POV-Ray : Newsgroups : povray.text.scene-files : Tangents between circles : Re: Tangents between circles Server Time
21 Sep 2021 12:22:18 EDT (-0400)
  Re: Tangents between circles  
From: jr
Date: 17 Nov 2019 21:05:00
Message: <web.5dd1fb141b345bf5feeb22ff0@news.povray.org>
hi,

"Bald Eagle" <cre### [at] netscapenet> wrote:
> "jr" <cre### [at] gmailcom> wrote:
>
> Right-o.   I just got a quick demo scene posted before it dropped off the
> back-burner.
>
> > for the 'pulleys', in addition to centre + radius, having a texture would be
> > cool.  either as a "parallel" array, or perhaps using the new mixed array type.
> > now wondering how one could prepare for/support animation.
>
> Well there's no reason that can't be appended to the scene.
> Just make a cylinder or disc right below the circle array.
> Or a separate texture array that will use the current loop value in the arc/line
> plotting section.
>
> > if a start and end point get specified, that would get a "cable", while no
> > points would be a "belt", ie closed.  either way, the belt/cable goes around a
> > pulley either clockwise or counter (a boolean), so could be represented as an
> > array of floats for automatic "routing", 'N.0' for clockwise and 'N.1' for the
> > reverse, where N is the pulley array index.
>
> There are two portions of the post-calculation section.   one to make the
> bezier-arcs, one to make all 4 (if they exist) tangents.
> I have oh-so much of that in the developmental "full" version.   The logic and
> flags and texturing is bewildering, thus, the cut-down version.
> See the original developmental renders with the colored lines, arcs, and the
> color coded oriented/Boolean directional final belt path.

won't look at the code too closely for now.  just .. speculating.  :-)

> > anyway.  will be happy to do testing and help document, and what other (small)
> > help I can give.
>
> I'd say that the best help at the moment might be to just look it over and do a
> parallel implementation, starting from what I posted.   That would give me new
> ideas for how to process the data, and other things with what to do with the
> results that I might not have thought of yet.

will do this, sometime nearer weekend.  sorry.

> Also, asking any questions you may have about specific bits of the code would
> help me document it, and in the process re-read and re-think what I've already
> done.
>
> Certainly I'd love to work out the logic of animating it, and doing something
> like a toothed belt or chain to run along gears or sprockets.

just support for the pulley rotation should do, I think.

> I haven't done much pathological case testing, because it's already a miracle
> that it even works at all.

will play with it etc.  cheers.


regards, jr.


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