POV-Ray : Newsgroups : povray.binaries.images : Mesh2 Tools : Re: Mesh2 Tools Server Time
26 Sep 2022 09:04:38 EDT (-0400)
  Re: Mesh2 Tools  
From: Chris R
Date: 30 Jun 2022 14:55:00
Message: <web.62bdf099e9de8f10833fbc6f5cc1b6e@news.povray.org>
"Bald Eagle" <cre### [at] netscapenet> wrote:
> "Chris R" <car### [at] comcastnet> wrote:
>
> > > > I'd also
> > > > like to work on some transformations that could "wrinkle" the paper in
> > > > interesting ways as well.
>
> Certainly you could experiment with applying some of the native pattern
> perturbations like crackle or ... wrinkles.
>
> > I added a primitive "folding" capability to the code.  Right now it really only
> > works for one fold at a time in a given region.  I need to play around with it
> > so you can fold already folded regions.
> >
> > As you can see, the smaller the bending radius, the more points you need in the
> > mesh2 grid to avoid jagged edges along the fold.  I need to explore a more
> > efficient representation of the mesh and some code for sub-dividing the faces in
> > just those regions to avoid having a million faces in a single sheet of paper.
>
> I see where you're going with this, and it is indeed challenging.
>
> Perhaps you could define your sheet in terms of bezier patches.
> Then you could determine what patches are crossed by folds, and subdivide those
> patches to give more localized control if you have multiple folds.
>
> I think some of this may be headed straight for NURBS territory.
>
> I also recall seeing a lot of interesting computer graphics origami work that I
> just didn't have the time or energy to dive into.  That might be the way to go
> since the heavy lifting has already been done.
>
> https://langorigami.com/article/computational-origami/
>
> https://graphics.stanford.edu/~niloy/research/folding/paper_docs/folding_sig_08.pdf
>
> https://news.mit.edu/2017/algorithm-origami-patterns-any-3-D-structure-0622
> https://origami.c.u-tokyo.ac.jp/~tachi/software/
>
> http://masc.cs.gmu.edu/wiki/Origami
>
> https://dam-prod.media.mit.edu/x/files/thesis/2013/ysterman-ms.pdf
>
> .... and it goes on and on

With some minor tweaks I got some rudimentary folding of folds to work, but you
still have to deal with the resolution of the faces.

Thanks for the links to the computational origami papers.  That looks exactly
like the kind of rabbit hole I could find myself diving into for weeks on end.
:-)

For now, with the addition of the noise generation functions I probably have
enough to work on the scene.  If I can get the code cleaned up enough afterwards
I'll post it for any Java-heads who would be interested.

-- Chris R.


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