Hi Mark,

my little scene was meant as an illustration of a geometric problem -- nice
to see it evolve into something really useable. I suggest to supply the
"linewidth" as an additional parameter instead of a constant fraction of
Radius. If you decide to change this value, it's much easier to have POV-
Ray doing all the calculations instead of "re-inventing the wheel again and
again by hand-calculation". And you can't animate the "linewidth" when
this relationship is fixed. The calculations have to be done anyway,
there is almost no difference between using "0.1*Radius" and "Linewidth",
so give this parameter to POV-Ray and let it do the boring numerical work.
Having a "linewidth factor" parameter also would be possible; the actual
value for this parameter would be 0.1 to reproduce what you've done, but
can easily be changed at will.

Because the thin circles have become rings with some linewidth now, there
arises a new problem: What is a "true gothic" constellation?
Of course the outer border/circle of the rings must touch the triangle.
But how large should these rings be?
   1. The outer circles intersect at the triangle's midpoint
      This is the easiest case: outer circle is as before; some linewidth
      is added towards the circle's centers.
   2. The inner circles intersect at the triangle's midpoint
      I don't think this is looking good with a large linewidth, so
      the calculation isn't worth it.
   3. The "mid-circles" with radius=(inner_radius+outer_radius)/2 intersect
      at the triangle's midpoint.
      I suppose this will look "most gothic", but will require some
      calculation ... (maybe I'll do this).

You should also try to remove the inner parts of the rings by difference-ing
with a cylinder around Center, having a radius = Radius.

Next tasks :)
   - replace the torii by cylindrical rings (difference of a cylinder and a
     thinner, but slightly longer [to avois coincident surfaces] cylinder,
     the Thickness being a new parameter). You have to do a little calculation
     involving Linewidth (or LinewidthFactor or whatever), but then changing
     this Linewidth is no pain: no new hand-calculation is neccessary, POV-Ray
     does it all. I suggest to write a macro Ring ( Radius, Linewidth ) that
     "behaves" similar to torus { Minor, Major ... }, this makes it easy to
     change all torus{} objects to Ring objects. The trick of omitting the
     closing "}" of the object created by Ring will help (look at the end
     of the Trefoil macro where I used this trick).
   - create your *own* stone texture
   - arrange some trefoils, light source(s) and a camera to create a pleasing
     scene; perhaps add some bricks, columns, decorative elements, windows,
     floor tiles, stone carvings, stairs, roof tiles, ...
   - at least *try* to find a solution for "true gothic" case 3.


Sputnik

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