On 9/21/25 13:44, jr wrote:
> v confusing.  intervals (media) is a numeric value, your sor{} ones are string
> values.  how do those 5-char strings relate to the 8-element/point arrays ?

Documentation needs to be created. :-) A quick answer is that the number 
of spline-segments for the sor{} is always 3 less than the number of 
points specified. The length of the boolean bit string for control over 
all spline-segments is therefore (8-3).

For the lathe, the bit string length will differ depending upon the 
spline type. The same would be true for the sphere_sweep should the 
'intervals' feature be implemented there.

> on topic "sor{}" - is it "hollow" or "solid" as suggested ?  (I have an email
> thread "stalled" on this question :-))
One of my all time favorite streaming series is a show called "Patriot" 
on Amazon's Prime Video service.

https://en.wikipedia.org/wiki/Patriot_(TV_series)

On seeing questions, I often hear Michael Dorman's character saying 
"It's never that simple."

Depends on stuff - and for the keyword 'hollow' there is a pile of stuff 
I know, I don't know. I've never done a deep dive on how the setting 
cascades throughout the code. There is some weirdness with how it works 
and, IIRC, Alain pointed out one of those in the last year or two for 
some situation where adding 'hollow' magically fixed things.

The keyword 'hollow' means something closer to "You can stick media in 
this object" - except where it doesn't.

For the concept of solid, it mostly means the shape has a defined inside 
test in POV-Ray. That inside test can be kinda, arbitrarily, there at 
times - as is  the case with disc{}s, for example. Further, solid(as 
defined inside), doesn't necessarily mean closed-solid or 
surface-bounded-volume, which is often the stricter requirement for 
features like media and interior fading to work correctly.

With respect to Bill W's suggestion that the sor acronym assignment 
/alignment be changed to "solid of revolution", it just hits me as 
wrong. Perhaps this only due what I was exposed to over time. To me, 
when someone says "solid of revolution", it is the 3D volume a 3D object 
(a more mechanical thingy) requires when fully rotated about one more 
axes(*).

(*) - It would be an interesting way to define shapes in POV-Ray, if we 
work out how to do it(**).

(**) - I've wondered occasionally about adding an f_reuleaux_prism() 
inbuilt function and/or shape. The rotation of the defining triangle's 
center around a circle produces a nice, beveled "solid of revolution."

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