From: John De Armond
Subject: Re: Opinions on software
Date: 2000/03/31
Message-ID: <38E4767A.56EE19E4@bellsouth.net>
Newsgroups: rec.crafts.glass

Queen Bee wrote:

> I had another recommendation today for the Photoshop/Illustrator
> combo.  Adobe has free downloads available, so I'm going to play with
> those for a bit.  Thanks!

Before you waste a lot of effort and money, consider a few things.
I have not seen these application-specific CAD programs for stained
glass but I do use a neon CAD program called Neon Wizard for making
neon patterns.  The applications are similar.  I also use CorelDraw
and Adobe Illustrator plus CAD software.

What the application-specific CAD (ASC) package brings to you is the
embedded design rules necessary to make the product.  For making
neon, for example, the Neon Wizard "knows" what the minimum bend
radius of a given size tubing is and will not let me draw (or at
least makes me work at it) a pattern that violates this "design
rule".  Another feature is that it has typefaces that look "good"
when made into neon.  The stained glass ASC should know the rules
about lead lines, foil allowances, minimum cutting widths and the
like.  It also should make it easy to lay down repeating patterns
such as checkerboard patterns that would have to be drawn by hand in
general drawing packages.

OTOH, these ASC packages are generally not the best at "drawing".
You can't expect a one man or small shop product to have the
refinement of drawing of, say, CorelDraw or Illustrator.  I
generally do my preliminary sketching and rough drawings in Corel or
Illustrator, export a vector file to Neon Wizard and "neonize" it.
For simple work, I then export THAT vector file back to Corel for
printing or plotting because Corel's output control is much better.
For more complex work, I export to a CAD package for output because
the output control in CAD software is even better. This sounds kinda
kludgy but it's actually easier than it sounds.  While ASC packages
such as Neon Wizard promote themselves as complete packages, in
reality they cannot be.  I viewed my purchase of Neon Wizard as
buying a set of design rules implemented in software.

Neon Wizard costs $1000 so obviously I didn't start out in the
business buying such a package.  I made a LOT of neon using
CorelDraw.  Even after developing (and copying from others) many
tricks, making a ready-to-bend pattern for neon is tedium defined.
My wife is a stained glass artist and she would agree with this for
making glass patterns too.  It's kinda like driving a nail with a
crescent wrench - it can be done but it's certainly not the best
way.

Actually, drawing packages such as Corel and Illustrator are greatly
inferior to true CAD packages for creating patterns that have to be
dimensionally correct.  The concept of dimensional accuracy has just
recently been incorporated into both Corel and Illustrator and even
now, the process breaks down, depending on the output device and its
accompanying windoze driver.  OTOH, the basic ground rule for all
CAD packages is that they have to generate drawings that are
dimensionally accurate to a degree suitable for actual manufacturing
using takeoff measurements from the blueprint.  Using a pro CAD
package and an Hewlett-packard engineering plotter, for example,
lines can be laid down with an absolute accuracy of +-0.001".

CAD packages also have a much richer set of drawing tools (not to be
confused with effects tools such as drop shadows, fountain fills and
all the other bells and whistles in draw packages.)  Corel and
Illustrator can, for example draw ellipses, circles (special case of
the ellipse) and Biezer curves.  AutoCAD (and most others too) can
draw true circles, ellipses to specified dimensions, cubic spline
curves (much more accurate for controlled dimensioned objects), true
tangent circles and curves and a wide variety of others.  While one
can eventually achieve a similar effect (though probably at lower
accuracy) with the draw packages, one will waste a lot of time
futzing with object controls to do what a CAD package does with one
command.

Another major issue is outputting your artwork.  If your artwork is
larger than the paper size of your printer/plotter, it must be
tiled.  While both Corel and Illustrator have some sort of tiling,
it is not very accurate.  Corel handles 4-way tiling OK (output to 4
sheets of paper that are trimmed and then taped together).  It
usually blows up at 6-way tiling and almost always blows up on 8-way
(comments apply to Corel Vers 8 and below).  I suspect that much of
the problem is the windoze driver.  CAD packages usually have the
ability to bypass windoze's drivers and directly drive the output.
The selection of output devices is more limited but the major ones
are supported.

If you do pieces of any size at all, tiling gets very tedious, even
when the output goes well.  Taping all those pieces of paper
together is very tedious.  What you really need is a large output
device that can output onto architectural "D" or "E" sized paper.
The traditional device is the engineering pen plotter, where the
pattern is actually drawn on the paper by a computerized pen.
Nowadays, the standard device is the large format engineering inkjet
printer.  Hewlett-Packard is the dominant player in this market.
Large format inkjet printers start at $1995 and up.  Way up!
Fortunately for us, the older pen plotters are still perfectly
useable and are dirt-cheap.  I bought my HP DraftPro, an  8 color, 8
pen "D" size plotter (24" wide paper by up to about 60" long) for
$80!  They are widely available because of the widespread adaptation
of wide format printers and because of the huge cutbacks in the
defense industry.

Windoze has a basic HPGL (hewlett-packard graphics language - the
standard plotter language) driver but it's not very good.  Draw
packages have to use this driver.  CAD packages almost always have a
dedicated HPGL driver.  It gives much finer control over the
plotter's operation.  Tiling is generally very well handled for
plotter output.  It's hard to imagine a glass panel that would
require much more than 4-way tiling on a "D" (24 X 36") or "E" (36 X
48") plotter.  One nifty thing about HPGL is that it consists of
simple, human understandable commands such as pen up, pen down,
movement and so on, in an ASCII file that can be edited with any
text editor.  Movement commands are in units of thousands of an
inch.  It is sometimes faster to make minor corrections to an HPGL
file than it is to edit the drawing and then re-output.

The major problem with CAD packages has traditionally been the
cost.  I paid $2000 for my first copy of AutoCad over 15 years ago!
That problem is now gone.  Nowadays, low cost ( <$100) and
absolutely free, fully functional packages are available.  AutoCad
is the industry standard so most packages emulate AutoCad.  An
excellent, FREE package that emulates AutoCad is Intellicad,
available from http://www.cadopia.com/.  Intellicad is an
interesting product.  Developed and then abandoned by Visio Corp,
the source code for this package was given to an open source
consortium that was formed to continue supporting it.  Member
companies like cadopia give it away and sell upgrades and extensions
or they enhance it and shrink-wrap market it.  Anyway, Intellicad is
a very good CAD package that is free for the price of downloading an
about 13mb file.

One neat thing Intellicad is that CAD applications, such as a
stained glass drawing package, can be written in VBA (visual basic
for applications) and incorporated into Intellicad as an extension.
A motivated glass artist could fairly quickly whip out a
stained-glass-specific CAD package that would rival the commercial
ones.

Enough of that.  I recommend that before you spend a lot of money on
general draw package and then spend a LOT of time trying to create
stained glass patterns with same, you take a look both at Intellicad
and the application-specific CAD packages previously mentioned.
CorelDraw is a good product to have around for general drawing and
creative work but I'd hate to have to do much pattern work in it.
Adobe Illustrator is a professional illustrator package.  As such,
it is both expensive and has a steep learning curve and still is not
a good pattern program.  I use it professionally but I would not
recommend it to a casual user.

John

From: John De Armond
Subject: Re: Opinions on software
Date: 2000/04/04
Message-ID: <38E9AE89.DC1F13CB@bellsouth.net>
Newsgroups: rec.crafts.glass

db wrote:
>
> Neon John <johngdNOSPAM@bellsouth.net> wrote in message
> news:38E4767A.56EE19E4@bellsouth.net...
> >
> >  The stained glass ASC should know the rules
> > about lead lines, foil allowances, minimum cutting widths and the
> > like.  It also should make it easy to lay down repeating patterns
> > such as checkerboard patterns that would have to be drawn by hand in
> > general drawing packages.
> >
>
> Yes, they should. I wonder if they do. Pattern fills in general are easy to
> use in Corel and Illustrator, but they would not be stained-glass specific
> unless you went to some trouble to create your own fill and save it.

I guess the term "easy" is relative but I find Corel's pattern fill
to be right in there with root canals.  Especially when adjacent
filled blocks have to register.

>
> >The concept of dimensional accuracy has just
> > recently been incorporated into both Corel and Illustrator and even
> > now, the process breaks down, depending on the output device and its
> > accompanying windoze driver.
>
> The drawing packages are expected to product print-ready output, accurate
> enough to register color plate reproduction. I've never worried too much
> about dimensional accuracy.

Published a (real paper) magazine for a couple of years using Corel
and PageMaker so I'm still kinda bloody from the experience.  In the
process, I learned all about this.  Trying to print the pattern to a
printed circuit board and hold the tolerance to +-0.050 was a real
trial-and-error trick.

You must understand the distinction between accuracy and precision.
A 2250dpi imagesetter has tremendous precision, better than 1 part
in 2250, but its accuracy, e.g., how faithfully it reproduces a
given dimension is poor.  Registration between color plates only
requires the imagesetter to be reproducible, and not to that great a
degree.  If the registration is +- the width of a hairline at the
machine resolution, that's more than enough.  A machine that can do
that may, at the same time, have a placement accuracy (distance from
the side and top of the sheet edges) as poor as 0.1".  Doesn't
matter on the press since the plate is moved around to center it on
the press anyway, but it does matter when the pattern you're
outputting has to fit dimensions created by others (such as the
dimensions of a door opening.)

I should also note that these imagers invariably use PostScript
which is a great deal less variable than raster devices - what most
of our printers are.

>You have me wondering now. If its over .01 inch
> innacurate, I'd like to at least know about it.  I think next time I go to
> the blueprint guy, I'm going to take a test drawing digital master with
> precise calibration of squares and circles and stuff and have him print it
> out exactly as the file states. Then take it home and measure it.

Here's a way to see Corel at work.  Make a 1" square.  Step and
repeat it across the page so that the edges of adjacent squares
precisely overlap.  If you zoom in as tightly as Corel will go, you
will (sometimes but not always) see that the step-and-repeat was not
precise, even if you use the snap function.  This problem has been
in Corel from the beginning to at least V8 and is an artifact of
rounding errors inside the program.  Then if you do this enough that
it will cover 4 or more pages, the pages will NOT register most of
the time.  The nasty thing about rounding errors is that they sneak
up on you.  A dimension can be accurate in one instance and after
you make a minor change, suddenly it's way off.

This may or may not bother you.  It bothers me in my neon work a lot
since I frequently have to make my glass fit a sign frame fabricated
by another shop.  I suspect it will bother the stained glass artist
when one has to fit the piece to an existing object such as a door.
I know that the times my wife has tried to use the computer to make
a pattern to fit a door opening, we had a hell of a time getting a
pattern that was accurate enough without several tries.  and that
was using a plotter, which is much more accurate than my Canon
printer.


> >Movement commands are in units of thousands of an
> > inch.  It is sometimes faster to make minor corrections to an HPGL
> > file than it is to edit the drawing and then re-output.
>
> geek
>
> > One neat thing Intellicad is that CAD applications, such as a
> > stained glass drawing package, can be written in VBA (visual basic
> > for applications) and incorporated into Intellicad as an extension.
> > A motivated glass artist could fairly quickly whip out a
> > stained-glass-specific CAD package that would rival the commercial
> > ones.
> >
>
> major geek

Well yeah :-)  But which route do you suspect would produce a better
application - one written by a programmer trying to understand
stained glass or a glass artist who taught him/herself enough
programming to make it happen?  I operate in both areas and I'll bet
on the artist, if the application is built to run inside one of
these CAD packages.  Now the REAL geeks are those who wrote
applications in AutoCad's Forth language.

>
> > Enough of that.  I recommend that before you spend a lot of money on
> > general draw package and then spend a LOT of time trying to create
> > stained glass patterns with same, you take a look both at Intellicad
> > and the application-specific CAD packages previously mentioned.
> > CorelDraw is a good product to have around for general drawing and
> > creative work but I'd hate to have to do much pattern work in it.
> > Adobe Illustrator is a professional illustrator package.  As such,
> > it is both expensive and has a steep learning curve and still is not
> > a good pattern program.  I use it professionally but I would not
> > recommend it to a casual user.
>
> I agree that Illustrator isn't a pattern making tool by design, but I still
> recommend everyone try PhotoShop and Illustrator, or  the Corel Suite.
> There's others too. Just because they're fun to fool around with.  Get a
> digital sketch pad and draw stuff. Whip up a design in Photoshop with paint
> brushes and layers and scans of pieces of glass, squish it around, add a
> filter to it, warp it . Send it out to Illustrator, trace it, outline it in
> black, just fool around.

I agree with that part about fun to play with but!  You're talking
about a sack-full of money to go out and buy Corel and Illustrator.
The demos are pretty worthless.  I guess used copies are an option.
Yeah, I know a lot of people bootleg these programs but I'm not
going to recommend that plus you really need the factory manual to
learn these programs, IMHO.

John