On this account space perception, which we possess 
> originally, is stunted. In contrast to this the 'fusionists' wish to treat

> the plane and space together, in order not to restrict our thinking 
> artificially to two dimensions.
> """
> 
> Bucky and Klein seem to be on the same page, here.
> 

Indeed, thanks for the ammo (WMI-style).  Could I bother you to decorate
that with more bibliographic tags (including page number), so I can use it
elsewhere as a formal citation?

Resonates with my "Beyond Flatland" meme, i.e. lets start with full blown
spatial geometry, as that's the world in which we live our everyday lives.
The plane (especially the infinitely extended infinitely thin one) is a
relative abstraction, a kind of ancient geek (greek) metaphysics.

That being said, it's fun to have a 2D Python vector class for painting
flatly in POV-Ray or VPython, with the camera aiming directly at the XY
canvas, offset from the origin by some -Z (in POV-ray, -Z is towards the
viewer).

My approach (I think pretty standard) is to keep the vectors innocent of
POV-Ray, VRML or any output description.  Instead, have a "writer" class
that takes vectors as args, and writes accordingly (e.g. in VRML2).  Best
for the user is if the various writers share a lot of the same API, i.e. for
an edge in space, you want 2 vectors (the endpoints), and for a polygon, you
want the vertices going around in a list.  Euler's V,F,E cover the basics.

In my rbf.py, I made entire polyhedra subject to operator overloading, i.e.
if you go icosa * 2, it doubles in size (edgewise = an 8-folding in volume).
Or add a vector to it, and it translates.  I called it rbf.py after Fuller
and, true to form, set the CCP tetrahedron to volume 1 (makes for some nice
numbers in the others).

BTW, I submitted a proposal to OSCON aimed at making Fuller-FOSS links more
explicit, with a focus on Elastic Interval Geometry (Java big), Python in
the classroom (ala some of my experiments, various listservs), and a more
general push to open source global geospatial data (GIS), with reference to
Fuller's map (e.g. URL: http://themutemap.3d.openmute.org/modules/news/ ).  

However, based on feedback to date, I'm not especially hopeful this'll fly.
People may not be ready for it.  Oh well, there's always 2006.  I haven't
given up though.

Kirby

PS:  got an email from Tim this morning -- you may recall his blog for Fr
Bob, based on Pyblosxom with a lot of added features he wrote (including
basing it in Apache's mod_python) -- and these days he's getting into
Twisted, writing new IM infrastructure based on XML-RPC.  An 8th grader you
may recall.  Pretty impressive.





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