POV-Ray : Newsgroups : povray.text.scene-files : Tangents between circles : Re: Tangents between circles Server Time
24 Oct 2021 02:48:23 EDT (-0400)
  Re: Tangents between circles  
From: jr
Date: 26 Dec 2019 19:55:00
Message: <web.5e05550e1b345bf58c662f470@news.povray.org>

sorry for the delay, not forgotten, just occupied with fussing over a new
machine.  :-)  plus RL stuff.

"Bald Eagle" <cre### [at] netscapenet> wrote:
> Current full WIP for your perusal.
> In all it's glorious chaos.

phew, and I'm floundering..  :-(  cannot see how you've arrived at the data in
'CircleArray' elements 6 + 8/9.

(part of the confusion is that calculations and representation are so
intertwined, like when you use a colour ([n][6]) to select a tangent.  and what
is special about the order of indices in 'TangentList'?)

ideally, I would like only to input, per circle, centre, radius, and
(counter)clockwise direction.  choice of tangents and which part of
circumference to draw should be derived.

for instance, say three small circles forming a "nice" triangle.  if all three
run clockwise, it should render a triangular shape with rounded corners, but if
they run counterclockwise the triangle should have cut-out corners (bit like a
jigsaw piece).  iiuc, "inner tangents" would come into play when the next
circle's direction is the opposite of the current.

well, that is the idea(l).  Q - can you provide guidance, please?

this is just for drawing prisms, getting an understanding, really; ignore
pulleys for now.

and one more question, a prism made using just two circles, will that be doable
(wrt comment above 'ArrayIsLinear')?


> I haven't worked much on this recently because I got sucked into hounding like a
> dozen people about info on SVD, and so far I haven't gotten much except annoyed
> and maybe a headache.    I think I do have some ideas - I just need to get some
> time to hammer out some test code, etc.   Somehow I always have insights when
> I'm trying to sleep, rather than when I'm in front of the keyboard.   :|


(the program working to satisfaction now, I take it)

regards, jr.

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