




Date: Mon, 28 Mar 94 12:13:24 AST
From: Brian Ewins <gapv64@udcf.gla.ac.uk>
Subject: Re: 80% (long) (origo)

Hi,
        just until there's a name, I'm going to keep the
'80%' title on any posts converning the origami script language.
This letter's about how it _might_ be implemented, I'm trying
to make things more concrete so that problems can be discussed.

Where I use stuff that looks like code, I'm going to write it
similarly to PostScript. This isn't because I think PostScript
would be a good language to write the program in: it has some
particularly bad features for this purpose anyway. However,
postfix, stack-based, threaded interpretive languages (TIL) are
much easier to write (I mean from scratch, not using YACC).
Basically, all objects when seen, are pushed onto a stack of
'things', the last object in is the first out, and functions are
just sequences of commands that expect a certain pattern of things
to be on the stack. eg.
1 2 add (puts 3 on the stack; it expects to see 2 numbers there
when add is called. That's just to explain what gives to those who
havent seen this before.)

Ok. Basically the problem (possibly) breaks down into 4 parts:
1. Input syntax
2. Internal format/manipulation
3. Output format (drawing)
4. Save format

I'll go through these one at a time to point out how we might proceed,
and what the problems might be.

1) Input. taking a top down approach to the design we see this:
        a) every model is a complex fold.
        b) every complex fold is a collection of simultaneous or
               sequential simple folds. We then invent the command
               'fold' which acts on a comma separated list of
               fold descriptions (descriptions of simple folds)
               eg. f1,f2,f3 fold f4 fold
               Where all folds up to the next 'fold' command are
               done simultaneously. f1,f2,f3 might, for instance
               be the parts of a squash fold, and f4 might be
               a valley fold.
               (the commas might not seem necessary in a TIL
        c) There are many ways of describing simple (valley/mountain)
               folds. Obviously these are equivalent, (and valley
               and mountain folds are pretty much the same too)
               so we just need 'filters' which convert fold
               descriptions to some canonical (internal) form,
               from the following:
               point -> point, edge -> edge,
               point -> edge (with a fixed point)
               angle n-section (bisection,trisection, or an actual angle)
               2 points -> 2 edges (I don't know if this ever
                     gets used)
        d) ok, so we need some way of describing points and lines
               (required by the last section). We'd also like if
               possible to hide implementation details from the
               user. One good way of doing this is to name points
               (or lines, or groups of points). Note 'name' not number.
               Half way through a 100 fold diagram you are likely
               to have forgotten what point 13 was, but a name like
               'head' 'beak' or 'nose' is easier to name.
               We take it as granted that the original points (of,
               usually, a square) are labelled (say,A,B,C,D) and then
               label all other points by reference. e.g.
               (A) (B)   [2 points: is the line A->B ]
               (A) (B) 0.5 section [ is the midpoint of AB ]
               (A) (B) midpoint [its likely we'll want macros for useful stuff]
               (A) (C) (B) (D) intersection [ labelling corners of a square
               clockwise, this would give the centre point ]
               ... note that this last leaves the _internal_ rep of the
               centre point on the stack. We could give it a name, like this:
               (A) (C) (B) (D) intersection (centre) name
               or use it directly, eg here I begin a blintz-fold:
               (A) (C) (B) (D) intersection (D) exch pointpoint valley fold
               [ exch exchanges top two things on stack, pointpoint
               and valley are 'filters' as described above]

At this point, we have got the beginnings of a nearly workable syntax.
However, it is a syntax for doing simple things; I found it hard to
express the meaning I wanted to make a preliminary fold using this
( by folding along a diagonal and two squash folds, rather than
collapsing a prefolded version as is usual )
and I don't know how it could be used meaningfully to (eg) squash
fold more than one layer together. Note that I've stayed within the
80% and found a problem, since squash folding is used to make all of
the simple bases (collapsing is even harder to describe!)
        We'd also like to have some 'symmetry' notation in the syntax,
since we'll often want to say 'repeat behind', etc. However, I feel
that this falls outside a first attempt, since anything that could be
described this way could just be described by repeating commands.
        Anyway, I could add more to this section, but I'll leave it
here for now, since greater detail of what I did on this line would
impede general discussion.

2. Internal representation.
In the syntax described above, points _appeared_ at the surface.
(actually pointers to points). More detail is required to express
the layering of polygons of paper. Here we should be thinking of
asking Robert Lang if we could cannibalise his code - after all, it
_works_. It's a bit difficult to work on without knowing exactly
what is needed in the display section (full 3d points or layered
flat sections). A minimum requirement is the ability to determine
internally if a set of simultaneous folds (in the fold command above)
produces a flat vertex (I forget the name of the theorem, it's
descibed in Origami for the Connoisseur), since our 80% will
almost certainly be restricted to flat models.

3. Display. It's probable that it will be decided to proceed
with displaying polygons from back to front, rather than full,
raytraced 3d. However, it should be pointed out that problems
arise with this even in pureland origami.
Take a strip of paper and fold it over at 90 degrees to its axis.
repeat another 2 times, always folding 'up' .The result looks like:

/_____| \
| |   | |
| | __|_|
|A| Z___/

The problem is what we do with end 'Z'. If it goes _over_ A then
everythings fine; A is under Z, and under 2 other strips which are
under Z. if Z goes _under_ A then A is over Z but under a strip
which is under a strip which is under Z , so if we just printed
polygons one after the other we would have a problem. An algorithm
which wouldn't loop infinitely would probably place Z (wrongly) on top.

This isn't just an abstract problem; I can think of two models off the
top of my head which are like this (Andrew Anselmo's dollar bill
dollar, is, however, the only one I can think of in the '80%' category)
...probably many more would have this problem. The upshot is,
we probably need full raytracing even on the simplest models.

Another point to consider is something which isn't a problem (but could
be percieved as one). Models which become 3d temporarily can still
be diagrammed using this type of program even in its simplest form
by making the folds during the 3d stage 'invisibly', jumping ahead
a few stages by folds that would be difficult to really do. The original
picture for the last stage before the '3d' part can be output in the
format for some drawing program and adjusted, making the process easier.

Also: I did not cover the commands to flip paper, magnify, rotate models
in the syntax section. That was because they are actually irrelevant to
the program: flipping paper just reverses the meaning of mountain and
valley, it doesn't change what the model looks like internally. There
should be commands for doing this stuff, however, and adding notation;
It's just that it's not the hard part of the program, and we should
be looking for the wood.

4. Save format. This might seem a little odd, since we have already
covered input and output; but I assumed at the start of the input
section that we would have  a labelled square, armed and ready so to
speak, without saying where this came from. I see no problem with
supporting odd shapes of paper from the _start_, if there is some way
of getting the program to read a file containing labelling
instructions for pre-folded bases, money shapes, etc. After all,
the program has to be able to support general polygons later on
(once we have begun folding). This depends strongly on the internal
representation.

Finally, implementation: there should be at least 2: a WYSIWIG
logo-like interpreter: instead of showing a few stages of any
model , it should show changes to the model as you type
them. (If the implementation was a TIL as described here it would
also be a good idea if the stack was visible in a window. )
That's the designer end. At the viewer end, there should be
a program to convert output to the format of some viewer
(PostScript? or 3d-POV-ray format? doesnt matter)... intended
to support a minimum hardware (you have a printer, or
a graphics card better than a Hercules, is the minimum for
using GS; this would probably do.)

        Anyway, sorry to ramble on so.
               I'd just like to generate comment.

                     Baz.





Date: Mon, 28 Mar 94 12:27:25 AST
From: tjj@rolf.helsinki.fi (Timo Jokitalo)
Subject: Re: Newsgroup echo

> Okay, I talked myself out of it, let's try for rec.crafts.paper.origami.

Oops, I hope I didn't cause that! :-)

I have also observed that there is no mailing list for paper crafts. Perhaps
the reason is that there is not enough of an audience? (Hmm... seems
implausible.) My original idea was that perhaps just one general papercraft
group would be enough, but now that I think more carefully I begin to see
that it would of course be better to have a hierarchy. But if we end up
having just one group, would it be too noisy an idea to set the charter so that
other crafts could be included? And would rec.crafts.origami be a bad name
in that case?

        Timo





Date: Mon, 28 Mar 94 12:39:28 AST
From: Bruce Stephens <bruce@liverpool.ac.uk>
Subject: Re: Newsgroup echo

> I'd love to see rec.crafts.paper, too, because I'm also interested in
> things like paper mache, rocketry, papermaking, and other crafts that
> are related.  But I don't see any mailing lists dedicated to any of
> those but rocketry, which already _has_ a newsgroup (in rec.models.
> rocketry), so I don't see a defensible reason to call for the second
> hierarchy level yet.  If news.groups feels differently, we'll see a lot
> of calls to add that hierarchy, I guess.  Also contrariwise, I suppose.
> Okay, I talked myself out of it, let's try for rec.crafts.paper.origami.
> But be prepared to pull back to rec.crafts.origami if it seems the senti-
> ment is against it.

I agree with your comments.  It's just that I watched the recent RFD on
rec.crafts.origami, and I feel that rec.crafts.paper would have got
through.  To be sure, it might have proved unsatisfactory for
discussing origami, but I don't think so.  My guess is that most people
interested in paper are interested in origami, and vice versa, to an
extent at least.  I think we should try rec.crafts.paper, and split if
necessary.  (Or, if this is possible, just gateway the mailing list

> Larry Smith
> larrys@alpha.zk3.dec.com

Bruce                   Institute of Advanced Scientific Computation
bruce@liverpool.ac.uk   University of Liverpool





Date: Mon, 28 Mar 94 12:50:51 AST
From: Brian Ewins <gapv64@udcf.gla.ac.uk>
Subject: Re: Newsgroup echo

rec.crafts.origami can just be used as a title;
Those looking for other crafts will probably
check it out, we could have a charter covering other
crafts too. If _later_on_ demand makes it necessary
to change the name, we could do that.

        Baz.





Date: Mon, 28 Mar 94 13:54:32 AST
From: bartlone@ct.med.ge.com (Mike Bartolone 5-4266)
Subject: Re: Newsgroup echo

Posting to news.answers is not quite as easy as Larry makes it sound.
I believe that this newsgroup is moderated and they have some very
strict guidlines. like these...

The FAQ's need to be 1) in the right format.
                 and 2) from a usenet newsgroup

They do not allow mailing list FAQ's to be posted. Also, the FAQ's posted are
posted from another archive. Your FAQ(s) must conform to the proper format for
the mail server that handles them...





Date: Mon, 28 Mar 94 14:16:03 AST
From: larrys@zk3.dec.com
Subject: Re: Newsgroup echo

>My original idea was that perhaps just one general papercraft
>group would be enough, but now that I think more carefully I begin to see
>that it would of course be better to have a hierarchy. But if we end up
>having just one group, would it be too noisy an idea to set the charter so that
>other crafts could be included?

Aaaahhhh, I catch your drift now.  Hmmmmmmmm - if we wanted to end up with
a hierarchy of paper-related newsgroups but only wished to create a generic
papercraft group from which they would split later, then that group would
actually be named rec.crafts.paper.misc.  Perhaps:

NEWSGROUP rec.crafts.paper.misc unmoderated

This newsgroup is dedicated to discussion of all aspects of paper crafts
including, but not limited to, origami, paper airplanes, cut'n'assemble,
and paper mache.

r.c.p.m encourages the use of header markers for the convenience of those
using modern newsreaders.  The topics and their markers are:

C&A: cut and assemble
PM:  paper mache
ORI: origami

...please everyone feel free to snarf this into a reply and add whatever
other paper crafts might go in.  I think this might be a valid idea.
Certainly, I would vote for it.

Larry Smith
larrys@alpha.zk3.dec.com





Date: Mon, 28 Mar 94 14:54:27 AST
From: LHODSDON@smith.smith.edu
Subject: Re: not Origami

Since Palm Sunday just passes, you might like to know that those Swedish
stars are also called Easter Stars and can be made from palm fronds.
(You need four pieces of about the same width, usually one frond can
be cut into two of the four pieces).  I also make them out of Christmas
ribbon (it has to be about the same color on both sides, because both
sides show in the finished model.) and use them as tree decorations and
package decorations.  They can be left unfinished so that one side is
flat, allowing them to be placed on packages and the like.  Very small
ones can be made out of narrow strapping tape of the type used to hold
shipped boxes -- these are waterproof, whatever that's worth.  I don't
know where instructions are printed (though I know they are somewhere)
they are definitely worth finding--if you don't mind the impurity of
the origami!!
Lisa Hodsdon
lhosdon@smith.smith.edu





Date: Mon, 28 Mar 94 16:18:36 AST
From: Soylent Green <rhudson@yorkcol.edu>
Subject: Re: Newsgroup echo

Mixing Origami with other papercrafts is like mixing a child  with rabid
monkeys.  Sure, nothing MIGHT happen, but there's a good chance one of the two
parties involved will change.  Origami alone is the purest form, more or less,
of the papercrafts.  Nothing bothers me more than seeing a crafts book with
great looking origami photographs, and discovering that, unlike Montroll's
fantastic models, the spiders in the picture was made with eleven small cuts
and "just a spot of glue"  Usually, these books MAY have waterbomb diagrams,
but they typically show a spot of Scotch used somewhere therein.

Rob





Date: Mon, 28 Mar 94 16:32:00 AST
From: Soylent Green <rhudson@yorkcol.edu>
Subject: relative impurity

Lisa:

They're only really impure in that you cut the final ends out.  I suppose if
you were really dextrous, you could find the EXACT length of the fronds or
strips to use, then it would be pure modular origami.

Rob





Date: Mon, 28 Mar 94 16:53:25 AST
From: larrys@zk3.dec.com
Subject: Re: Newsgroup echo

>Mixing Origami with other papercrafts is like mixing a child  with rabid
>monkeys.  Sure, nothing MIGHT happen, but there's a good chance one of the two
>parties involved will change.

I don't see the point of this.  A newsgroup that carries traffic for a
range of subjects may have a fair amount of crossover - as when, for
example, a D&D players gets a good idea from a GURPS post in rec.games.
frp.misc - but that doesn't mean the games are going to merge.  Cross-
over is a _good_ thing, not a bad, and it doesn't mean something will
"change".  Just set up your kill file to screen anything lacking ORI
in the subject line.  Or stick with the mailing list, the list would
not be gated from a generic papercraft group, though the listserver
might still _forward_ posts to such a group.

Like it or not, cut'n'assemble and paper mache are our cousins.  We
need to stick together and form a united front against those people
who use - shudder - "plastic".  Ohhhh!  I said the "p"-word!   :)

Don't let's let our prejudices keep us from reaching a wider audience.
It's quite as likely we'll find more purists out there than crossover
types.  And a strong origami presence - all but guaranteed by the fact
that it _is_ we who are calling for the group - will be more than enough

Larry Smith
larrys@alpha.zk3.dec.com





Date: Mon, 28 Mar 94 17:04:29 AST
From: Marc Hache <Marc_Hache@MBnet.MB.CA>
Subject: Looking for Heart Locket and Grand Piano

Hi,

Anyone know whwre I can find:

Heart Locket - Gay Merrill Gross
Grand Piano - Patricia Crawford

Thanks,
Marc Hache





Date: Mon, 28 Mar 94 19:21:26 AST
From: AHELM@utxvms.cc.utexas.edu
Subject: connoiseur

>Well, ORIGAMI CONNISEUR is very hard.  I'm still at the beginning.  I just
>finished the menko.  Even when I figureout the fold it is ugly because
>something happens to my accuracy although I have been very careful.  I guess
>it just takes practice.

Good luck to you Linda, I too have started on CONNOISEUR, since I have a
it on limited loan from another library.  I jumped right in on the rose and
the sea shell.  The rose was a beautiful challenge, IMHO, but I'm having fun
with all of them.  The space shuttle is pretty easy to do.  And if you are into
more of the geometric designs, I hope you get your hands on some Tomoko Fuse
books soon.

Cheers,
Anthony Helm





Date: Mon, 28 Mar 94 19:52:06 AST
From: Soylent Green <rhudson@yorkcol.edu>
Subject: Paper Prejudice:Racism Reverse Fold

Well, as long as the origami group is kept relatively isolated.. I shudder to
think what might happen with an influx of the old "well, I couldn't fold it, so
I just trimmed a little..." types.

Sorry, I'm hopelessly set in my ways for such a bitter young man,

Fold or Die!
Rob





Date: Mon, 28 Mar 94 21:58:19 AST
From: "T.K. Lam" <mud05@cc.keele.ac.uk>
Subject: Re: Looking for Heart Locket and Grand Piano

> Hi,
>
> Anyone know whwre I can find:
>
> Heart Locket - Gay Merrill Gross
> Grand Piano - Patricia Crawford
  ^^^^^^^^^^^

  This ( Baby Grand ?) in Robert Harbin's _Origami_4_ ( There are some other
splendid 'technology' folds there from the mid '70s.  Look at Dave Brill's
_Flip_top_ and the Elias models )

>
> Thanks,
> Marc Hache





Date: Mon, 28 Mar 94 22:45:44 AST
From: "Robin Fisher (DSMD)" <rfisher@Census.GOV>
Subject: Re: connoiseur

Hi, I'm new.  I was moved to respond to the mention of this book and
Fuse's.  I think the shells in _connoisuer_ are some of my favorite
peices.  Ihave trouble with the lidded cub box at the beginning where you
do the "division into five equal parts," though.

I just purchased Fuse's book _Unit Origami_.  I guess I'm going to have
to go out and get a lot of paper.  This will be my first foray into the
world of modular origami besides the Sonobe cube in _connoiseur_.  I'm
half excited, half intimidated.

Robin





Date: Tue, 29 Mar 94 00:07:13 AST
From: LONNIER@nickel.mincom.oz.au
Subject: Origami 4 - Robert Harbin

Does anyone know if Robert Harbin's book 'Origami 4' is going to be
rereleased along with his other books. I have volumes 1-3 but not 4.
Please let me know if anyone has any idea where I might get a copy.





Date: Tue, 29 Mar 94 03:57:27 AST
From: "M.J.van.Gelder" <M.J.van.Gelder@rc.rug.nl>
Subject: Origami Language (was PAPER) (origo)

On the choice of the name of the language: we could take the Japanese version
of Paper Folding Language: OriGamiGo. In this Ori means bend/fold, Gami means
paper and Go means language.

For my ORIDRAW/OriToPs program package I use a language of drawing commands
especially adpted to Origami. So it knows of valley and mountain folds. And
it follows the international drawing standard for Origami.
It is NOT a language to describe folding, but a language to diagram the
folds. And it short. ORIDRAW can draw the diagrams on screen and OriToPs
generates the PS file. As an example I include the Waterbomb base in this
language:

Waterbomb base
Traditional
940328
n 1
lg 4
tb Make mountain and valley creases and then collapse as indicated
r 0 0  16 16   v 8 0  8 16   vb 0 8  16 8
im 8
vd 0 0  16 16   a 0 16  0 0  -0.5   a 0 8  8 0  0.5
n 2
tb Waterbomb base finished
fs  v 0 -0.4  16 -0.4  8 8  fdd
im 8
fs  v 0 -0.4 7.9 -0.2  8 8  fwd
fs  v 0 0    7.9 -0.2  8 8  fed
imn
fs  v 0 0  16 0  8 8   fwd

The accompanying PS file is in the archives in directory models. Also that
file is fairly small (5.5 KB).
Perhaps you don't understand this language at first sight. The documentation
and the programs are in the archives too (directory programs/oridraw).

But I think it isa worth while to try and create a real OriGamiGo.

Maarten van Gelder                   M.J.van.Gelder@RC.RUG.NL
Lichtboei 210                        Rekencentrum Rijksuniversiteit RuG
9732 JK  Groningen                   Groningen
Holland                              Holland





Date: Tue, 29 Mar 94 04:06:44 AST
From: "M.J.van.Gelder" <M.J.van.Gelder@rc.rug.nl>
Subject: Re: Newsgroup echo

Someone complained about the flood of messages he had to wade through. That
flood just came in the last few days. In the past we had ups and downs on
this list. You can see that in the archives. I collect about 60 KB per file
and somtimes it took three months to fill one file. But right now it took
only two days (75 messages)!

About the newsgroup:
If a newsgroup is started and the messages are send over to and from this
group, don't we get flooded by all the stuff from the newsgroup? I don't like
that. So I am not sure about coupling the two together.

I think that using the subject line in your message is neccesary and may help
other members of this list to skip over messages they don't like.

Maarten van Gelder                   M.J.van.Gelder@RC.RUG.NL
Lichtboei 210                        Rekencentrum Rijksuniversiteit RuG
9732 JK  Groningen                   Groningen
Holland                              Holland





Date: Tue, 29 Mar 94 08:58:39 AST
From: Brian Ewins <gapv64@udcf.gla.ac.uk>
Subject: Re: PS files (PostScript)

Can you compress bitmaps?

...well yes and no.  Level 2 PS supports a compressed bitmap format which is
essentially GIF, and most PS printers these days (and GS) understand level2. 
However, you need to get the bitmap compressed first.  Since the usual way to
output PS is to send it to a file via the printer driver, the driver has to
know level 2.  And herein lies the problem.  Microsoft (and Apple) are
currently not providing much in the way of support for level 2.  Until
there's a tool for converting level 1 to level 2, or Bill Gates gets whats
coming to him, we're stuck with the usual huge bitmaps. 

        Baz.





Date: Tue, 29 Mar 94 08:15:00 AST
From: tjj@rolf.helsinki.fi (Timo Jokitalo)
Subject: Re: 80% (long) (origo)

>                centre point on the stack. We could give it a name, like this:
>                (A) (C) (B) (D) intersection (centre) name

How could we handle the naming of the new points created at the endpoints
of the new crease, and the intersections of it and previous creases? It
could be done of course like (to use your example)
(A) (C) (B) (D) intersection (centre) name
(A) (D) midpoint (E) name
(C) (D) midpoint (F) name
(centre) (D) exch pointpoint valley fold
but that seems cumbersome, and would require one to name the points
before the fold is made. Some 'automatic' way would be best, but at this
moment I have no ideas...

> However, it is a syntax for doing simple things; I found it hard to
> express the meaning I wanted to make a preliminary fold using this
> ( by folding along a diagonal and two squash folds, rather than
> collapsing a prefolded version as is usual )

Perhaps, if we wrote
 (A) (C) (B) (D) intersection (centre) name
 (A) (C) valley fold
Then,
 (centre) (B) valley
 (B) (C) midpoint (centre) mountain
 (D) (C) midpoint (centre) valley
 fold
would seem enough to make the fold unique. But I can't see how to turn it into
a meaningful internal expression... And here also having a name for the
two midpoints would be a help.

> and I don't know how it could be used meaningfully to (eg) squash
> fold more than one layer together.

Again, I think that might be overcome by naming the reference points in
each layer separately. (Or am I not thinking carefully enough?)

> 3. Display. It's probable that it will be decided to proceed
> with displaying polygons from back to front, rather than full,
> raytraced 3d.

It seems to me that full ray-tracing would require a lot of computing.
Probably situations like your problematic example could be handled by
the program being able to figure out how to split the polygon Z into two
parts (like having two sections of paper without a crease in between) which
could then be correctly displayed by just displaying everything in order
from back to front. It's not easy, I think, but probably a lot faster than
ray-tracing.

(We could then, after the program is otherwise complete, implement the
FEM (?) model for paper which I mentioned some weeks ago, from IEEE computer
graphics & applications, and use that and ray-tracing to build a realistic
'photograph' of the finished model!)

        Timo





Date: Tue, 29 Mar 94 09:18:45 AST
From: Brian Ewins <gapv64@udcf.gla.ac.uk>
Subject: Re: 80% (long) (origo)

tjj@rolf.helsinki.fi writes:
| >                (A) (C) (B) (D) intersection (centre) name
|
| How could we handle the naming of the new points created at the endpoints
| of the new crease, and the intersections of it and previous creases? It
| could be done of course like (to use your example)
| (A) (C) (B) (D) intersection (centre) name
| (A) (D) midpoint (E) name
| (C) (D) midpoint (F) name
| (centre) (D) exch pointpoint valley fold
| but that seems cumbersome, and would require one to name the points
| before the fold is made. Some 'automatic' way would be best, but at this
| moment I have no ideas...

You have hit the nail on the head here. There _is_ a
problem with naming points that 'appear'... to combat this, I was thinking
about the 'filter' for folds producing them always in the form of
the endpoints of their crease: eg
(A) (C) pointpoint valley
would produce (B) (D) on the stack, along with another number
indicating the direction of the fold (A->C or C->A, mountain or valley)
from the 4 possibilities. This produces the points wanted.
There is a slightly different solution for 'automatic naming'
which goes like this: we have variables, and when the program
sees '$i$' in a string, eg (A$i$) it replaces it with the value
of the variable eg (A1). I thought of this mainly in connection
with loops for doing 'repeat behind' and stuff like that.
| > However, it is a syntax for doing simple things; I found it hard to
| > express the meaning I wanted to make a preliminary fold using this
| > ( by folding along a diagonal and two squash folds, rather than
| > collapsing a prefolded version as is usual )
|
| Perhaps, if we wrote
|  (A) (C) (B) (D) intersection (centre) name
|  (A) (C) valley fold
| Then,
|  (centre) (B) valley
|  (B) (C) midpoint (centre) mountain
|  (D) (C) midpoint (centre) valley
|  fold
| would seem enough to make the fold unique. But I can't see how to turn it into
| a meaningful internal expression... And here also having a name for the
| two midpoints would be a help.
|
| > and I don't know how it could be used meaningfully to (eg) squash
| > fold more than one layer together.
|
| Again, I think that might be overcome by naming the reference points in
| each layer separately. (Or am I not thinking carefully enough?)
You're right. But the problem is the number of points that will
have to be labelled.
| > 3. Display. It's probable that it will be decided to proceed
| > with displaying polygons from back to front, rather than full,
| > raytraced 3d.
|
| It seems to me that full ray-tracing would require a lot of computing.
| Probably situations like your problematic example could be handled by
| the program being able to figure out how to split the polygon Z into two
| parts (like having two sections of paper without a crease in between) which
| could then be correctly displayed by just displaying everything in order
| from back to front. It's not easy, I think, but probably a lot faster than
| ray-tracing.
Actually, ray tracing by the simplest (scan line) algorithm is fairly
easy. It becomes difficult when we allow reflections, wierd light
sources, etc. You're right again about splitting into more polygons.
I thought of this when I was interested in doing my original program
(just a stack of non-overlapping polygons) but I became concerned that
the polygons would become too numerous to handle. I see now that it's
ok: you just split them at the display stage.
| (We could then, after the program is otherwise complete, implement the
| FEM (?) model for paper which I mentioned some weeks ago, from IEEE computer
| graphics & applications, and use that and ray-tracing to build a realistic
| 'photograph' of the finished model!)
|
|       Timo
                     Cheers,
                          Baz.





Date: Tue, 29 Mar 94 10:40:09 AST
From: larrys@zk3.dec.com
Subject: Re: Newsgroup echo

>If a newsgroup is started and the messages are send over to and from this
>group, don't we get flooded by all the stuff from the newsgroup? I don't like
>that. So I am not sure about coupling the two together.

Depends on how you gate it.  You _could_ just enter rec.crafts.paper.origami.
usenet@decwrl.dec.com in the current mailinglist and only gate the list to
the newsgroups.  Of course, any discussion one of those messages generates
will stay in the newsgroup, it won't be gated back.  Pluses and minuses
either way.

>I think that using the subject line in your message is neccesary and may help
>other members of this list to skip over messages they don't like.

No question.  It has helped some groups (r.a.tv.soaps, for example) to
document Subject: conventions in the charter and to periodically repost
the recommended markers.

Larry Smith
larrys@alpha.zk3.dec.com





Date: Tue, 29 Mar 94 11:05:16 AST
From: lau@desci.wharton.upenn.edu (Yan K. Lau)
Subject: Re: not Origami

Joseph Wu writes:

> The diagrams in _Lifestyle_Origami_ are atrocious. They make a few
> assumptions and skip many steps.

I disagree.  The diagrams in _Lifestyle_Origami_ are not atrocious.
That is a far too harsh characterization.  The missing steps in the star
is of the variety, repeat steps for the other three sides.  This is
readily apparent from looking at the diagrams.  I had no trouble
following the instructions this morning when I folded the star.

I have been able to fold even some of the more difficult models such as
the heart gift box and the chalice.  Moreover, I can not see how any of
the geometric modulars are difficult to follow though I haven't tried the
last one yet.  And, the simple models are just that.

Ansill's book takes a wider definition of origami.  There are napkin
folds and an origami cut pop-up.  Whether the star is origami is
debatable.  The cutting of the excess at the end is one problem.  It is
not modular origami because there are no units.

Ansill's other book, _Mythical_Beings_ is in general much more difficult.
I've have trouble folding the models in there.  I don't know if this is
due to poor diagrams or my own ineptitude though.

Yan.

          "I think we're both gonna make it *big*. I am very optimistic."
   )~  Yan K. Lau          lau@desci.wharton.upenn.edu          130.91.161.6
 ~/~   OPIM Department     The Wharton School     University of Pennsylvania
 /\    God/Goddess/All that is -- the source of love, light and inspiration!





Date: Tue, 29 Mar 94 10:52:48 AST
From: Soylent Green <rhudson@yorkcol.edu>
Subject: Origami 4

Can anyone provide a source for xeroxes of Origami 4?  I assume it's out of
print..

And to Rockwell Smith (sp?)... I'm working on your diagrams for Bunny Bill!
wil have them soon.. promise!

Rob





Date: Tue, 29 Mar 94 11:12:48 AST
From: lau@desci.wharton.upenn.edu (Yan K. Lau)
Subject: Perfect models.

In the new issue of the FOCA Newsletter, there is an interview with
Dr. Robert Lang.  Among the things he mentions are "perfect models",
models that he will not attempt because the definitive models has been
folded.  The two that he points out is Montroll's stegosaurus and
Kawasaki's rose.  I agree that these models are perfect.

I found the article very interesting reading.  There is also a good
discussion on the merits of foil, who uses it, who doesn't, why?

Yan.

          "I think we're both gonna make it *big*. I am very optimistic."
   )~  Yan K. Lau          lau@desci.wharton.upenn.edu          130.91.161.6
 ~/~   OPIM Department     The Wharton School     University of Pennsylvania
 /\    God/Goddess/All that is -- the source of love, light and inspiration!





Date: Tue, 29 Mar 94 11:45:58 AST
From: Erik Emmery Jones <kire@well.sf.ca.us>
Subject: Re: connoiseur

robin as far as the unit stuff goes thicker paper is accepatable for some of
it  if fing no shortage of "waste" golssy printed paper in various places.
some of my favorite unit peices are made from cut up rave flyers and old
calenders..as far as the division by five try try try again ;)
e.z. creasin.





Date: Tue, 29 Mar 94 13:27:47 AST
From: bartlone@ct.med.ge.com (Mike Bartolone 5-4266)
Subject: Re: Guidelines for posting to news.groups (newsgroup)

I also want to mention a few things about the news to e-mail gateway
discussion. The Bonsai mailing list has been operating on a bi-directional
news-to-mail gateway for about a year now. The total number of posts has
NOT increased dramatically, but it has increased some. Many of the
people who WERE subscribers to the mailing list have just moved over
to read the posts in the newsgroup. There were also a few people who moved
the other way...people who for one reason or another were having problems
reading "news".

Look carefully at Larry's post...there is a REQUIRED field called
"Newsgroups"...no newsgroup, no posting in *.answers groups...





Date: Tue, 29 Mar 94 14:20:36 AST
From: Joseph Wu <jwu@cs.ubc.ca>
Subject: Kawasaki's seashell [was: Re: What to Do with Origami]

On Thu, 24 Mar 1994 base00!jhc@codas.attmail.com wrote:

> Question for everyone:  Kawasaki shows a seashell with one instead of four
> openings, and blithely states that the model is "modified".  God, I hate that.
> I've tried, and have not come up with a way to do it.  Any answers???

The solution appears in two places that I know of:

Kasahara's _Origami:_El_Mundo_Nuevo_, and
Fuse's _Spirals_

Connoisseur "blithely states" that the modification is a simple one, but
it occurs early on in the folding method and is not easy to explain. It
also results in a significant decrease in the size of the final model, so
that starting with a 10-inch square results in a model that fits in a
3-inch cube.





Date: Tue, 29 Mar 94 14:37:44 AST
From: Joseph Wu <jwu@cs.ubc.ca>
Subject: Re: not Origami

And I disagree right back at you! 8) Ansill has made some good selections
in both of his books and has presented them well, with many colour photos.
However, I must still complain about his diagramming in general. He is
(and I can relate to this) just plain lazy. He skips steps. He reorients
the model without letting the reader know. He does not clearly label
repeated steps, simply assuming that the reader will understand.
Perhaps...I certainly had little trouble with most of the models, but
that's no excuse for sloppiness. The only model in his two books that I've
been unable to fold is Robert Lang's "Cerberus". Ansill gets to esoteric
in his diagramming even for me at that point. And I still maintain that,
while I understood what he meant, Ansill was at his worst in his
diagramming of the Swedish/German/Easter star.





Date: Tue, 29 Mar 94 15:38:51 AST
From: arien kismet del'tai <arien@blegga.omnigroup.com>
Subject: Stylized folds

        Preliminary rambling:  I think my tastes were
shaped by the origami book from which I learned, Sakoda's
_Modern Origami_ (which is now rather yellowed with age.
However, I prefer his stylized works (three limbs and all
:-) ) to most of Montroll's (although I must get his and
Lang's _Origami Sea Life_), since to me the latter often
seem crumpled rather than elegant in their efforts to be
exact.  I've in mind the Brachiosaurus on the cover of
_Prehistoric Origami_ as an example.
        Folds I particularly like in MO are the pegasus
(one of the ones I first learned to fold anywhere, anytime)
from his eight-pointed star, the flying crane and Egyptian
cat from the offset bird base, the fox and camel from the
T-fold, and the monk from thw owl base.  (Hm, I can see
upon looking over the book that I need to try some of
these, like the standing crane, some more with foil paper.)
        My question is, then, what books would you
specifically recommend that have a similar style?

        I know when I see the books themselves I can decide
from the pictures, but in many cases I might have to
mail-order.  I've primarily seen Fuse's (yay) and
Montroll's books in the stores in the University District
(but then, I haven't yet gone to one or two major Seattle
stores that're out of the area), plus _Origami for the
Connoisseur_ which overall I greatly enjoy.

               Thanks!
                     Arien.





Date: Tue, 29 Mar 94 16:11:50 AST
From: Soylent Green <rhudson@yorkcol.edu>
Subject: kawasaki's rose

Whichever rose is in "Origami for the Connoiseur" is a good model, the only
thing "imperfect" about it is the lock on the bottom.. if there were a better
lock, then I would probably classify that as "near" perfect.. now if only there
were a decent modular rose and leaf/stem apparatus...

Rob





Date: Tue, 29 Mar 94 16:29:34 AST
From: Joseph Wu <jwu@cs.ubc.ca>
Subject: Re: kawasaki's rose

On Tue, 29 Mar 1994, Soylent Green wrote:

> Whichever rose is in "Origami for the Connoiseur" is a good model, the only
> thing "imperfect" about it is the lock on the bottom.. if there were a better
> lock, then I would probably classify that as "near" perfect.. now if only
     there
> were a decent modular rose and leaf/stem apparatus...

Ah...but if you work at it, the lock *IS* a perfect lock.





Date: Tue, 29 Mar 94 20:36:14 AST
From: LONNIER@nickel.mincom.oz.au
Subject: Ghostscript

Does anyone know if Ghostscript will print to a Cannon Bubble Jet printer.
This is not one of the available printers Thus far I have
had no success....





Date: Tue, 29 Mar 94 22:27:48 AST
From: Soylent Green <rhudson@yorkcol.edu>
Subject: Re: kawasaki's rose

Whaddya mean?  Send me the perfect lock.. and by working on it, I DON'T mean
cutting, glueing, or even scotch-taping! :)

Rob, "the Pure One"





Date: Wed, 30 Mar 94 01:59:37 AST
From: Joseph Wu <jwu@cs.ubc.ca>
Subject: Re: kawasaki's rose

On Tue, 29 Mar 1994, Soylent Green wrote:

> Whaddya mean?  Send me the perfect lock.. and by working on it, I DON'T mean
> cutting, glueing, or even scotch-taping! :)

Neither do I. I mean working the paper together to form a proper 4-flap
lock. It works. I can do it in my sleep from an 18.75 mm square. If it
didn't work properly as a lock, the leaf base I designed for it would be
almost totally useless since it is designed to be forced into the centre
of the lock where the 4 flaps meet.





Date: Wed, 30 Mar 94 02:48:45 AST
From: Joseph Wu <jwu@cs.ubc.ca>
Subject: Re: Papers

On Fri, 25 Mar 1994 r.follmer@genie.geis.com wrote:

> My hunch is that there are basic types of papers and that some of these
> names are perhaps well known trade names in Japan.

You are correct. These are all types of papers. I don't think that there
are any trade names in the list you gave. I'll try to explain what I know.

Chiyogami is paper decorated in a traditional Japanese pattern. Most of it
exists as standard kami-weight paper (standard origami paper) with a
design printed on.

> edo chiyogami
>  saiun chiyogami -- has cloud-like patterns with traditional designs
                      embedded in it; 4 colour/pattern combinations
>  mingei chiyogami
>  shibori craft chiyogami -- 4 traditional single-colour designs printed
                              on brown kraft (recycled) paper
>  hanshi ban gokujo chiyogami
>  gokujo chirmen chiyogami

Washi paper is the soft, thick Japanese paper that you often find with
chiyogami designs printed on it. The printing is often with a raised ink
that gives it a very rich feel. Technically, washi refers to the traditional
handmade Japanese paper made from pulp derived from mulberry bark. Nowadays,
machinemade papers of the same materials and of similar texture are also
called by this name. The rest of this is speculation, but I think that the
words yuzen, aziome and wazome refer to particular styles of print patterns
with yuzen being very densely patterned, aziome being very dark, and shin
wazome being lighter and less densly patterned. Mingei appears to refer to
solid coloured washi.

>  washi chiyogami -- standard washi with traditional designs
>  wazome & unyru washi
>  itajime some washi
>  momi some washi -- a very soft washi that feels like cloth; I wouldn't
                      recommend it for folding
>  yuzen & mingei washi
>  aziome washi
>  yuzen kagayaki washi
>  nippon iro hakebiki washi
>  gokujo washi

>  koma
>  pitatto duo foil -- foil on one side, patterned paper on the other.
>  tsuya color
>  ryomen zome duo side monochrome
>  rameru waves
>  hakutsuru
>  kinsai
>  ginsai
>  kotobuki yuzen
>  miyabi yuzen
>  fashion  kusudama -- kusudama papers are double sided kami-weight papers
                        with solid colour on one side and either a solid colour
                        or a pattern on the other side; I suspect that fashion
                        kusudama means that the pattern is of clothing.

That's about all I can tell you right now. My books with more info on this
topic have been borrowed by various people. Who's catalog did you get anyway?
I recognize some of the papers as being distributed by Grimmhobby.





Date: Wed, 30 Mar 94 05:49:02 AST
From: Bruce Stephens <bruce@liverpool.ac.uk>
Subject: Re: kawasaki's rose

> Whichever rose is in "Origami for the Connoiseur" is a good model, the only
> thing "imperfect" about it is the lock on the bottom.. if there were a better
> lock, then I would probably classify that as "near" perfect.. now if only
     there
> were a decent modular rose and leaf/stem apparatus...

There are variations on Kawasaki's rose.  The essential rose bit seems to be
the twist fold together with one set of diagonal creases (diagonal wrt the
folds used in the twist).  By rotating the rose in Connoiseur by 45 degrees,
you can make a rose with a variable size, depending on how wide you make
the twist folds (which now run across and down the square), and the lock has
to be made on the end of a tube which is nice and flat.

There's a nice version of the lock for this kind of rose which fits into
a leaf by (I think) Ted Norrington---makes a lovely buttonhole.

You can also fold multiples of this kind of rose in a single sheet, making
a tray of them.  I drew diagrams for this which are in the archive.  (There's
an error in the diagrams; one of the dimensions is wrong, but you should
be able to spot it.)

Bruce                   Institute of Advanced Scientific Computation
bruce@liverpool.ac.uk   University of Liverpool





Date: Wed, 30 Mar 94 10:24:38 AST
From: Bruce Stephens <bruce@liverpool.ac.uk>
Subject: Re: kawasaki's rose

> Could you maybe do up a description or a draw'ring?
>
> Rob

Assuming you were referring to me, yes, I'll have a go sometime
in mid-April (I'm off on holiday in the meantime).

Bruce                   Institute of Advanced Scientific Computation
bruce@liverpool.ac.uk   University of Liverpool





Date: Wed, 30 Mar 1994 09:52:27 -0400 (AST)
From: Soylent Green <rhudson@yorkcol.EDU>
Subject: Re: kawasaki's rose

Could you maybe do up a description or a draw'ring?

Rob





Date: Wed, 30 Mar 94 11:44:10 AST
From: Soylent Green <rhudson@yorkcol.edu>
Subject: Bruce yes (rose)

Sounds good, Bruce.. I've basically locked the sucker with a "overlap" similar
to the old cardboard box flap jobbie, but it seems to always slip apart.  I'd
also like the leaf and stem apparatus info if you have it (might even be
willing to GASP! glue it if it works right.. could make an attractive display..

Rob
