POV-Ray : Newsgroups : povray.binaries.images : Behavior of bounded_by : Re: Behavior of bounded_by Server Time
15 Aug 2022 17:36:45 EDT (-0400)
  Re: Behavior of bounded_by  
From: William F Pokorny
Date: 18 Apr 2022 09:59:20
Message: <625d6eb8$1@news.povray.org>
On 4/18/22 07:01, m@b wrote:
> I made this leaf spring using segments of a rounded tube.
> It looks fine when viewed straight-on but assumes a funny angle at the 
> ends when viewed from the side.
> What is going on?

I've not tested it, but try adding:

clipped_by { bounded_by }

after each bounded_by{} statement.

Or, as Cousin Ricky recently suggested, in place of manual bounding 
create each spring leaf as an intersection of a 'bounding box' with each 
rounded tube.

Bounding - whether added manually or automatically - is only used to 
determine whether the real 'ray -> shape/surface' intersection code for 
the basic shape is run(a). In other words, ray -> surface intersections 
'can be' outside the bounding.

Bill P.

(a) - Yes, with manual bounding you can intentionally set up visual 
effects depending on how rays interact with the bounded_by shape(s). For 
example, the bounded_by shape(s) need not surround the actual 
shape/surface at all(b).

(b) - In official releases, manually playing with bounding is limited as 
there is code which prevents users from making bounding smaller by 
volume... In the povr fork that code is completely gone - IIRC. I think 
it wrong for POV-Ray to secretly ignore user bounding (some auto 
bounding too IIRC) based on a 'bounding volume can never be smaller than 
what already exists' test. Yes, users might screw things up more often - 
let 'em.

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